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author | Thomas Schwinge <tschwinge@gnu.org> | 2008-11-14 00:07:38 +0100 |
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committer | Thomas Schwinge <tschwinge@gnu.org> | 2008-11-14 00:07:38 +0100 |
commit | 84bac506a38900563a938ecc97ec638dda736f02 (patch) | |
tree | e3356804331355cc19920d23598bdb21e7bf9198 /hurd | |
parent | 02bcc0768865302843ef96183f825a2453dd5d12 (diff) | |
parent | 8f929bde2919c770b1f26397567526626e0683f2 (diff) |
Merge branch 'homepage'
Diffstat (limited to 'hurd')
54 files changed, 4097 insertions, 57 deletions
diff --git a/hurd/advantages.mdwn b/hurd/advantages.mdwn new file mode 100644 index 00000000..ff8c5560 --- /dev/null +++ b/hurd/advantages.mdwn @@ -0,0 +1,60 @@ +[[meta copyright="Copyright © 2001, 2002, 2008 Free Software Foundation, +Inc."]] + +[[meta license="""[[toggle id="license" text="GFDL 1.2+"]][[toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled +[[GNU_Free_Documentation_License|/fdl]]."]]"""]] + +The Hurd is not the most advanced kernel known to the planet (yet), +but it does have a number of enticing features: + + * **it's free software** + + Anybody can use, modify, and redistribute it under the terms of the + [[GNU_General_Public_License_(GPL)|GPL]] + + * **it's compatible** + + The Hurd provides a familiar programming and user environment. For all + intents and purposes, the Hurd is a modern Unix-like kernel. The Hurd uses + the [[GNU_C_Library|glibc]], whose development closely tracks standards + such as ANSI/ISO, BSD, POSIX, Single Unix, SVID, and X/Open. + + * **it's built to survive** + + Unlike other popular kernel software, the Hurd has an object-oriented + structure that allows it to evolve without compromising its design. This + structure will help the Hurd undergo major redesign and modifications + without having to be entirely rewritten. + + * **it's scalable** + + The Hurd implementation is aggressively multithreaded so that it runs + efficiently on both single processors and symmetric multiprocessors. The + Hurd interfaces are designed to allow transparent network clusters + (*collectives*), although this feature has not yet been implemented. + + * **it's extensible** + + The Hurd is an attractive platform for learning how to become a kernel + hacker or for implementing new ideas in kernel technology. Every part of + the system is designed to be modified and extended. + + * **it's stable** + + It is possible to develop and test new Hurd kernel components without + rebooting the machine (not even accidentally). Running your own kernel + components doesn't interfere with other users, and so no special system + privileges are required. The mechanism for kernel extensions is secure by + design: it is impossible to impose your changes upon other users unless + they authorize them or you are the system administrator. + + * **it exists** + + The Hurd is real software that works Right Now. It is not a research + project or a proposal. You don't have to wait at all before you can start + using and developing it. diff --git a/hurd/authentication.mdwn b/hurd/authentication.mdwn index cbb164c8..14144d8e 100644 --- a/hurd/authentication.mdwn +++ b/hurd/authentication.mdwn @@ -10,7 +10,7 @@ is included in the section entitled UIDs on the Hurd are separate from processes. A process has [[capabilities|capability]] designating so-called UID vectors that -are implemented by an [[auth]] server. This +are implemented by an [[translator/auth]] server. This makes them easily [[virtualizable|virtualization]]. When a process wishes to gain access to a resource provided by a third diff --git a/hurd/building.mdwn b/hurd/building.mdwn index 7a24f70a..01586c84 100644 --- a/hurd/building.mdwn +++ b/hurd/building.mdwn @@ -16,7 +16,7 @@ within a Debian system. ## Getting the Source Code You can chose between getting the [sources from the developers's -RCS](http://www.gnu.org/software/hurd/download.html#cvs): +RCS](http://savannah.gnu.org/cvs/?group=hurd): $ cvs -z3 -d:pserver:anonymous@cvs.savannah.gnu.org:/sources/hurd co hurd diff --git a/hurd/building/cross-compiling.mdwn b/hurd/building/cross-compiling.mdwn index 11afc97f..e548c75c 100644 --- a/hurd/building/cross-compiling.mdwn +++ b/hurd/building/cross-compiling.mdwn @@ -98,7 +98,7 @@ guarantee is given. Always the preferred version is listed first. `gcc-4_3-branch` needs. --> -* `src/gnumach`: [[GNU_Mach|microkernel/mach/gnumach]] +* `src/gnumach`: [[microkernel/mach/GNU_Mach]] * CVS `gnumach-1-branch` @@ -110,7 +110,7 @@ guarantee is given. Always the preferred version is listed first. $ ( cd gnumach-1-branch/ && autoreconf -vfi ) -* `src/mig`: [[GNU_Mach_Interface_Generator|microkernel/mach/mig]] +* `src/mig`: [[microkernel/mach/mig/GNU_MIG]] * CVS `HEAD` diff --git a/hurd/critique.mdwn b/hurd/critique.mdwn index 9770138e..dacd7bb8 100644 --- a/hurd/critique.mdwn +++ b/hurd/critique.mdwn @@ -8,8 +8,8 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] -[[NealWalfield]] and [[MarcusBrinkmann]] wrote a paper titled [*A Critique of -the GNU Hurd Multi-Server Operating +Neal Walfield and Marcus Brinkmann wrote a paper titled [*A Critique of +the GNU Hurd Multi-server Operating System*](http://walfield.org/papers/200707-walfield-critique-of-the-GNU-Hurd.pdf). This was published in ACM SIGOPS Operating Systems Review in July 2007. This is sometimes referred to as *the critique*. diff --git a/hurd/debugging/subhurd.mdwn b/hurd/debugging/subhurd.mdwn index caad950b..7b5b07b1 100644 --- a/hurd/debugging/subhurd.mdwn +++ b/hurd/debugging/subhurd.mdwn @@ -85,6 +85,6 @@ W3 Sources: -* <http://www.gnu.org/software/hurd/howto/subhurd.html> +* [[subhurd/running_a_subhurd]] * <http://lists.gnu.org/archive/html/bug-hurd/2007-02/msg00030.html> * [[Thomas_Schwinge|tschwinge]]'s mind diff --git a/hurd/documentation.mdwn b/hurd/documentation.mdwn index 4d431b0b..be0874e7 100644 --- a/hurd/documentation.mdwn +++ b/hurd/documentation.mdwn @@ -1,4 +1,5 @@ -[[meta copyright="Copyright © 2008 Free Software Foundation, Inc."]] +[[meta copyright="Copyright © 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 +Free Software Foundation, Inc."]] [[meta license="""[[toggle id="license" text="GFDL 1.2+"]][[toggleable id="license" text="Permission is granted to copy, distribute and/or modify this @@ -8,6 +9,57 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] +# Introductory Material + + * [[What_Is_the_GNU_Hurd]] + + * [[Advantages]] + * [[FAQ]] - * <http://www.gnu.org/software/hurd/docs.html> + * [[*The_Hurd_and_Linux*|hurd-and-linux]], a comment by Richard Stallman. + + * [[*Towards_a_New_Strategy_of_OS_Design*|hurd-paper]], an architectural + overview by Thomas Bushnell, BSG. + + * [[*The_Hurd*|hurd-talk]], a presentation by Marcus Brinkmann. + + * A document about *[[translators]]* by Marcus Brinkmann. + + * [[*A_Critique_of_the_GNU_Hurd_Multi-server_Operating_System*|critique]], an + analysis of the GNU Hurd on GNU Mach system, written by Neal Walfield and + Marcus Brinkmann. + +## External + + * [*Examining the Legendary HURD + Kernel*](http://www.informit.com/articles/printerfriendly.aspx?p=1180992), + an article by David Chisnall. + + Also covers a bit of GNU's and the Hurd's history, fundamental techniques + applied, comparisions to other systems. + + +# Development + + * *[[The_GNU_Hurd_Reference_Manual|reference_manual]]*. + + * The *[[Hurd_Hacking_Guide]]*, an introduction to GNU Hurd and Mach + programming by Wolfgang Jährling. + + * [*Manually Bootstrapping a + Translator*](http://walfield.org/pub/people/neal/papers/hurd-misc/manual-bootstrap.txt), + a text by Neal Walfield about how to *manually connect the translator to + the filesystem*. + + * [[*The_Authentication_Server*|auth]], the transcript of a talk about the + details of the authentication mechanisms in the Hurd by Wolfgang Jährling. + + * [*The Mach Paging Interface as Used by the + Hurd*](http://lists.gnu.org/archive/html/l4-hurd/2002-06/msg00001.html), a + text by Neal Walfield. + + * In the + [[Position_paper_*Improving_Usability_via_Access_Decomposition_and_Policy*|ng/position_paper]] + Neal Walfield and Marcus Brinkmann give an overview about how a future, + subsequent system may be architected. diff --git a/hurd/documentation/auth.html b/hurd/documentation/auth.html new file mode 100644 index 00000000..487fc1fe --- /dev/null +++ b/hurd/documentation/auth.html @@ -0,0 +1,168 @@ +[[meta copyright="Copyright © 2002, 2008 Free Software Foundation, Inc."]] + +[[meta license="Verbatim copying and distribution of this entire article is +permitted in any medium, provided this notice is preserved."]] + +[[meta title="The Authentication Server, the transcript of a talk about the +details of the authentication mechanisms in the Hurd by Wolfgang Jährling"]] + +<H3><A NAME="contents">Table of Contents</A></H3> +<UL> + <LI><A HREF="#intro" NAME="TOCintro">Introduction</A> + <LI><A HREF="#ids" NAME="TOCids">How IDs are represented and used</A> + <LI><A HREF="#posix" NAME="TOCposix">POSIX and beyond</A> + <LI><A HREF="#servers" NAME="TOCservers">Related servers</A> +</UL> +<HR> + +<H3><A HREF="#TOCintro" NAME="intro">Introduction</A></H3> +<P> +In this text, which mostly resembles the talk I gave at Libre Software +Meeting 2002 in Bordeaux, I will describe what the auth server does, +why it is so important and which cool things you can do with it, both +on the programming and the user side. I will also describe related +programs like the password and fakeauth servers. Note that this text +is targeted at programmers who want to understand the auth mechanism +in detail and are already familiar with concepts like Remote Procedure +Calls (RPCs) as well as the way User- and Group-IDs are used in the +POSIX world. + +<P> +The auth server is a very small server, therefore it gives a useful +example when you want to learn how a server typically looks like. One +reason why it is so small is that the auth interface, which it +implements, consists of only four RPCs. You can find the interface in +hurd/hurd/auth.defs and the server itself in hurd/auth/. + +<H3><A HREF="#TOCids" NAME="ids">How IDs are represented and used</A></H3> +<P> +Each process holds (usually) one port to auth (an auth_t in C source, +which actually is a mach_port_t, of course). The purpose of auth is +to manage User-IDs and Group-IDs, which is the reason why users often +will have no choice but to make use of the systems main auth server, +which does not listen on /servers/auth; instead you inherit a port to +auth from your parent process. Each such port is (internally in the +auth server) associated with a set of effective User- and Group-IDs as +well as a set of available User- and Group-IDs. So we have four sets +of IDs in total. The available IDs can be turned into corresponding +effective IDs at any time. + +<P> +When you send an auth_getids RPC on the port you hold, you will get +information about which IDs are associated with it, so you can figure +out which permissions you have. But how will a server know that you +have these permissions and therefore know which actions (e.g. writing +into file "foo") it is supposed to do on your behalf and which not? +The establishing of a trusted connection to a server works as follows: + +<P><OL> +<LI>A user wants a server to know its IDs</LI> +<LI>The user requests a reauthentication from the server</LI> +<LI>In this request the user will include a port</LI> +<LI>Both will hand this port to auth</LI> +<LI>The user uses auth_user_authenticate</LI> +<LI>The server uses auth_server_authenticate</LI> +<LI>The server also passes a new port to auth</LI> +<LI>auth matches these two requests</LI> +<LI>The user gets the new port from auth</LI> +<LI>The server learns about the IDs of the user</LI> +<LI>The user uses the new port for further communication</LI> +</OL> + +<P> +We have different RPCs for users and servers because what we pass and +what we get back differs for them: Users get a port, and servers get +the sets of IDs, and have to specify the port which the user will get. + +<P> +It is interesting to note that auth can match the requests by +comparing two integers, because when you get the same port from two +people, you will have the same mach_port_t (which is nothing but an +integer). + +<P> +All of this of course only works if they use the same auth server, +which is why I said often you have no choice other than to use the +one main auth server. But this is no serious restriction, as the auth server has +almost no functionality one might want to replace. In fact, there is +one replacement for the default auth implementation, but more on that +later. + +<H3><A HREF="#TOCposix" NAME="posix">POSIX and beyond</A></H3> +<P> +Before we examine what is possible with this design, let us take a +short look at how the POSIX semantics are implemented on top of this +design. When a program that comes out of POSIX-land asks for its own +effective User- or Group-ID, we will tell it about the first of the +effective IDs. In the same sense, the POSIX real User- or Group-ID is +the first available ID and the POSIX saved User- or Group-ID is the +second available ID, which is why you have the same ID two times in +the available IDs when you log into your GNU/Hurd machine (you can +figure out which IDs you have with the program "ids", that basically +just does an auth_getauth RPC). When you lack one of those IDs (for +example when you have no effective Group-ID), a POSIX program asking +for this particular information will get "-1" as the ID. + +<P> +But as you can imagine, we can do more than what POSIX specifies. Fox +example, we can modify our permissions. This is always done with the +auth_makeauth RPC. In this RPC, you specify the IDs that should be +associated with the new port. All of these IDs must be associated +with either the port where the RPC is sent to or one of the additional +ports you can specify; an exception is the superuser root, which is +allowed to creat ports that are associated with arbitrary IDs. +Hereby you can convert available into effective IDs. + +<P> +This opens the door to a bunch of nice features. For example, we have +the addauth program in the Hurd, which makes it possible to add an ID +to either a single process or a group of processes if you hold the ID or know the +appropriate password, and there is a corresponding rmauth program that +removes an ID. So when you are working on your computer with GNU +Emacs and want to edit a system configuration file, you switch to +Emacs' shell-mode, do an "addauth root", enter the password, edit the +file, and when you are done switch back to shell-mode and do "rmauth +root". These programs have some interesting options, and there are +various other programs, for setting the complete list of IDs (setauth) +and so on. + +<H3><A HREF="#TOCservers" NAME="servers">Related servers</A></H3> +<P> +Finally, I want to explain two servers which are related to auth. The +first is the password server, which listens on /servers/password. If +you pass to it a User- or Group-ID and the correct password for it, it +will return a port to auth to you which is associated with the ID you +passed to it. It can create such a port because it is running as +root. So let us assume you are an FTP server process. You will start +as root, because you want to use port 21 (in this case, "port" does +not refer to a mach_port_t, of course). But then, you can drop all +your permissions so that you run without any ID. This makes it far +less dangerous to communicate with yet unknown users over the +network. But when someone now hands a username and password to you, +you can ask the password server for a new auth port. The password +server will check the data you pass to it, for example by looking into +/etc/shadow, and if it is valid, it will ask the auth server for a new +port. It receives this port from auth and then passes it on to you. +So you have raised your permissions. (And for the very curious: Yes, +we are well aware of the differences between this concept and +capabilities; and we also do have some kinds of capabilities in +various parts of the Hurd.) + +<P> +My second example is the fakeauth server. It also implements the auth +protocol. It is the part of the fakeroot implementation that gives a +process the impression that it runs as root, even if it doesn't. So +when the process asks fakeauth about its own IDs, fakeauth will tell +the process that it runs as root. But when the process wants to make +use of the authentication protocol described earlier in this text, +fakeauth will forward the request to its own auth server, which will +usually be the systems main auth server, which will then be able to +match the auth_*_authenticate requests. So what fakeauth does is +acting as a proxy auth server that gives someone the impression to run +as root, while not modifying what that one is allowed to do. + +<P> +At this point, I have said at least most of what can be said about the +auth server and the protocol it implements, so I will finish by saying +that it might be an interesting task (for you) to modify some existing +software to take advantage of the features I described here. diff --git a/hurd/documentation/hurd-and-linux.html b/hurd/documentation/hurd-and-linux.html new file mode 100644 index 00000000..8eccd62c --- /dev/null +++ b/hurd/documentation/hurd-and-linux.html @@ -0,0 +1,47 @@ +[[meta copyright="Copyright © 1996, 1997, 1998, 2008 Free Software Foundation, +Inc."]] + +[[meta license="Verbatim copying and distribution of this entire article is +permitted in any medium, provided this notice is preserved."]] + +[[meta title="The Hurd and Linux"]] + +by <A HREF="http://www.stallman.org/">Richard Stallman</A>. + +<P> +People sometimes ask, ``Why did the FSF develop a new free kernel +instead of using Linux?'' It's a reasonable question. The answer, +briefly, is that that is not the question we faced. + +<P> +When we started developing the Hurd in 1990, the question facing us +was, ``How can we get a free kernel for the GNU system?'' There was +no free Unix-like kernel then, and we knew of no other plan to write +one. The only way we could expect to have a free kernel was to write +it ourselves. So we started. + +<P> +We heard about Linux after its release. At that time, the question +facing us was, ``Should we cancel the Hurd project and use Linux +instead?'' + +<P> +We heard that Linux was not at all portable (this may not be true +today, but that's what we heard then). And we heard that Linux was +architecturally on a par with the Unix kernel; our work was leading to +something much more powerful. + +<P> +Given the years of work we had already put into the Hurd, we decided +to finish it rather than throw them away. + +<P> +If we did face the question that people ask---if Linux were already +available, and we were considering whether to start writing another +kernel---we would not do it. Instead we would choose another project, +something to do a job that no existing free software can do. + +<P> +But we did start the Hurd, back then, and now we have made it work. +We hope its superior architecture will make free operating systems +more powerful. diff --git a/hurd/documentation/hurd-paper.html b/hurd/documentation/hurd-paper.html new file mode 100644 index 00000000..15d2daec --- /dev/null +++ b/hurd/documentation/hurd-paper.html @@ -0,0 +1,760 @@ +[[meta copyright="Copyright © 1996, 1997, 1998, 2007, 2008 Free Software +Foundation, Inc."]] + +[[meta license="Verbatim copying and distribution of this entire article is +permitted in any medium, provided this notice is preserved."]] + +[[meta title="Towards a New Strategy of OS Design, an architectural overview by +Thomas Bushnell, BSG."]] + + +This article explains why FSF is developing a new operating system named the +Hurd, which will be a foundation of the whole GNU system. +The Hurd is built +on top of CMU's Mach 3.0 kernel and uses Mach's virtual memory management and +message-passing facilities. +The GNU C Library will provide the Unix system +call interface, and will call the Hurd for needed services it can't provide +itself. +The design and implementation of the Hurd is being lead by Michael +Bushnell, with assistance from Richard Stallman, Roland McGrath, +Jan Brittenson, and others. + +<H2>Part 1: A More Usable Approach to OS Design</H2> +<P> +The fundamental purpose of an operating system (OS) is to enable a variety of +programs to share a single computer efficiently and productively. +This +demands memory protection, preemptively scheduled timesharing, coordinated +access to I/O peripherals, and other services. +In addition, an OS can allow +several users to share a computer. +In this case, efficiency demands services +that protect users from harming each other, enable them to share without +prior arrangement, and mediate access to physical devices. +<P> +On today's computer systems, programmers usually implement these goals +through a large program called the kernel. +Since this program must be +accessible to all user programs, it is the natural place to add functionality +to the system. +Since the only model for process interaction is that of +specific, individual services provided by the kernel, no one creates other +places to add functionality. +As time goes by, more and more is added to the +kernel. +<P> +A traditional system allows users to add components to a kernel only if they +both understand most of it and have a privileged status within the system. +Testing new components requires a much more painful edit-compile-debug cycle +than testing other programs. +It cannot be done while others are using the +system. +Bugs usually cause fatal system crashes, further disrupting others' +use of the system. +The entire kernel is usually non-pageable. +(There are +systems with pageable kernels, but deciding what can be paged is difficult +and error prone. +Usually the mechanisms are complex, making them difficult +to use even when adding simple extensions.) +<P> +Because of these restrictions, functionality which properly belongs +<STRONG>behind</STRONG> +the wall of a traditional kernel is usually left out of systems unless it is +absolutely mandatory. +Many good ideas, best done with an open/read/write +interface cannot be implemented because of the problems inherent in the +monolithic nature of a traditional system. +Further, even among those with +the endurance to implement new ideas, only those who are privileged users of +their computers can do so. +The software copyright system darkens the mire by +preventing unlicensed people from even reading the kernel source. +<P> +Some systems have tried to address these difficulties. +Smalltalk-80 and +the Lisp Machine both represented one method of getting around the problem. +System code is not distinguished from user code; all of the system is +accessible to the user and can be changed as need be. +Both systems were +built around languages that facilitated such easy replacement and extension, +and were moderately successful. +But they both were fairly poor at insulating +users and programs from each other, failing one of the principal goals of OS +design. +<P> +Most projects that use the Mach 3.0 kernel carry on the hard-to-change +tradition of OS design. +The internal structure is different, but the same +heavy barrier between user and system remains. +The single-servers, while +fairly easy to construct, inherit all the deficiencies of the monolithic +kernels. +<P> +A multi-server divides the kernel functionality up into logical blocks with +well-defined interfaces. +Properly done, it is easier to make changes and add +functionality. +So most multi-server projects do somewhat better. +Much more +of the system is pageable. +You can debug the system more easily. +You can +test new system components without interfering with other users. +But the +wall between user and system remains; no user can cross it without special +privilege. +<P> +The GNU Hurd, by contrast, is designed to make the area of +<STRONG>system</STRONG> +code as +limited as possible. +Programs are required to communicate only with a few +essential parts of the kernel; the rest of the system is replaceable +dynamically. +Users can use whatever parts of the remainder of the system +they want, and can easily add components themselves for other users to take +advantage of. +No mutual trust need exist in advance for users to use each +other's services, nor does the system become vulnerable by trusting the +services of arbitrary users. +<P> +This has been done by identifying those system components which users +<STRONG>must</STRONG> +use in order to communicate with each other. +One of these is responsible for +identifying users' identities and is called the +<DFN> +authentication server. +</DFN> +In +order to establish each other's identities, programs must communicate, each +with an authentication server they trust. +Another component establishes +control over system components by the superuser, provides global bookkeeping +operations, and is called the +<DFN> +process server. +</DFN> +<P> +Not all user programs need to communicate with the process server; it is only +necessary for programs which require its services. +Likewise, the +authentication server is only necessary for programs that wish to communicate +their identity to another. +None of the remaining services carry any special +status; not the network implementation, the filesystems, the program +execution mechanism (including setuid), or any others. + +<H3>The Translator Mechanism</H3> +<P> +The Hurd uses Mach ports primarily as methods for communicating between users +and servers. +(A Mach port is a communication point on a Mach task where +messages are sent and received.) Each port implements a particular set of +protocols, representing operations that can be undertaken on the underlying +object represented by the port. +Some of the protocols specified by the Hurd +are the I/O protocol, used for generic I/O operations; the file protocol, +used for filesystem operations; the socket protocol, used for network +operations; and the process protocol, used for manipulating processes et al. +<P> +Most servers are accessed by opening files. +Normally, when you open a file, +you create a port associated with that file that is owned by the server +that owns the directory containing the file. +For example, a disk-based +filesystem will normally serve a large number of ports, each of which +represents an open file or directory. +When a file is opened, the server +creates a new port, associates it with the file, and returns the port to the +calling program. +<P> +However, a file can have a +<DFN>translator</DFN> +associated with it. +In this case, +rather than return its own port which refers to the contents of the file, the +server executes a translator program associated with that file. +This +translator is given a port to the actual contents of the file, and is then +asked to return a port to the original user to complete the open operation. +<P> +This mechanism is used for +<CODE>mount</CODE> +by having a translator associated with +each mount point. +When a program opens the mount point, the translator (in +this case, a program which understands the disk format of the mounted +filesystem) is executed and returns a port to the program. +After the +translator is started, it need not be run again unless it dies; the parent +filesystem retains a port to the translator to use in further requests. +<P> +The owner of a file can associate a translator with it without special +permission. +This means that any program can be specified as a translator. +Obviously the system will not work properly if the translator does not +implement the file protocol correctly. +However, the Hurd is constructed so +that the worst possible consequence is an interruptible hang. +<P> +One way to use translators is to access hierarchically structured data using +the file protocol. +For example, all the complexity of the user interface to +the +<CODE>ftp</CODE> +program is removed. +Users need only know that a particular +directory represents FTP and can use all the standard file manipulation +commands (e.g +<CODE>ls</CODE> +or +<CODE>cp</CODE>) +to access the remote system, rather than learning +a new set. +Similarly, a simple translator could ease the complexity of +<CODE>tar</CODE> +or +<CODE>gzip</CODE>. +(Such transparent access would have some added cost, but it would +be convenient.) + +<H3>Generic Services</H3> +<P> +With translators, the filesystem can act as a rendezvous for interfaces which +are not similar to files. +Consider a service which implements some version +of the X protocol, using Mach messages as an underlying transport. +For each +X display, a file can be created with the appropriate program as its +translator. +X clients would open that file. +At that point, few file +operations would be useful (read and write, for example, would be useless), +but new operations ( +<CODE>XCreateWindow</CODE> +or +<CODE>XDrawText</CODE>) +might become meaningful. +In this case, the filesystem protocol is used only to manipulate +characteristics of the node used for the rendezvous. +The node need not +support I/O operations, though it should reply to any such messages with a +<CODE>message_not_understood</CODE> +return code. +<P> +This translator technique is used to contact most of the services in the Hurd +that are not structured like hierarchical filesystems. +For example, the +password server, which hands out authorization tags in exchange for +passwords, is contacted this way. +Network protocol servers are also +contacted in this fashion. +Roland McGrath thought up this use of translators. + +<H3>Clever Filesystem Pictures</H3> +<P> +In the Hurd, translators can also be used to present a filesystem-like view +of another part of the filesystem, with some semantics changed. +For example, +it would be nice to have a filesystem that cannot itself be changed, but +nonetheless records changed versions of its files elsewhere. +(This could be +useful for source code management.) +<P> +The Hurd will have a translator which creates a directory which is a +conceptual union of other directories, with collision resolution rules of +various sorts. +This can be used to present a single directory to users that +contains all the programs they would want to execute. +There are other useful +variations on this theme. + +<H3>What The User Can Do</H3> +<P> +No translator gains extra privilege by virtue of being hooked into the +filesystem. +Translators run with the uid of the owner of the file being +translated, and can only be set or changed by that owner. +The I/O and +filesystem protocols are carefully designed to allow their use by mutually +untrusting clients and servers. +Indeed, translators are just ordinary +programs. +The GNU C library has a variety of facilities to make common sorts +of translators easier to write. +<P> +Some translators may need special privileges, such as the password server or +translators which allow setuid execution. +These translators could be run by +anyone, but only if they are set on a root-owned node would they be able to +provide all their services successfully. +This is analogous to letting any +user call the +<CODE>reboot</CODE> +system call, but only honoring it if that user is root. + +<H3>Why This Is So Different</H3> +<P> +What this design provides is completely novel to the Unix world. +Until now, +OSs have kept huge portions of their functionality in the realm of system +code, thus preventing its modification and extension except in extreme need. +Users cannot replace parts of the system in their programs no matter how much +easier that would make their task, and system managers are loath to install +random tweaks off the net into their kernels. +<P> +In the Hurd, users can change almost all of the things that are decided for +them in advance by traditional systems. +In combination with the tremendous +control given by the Mach kernel over task address spaces and properties, the +Hurd provides a system in which users will, for the first time, be able to +replace parts of the system they dislike, without disrupting other users. +<P> +Most Mach-based OSs to date have mostly implemented a wider set of the +<STRONG> +same old +</STRONG> +Unix semantics in a new environment. +In contrast, GNU is extending +those semantics to allow users to improve, bypass, or replace them. + + +<H2>Part 2: A Look at Some of the Hurd's Beasts</H2> +<H3>The Authentication Server</H3> +<P> +One of the Hurd's more central servers is the authentication server. +Each +port to this server identifies a user and is associated by this server with +an +<DFN>id block</DFN>. +Each id block contains sets of user and group ids. +Either +set may be empty. +This server is not the same as the password server +referred to above. +<P> +The authentication server exports three services. +First, it provides simple +boolean operations on authentication ports: given two authentication ports, +this server will provide a third port representing the union of the two sets +of uids and gids. +Second, this server allows any user with a uid of zero to +create an arbitrary authentication port. +Finally, this server provides RPCs +(Remote Procedure Calls between different programs and possibly different +hosts) which allow mutually untrusting clients and servers to establish their +identities and pass initial information on each other. +This is crucial to +the security of the filesystem and I/O protocols. +<P> +Any user could write a program which implements the authentication protocol; +this does not violate the system's security. +When a service needs to +authenticate a user, it communicates with its trusted authentication server. +If that user is using a different authentication server, the transaction will +fail and the server can refuse to communicate further. +Because, in effect, +this forces all programs on the system to use the same authentication server, +we have designed its interface to make any safe operation possible, and to +include no extraneous operations. +(This is why there is a separate password +server.) +<H3>The Process Server</H3> +<P> +The process server acts as an information categorization repository. +There +are four main services supported by this server. +First, the process server +keeps track of generic host-level information not handled by the Mach kernel. +For example, the hostname, the hostid, and the system version are maintained +by the process server. +Second, this server maintains the Posix notions of +sessions and process groups, to help out programs that wish to use Posix +features. +<P> +Third, the process server maintains a one-to-one mapping between Mach tasks +and Hurd processes. +Every task is assigned a pid. +Processes can register a +message port with this server, which can then be given out to any program +which requests it. +This server makes no attempt to keep these message ports +private, so user programs are expected to implement whatever security they +need themselves. +(The GNU C Library provides convenient functions for all +this.) Processes can tell the process server their current `argv' and `envp' +values; this server will then provide, on request, these vectors of arguments +and environment. +This is useful for writing +<CODE>ps</CODE>-like +programs and also +makes it easier to hide or change this information. +None of these features +are mandatory. +Programs are free to disregard all of this and never register +themselves with the process server at all. +They will, however, still have a +pid assigned. +<P> +Finally, the process server implements +<DFN>process collections</DFN>, +which are used +to collect a number of process message ports at the same time. +Also, +facilities are provided for converting between pids, process server ports, +and Mach task ports, while ensuring the security of the ports managed. +<P> +It is important to stress that the process server is optional. +Because of +restrictions in Mach, programs must run as root in order to identify all the +tasks in the system. +But given that, multiple process servers could +co-exist, each with their own clients, giving their own model of the +universe. +Those process server features which do not require root privileges +to be implemented could be done as per-user servers. +The user's hands are +not tied. +<H3>Transparent FTP</H3> +<P> +Transparent FTP is an intriguing idea whose time has come. +The popular +<CODE>ange-ftp</CODE> +package available for GNU Emacs makes access to FTP files +virtually transparent to all the Emacs file manipulation functions. +Transparent FTP does the same thing, but in a system wide fashion. +This +server is not yet written; the details remain to be fleshed out, and will +doubtless change with experience. +<P> +In a BSD kernel, a transparent FTP filesystem would be no harder to write +than in the Hurd. +But mention the idea to a BSD kernel hacker, and the +response is that ``such a thing doesn't belong in the kernel''. +In a sense, +this is correct. +It violates all the layering principles of such systems to +place such things in the kernel. +The unfortunate side effect, however, is +that the design methodology (which is based on preventing users from changing +things they don't like) is being used to prevent system designers from making +things better. +(Recent BSD kernels make it possible to write a user program +that provides transparent FTP. +An example is +<CODE>alex</CODE>, +but it needs to run +with full root privileges.) +<P> +In the Hurd, there are no obstacles to doing transparent FTP. +A translator +will be provided for the node +<CODE>/ftp</CODE>. +The contents of +<CODE>/ftp</CODE> +will probably +not be directly listable, though further subdirectories will be. +There will +be a variety of possible formats. +For example, to access files on uunet, one +could +<CODE> +cd /ftp/ftp.uu.net:anonymous:mib@gnu. +</CODE> +Or to access files on a remote +account, one might +<CODE> +cd /ftp/gnu.org:mib:passwd. +</CODE> +Parts of this +command could be left out and the transparent FTP program would read them +from a user's +<CODE>.netrc</CODE> +file. +In the last case, one might just +<CODE> +cd /ftp/gnu.org; +</CODE> +when the rest of the data is already in +<CODE>.netrc</CODE>. +<P> +There is no need to do a +<CODE>cd</CODE> +first--use any file command. +To find out about +RFC 1097 (the Telnet Subliminal Message Option), just type +<CODE> +more /ftp/ftp.uu.net/inet/rfc/rfc1097. +</CODE> +A copy command to a local disk +could be used if the RFC would be read frequently. +<H3>Filesystems</H3> +<P> +Ordinary filesystems are also being implemented. +The initial release of the +Hurd will contain a filesystem upwardly compatible with the BSD 4.4 Fast File +System. +In addition to the ordinary semantics, it will provide means to +record translators, offer thirty-two bit user ids and group ids, and supply a +new id per file, called the +<DFN>author</DFN> +of the file, which can be set by the +owner arbitrarily. +In addition, because users in the Hurd can have multiple +uids (or even none), there is an additional set of permission bits providing +access control for +<DFN> +unknown user +</DFN> +(no uids) as distinct from +<DFN> +known but arbitrary user +</DFN> +(some uids: the existing +<DFN>world</DFN> +category of file +permissions). +<P> +The Network File System protocol will be implemented using 4.4 BSD as a +starting point. +A log-structured filesystem will also be implemented using +the same ideas as in Sprite, but probably not the same format. +A GNU network +file protocol may be designed in time, or NFS may be extended to remove its +deficiencies. +There will also be various ``little'' filesystems, such as the +MS-DOS filesystem, to help people move files between GNU and other OSs. + +<H3>Terminals</H3> +<P> +An I/O server will provide the terminal semantics of Posix. +The GNU C +Library has features for keeping track of the controlling terminal and for +arranging to have proper job control signals sent at the proper times, as +well as features for obeying keyboard and hangup signals. +<P> +Programs will be able to insert a terminal driver into communications +channels in a variety of ways. +Servers like +<CODE>rlogind</CODE> +will be able to insert +the terminal protocol onto their network communication port. +Pseudo-terminals will not be necessary, though they will be provided for +backward compatibility with older programs. +No programs in GNU will depend +on them. +<P> +Nothing about a terminal driver is forced upon users. +A terminal driver +allows a user to get at the underlying communications channel easily, to +bypass itself on an as-needed basis or altogether, or to substitute a +different terminal driver-like program. +In the last case, provided the +alternate program implements the necessary interfaces, it will be used by the +C Library exactly as if it were the ordinary terminal driver. +<P> +Because of this flexibility, the original terminal driver will not provide +complex line editing features, restricting itself to the behavior found in +Posix and BSD. +In time, there will be a +<CODE>readline</CODE>-based +terminal driver, +which will provide complex line-editing features for those users who want +them. +<P> +The terminal driver will probably not provide good support for the +high-volume, rapid data transmission required by UUCP or SLIP. +Those +programs do not need any of its features. +Instead they will be using the +underlying Mach device ports for terminals, which support moving large +amounts of data efficiently. + +<H3>Executing Programs</H3> +<P> +The implementation of the +<CODE>execve</CODE> +call is spread across three programs. +The +library marshals the argument and environment vectors. +It then sends a +message to the file server that holds the file to be executed. +The file +server checks execute permissions and makes whatever changes it desires in +the exec call. +For example, if the file is marked setuid and the fileserver +has the ability, it will change the user identification of the new image. +The file server also decides if programs which had access to the old task +should continue to have access to the new task. +If the file server is +augmenting permissions, or executing an unreadable image, then the exec needs +to take place in a new Mach task to maintain security. +<P> +After deciding the policy associated with the new image, the filesystem calls +the exec server to load the task. +This server, using the BFD (Binary File +Descriptor) library, loads the image. +BFD supports a large number of object +file formats; almost any supported format will be executable. +This server +also handles scripts starting with +<CODE>#!</CODE>, +running them through the indicated +program. +<P> +The standard exec server also looks at the environment of the new image; if +it contains a variable +<CODE>EXECSERVERS</CODE> +then it uses the programs specified +there as exec servers instead of the system default. +(This is, of course, +not done for execs that the file server has requested be kept secure.) +<P> +The new image starts running in the GNU C Library, which sends a message to +the exec server to get the arguments, environment, umask, current directory, +etc. +None of this additional state is special to the file or exec servers; +if programs wish, they can use it in a different manner than the Library. + +<H3>New Processes</H3> +<P> +The +<CODE>fork</CODE> +call is implemented almost entirely in the GNU C Library. +The new +task is created by Mach kernel calls. +The C Library arranges to have its +image inherited properly. +The new task is registered with the process server +(though this is not mandatory). +The C Library provides vectors of functions +to be called at fork time: one vector to be called before the fork, one after +in the parent, and one after in the child. +(These features should not be +used to replace the normal fork-calling sequence; it is intended for +libraries which need to close ports or clean up before a fork occurs.) +The C +library will implement both fork calls specified by the draft Posix.4a (the +proposed standard dealing with the threads extension to the real-time +extension). +<P> +Nothing forces the user to create new tasks this way. +If a program wants to +use almost the normal fork, but with some special characteristics, then it +can do so. +Hooks will be provided by the C Library, or the function can even +be completely replaced. +None of this is possible in a traditional Unix +system. + +<H3>Asynchronous Messages</H3> +<P> +As mentioned above, the process server maintains a +<DFN> +message port +</DFN> +for each +task registered with it. +These ports are public, and are used to send +asynchronous messages to the task. +Signals, for example, are sent to the +message port. +The signal message also provides a port as an indication that +the sender should be trusted to send the signal. +The GNU C Library lists a +variety of ports in a table, each of which identifies a set of signals that +can be sent by anyone who possesses that port. +For example, if the user +possesses the task's kernel port, it is allowed to send any signal. +If the +user possesses a special +<DFN> +terminal id +</DFN> +port, it is allowed to send the +keyboard and hangup signals. +Users can add arbitrary new entries into the C +library's signal permissions table. +<P> +When a process's process group changes, the process server will send it a +message indicating the new process group. +In this case, the process server +proves its authority by providing the task's kernel port. +<P> +The C library also has messages to add and delete uids currently used by the +process. +If new uids are sent to the program, the library adds them to its +current set, and then exchanges messages with all the I/O servers it knows +about, proving to them its new authorization. +Similarly, a message can +delete uids. +In the latter case, the caller must provide the process's task +port. +(You can't harm a process by giving it extra permission, but you can +harm it by taking permission away.) The Hurd will provide user programs to +send these messages to processes. +For example, the +<CODE>su</CODE> +command will be able +to cause all the programs in your current login session, to gain a new uid, +rather than spawn a subshell. +<P> +The C library will allow programs to add asynchronous messages they wish to +recognize, as well as prevent recognition of the standard set. +<H3>Making It Look Like Unix</H3> +<P> +The C Library will implement all of the calls from BSD and Posix as well as +some obvious extensions to them. +This enables users to replace those calls +they dislike or bypass them entirely, whereas in Unix the calls must be used +``as they come'' with no alternatives possible. +<P> +In some environments binary compatibility will also be supported. +This works +by building a special version of the library which is then loaded somewhere +in the address space of the process. +(For example, on a VAX, it would be +tucked in above the stack.) A feature of Mach, called system call +redirection, is then used to trap Unix system calls and turn them into jumps +into this special version of the library. +(On almost all machines, the cost +of such a redirection is very small; this is a highly optimized path in Mach. +On a 386 it's about two dozen instructions. +This is little worse than a +simple procedure call.) +<P> +Many features of Unix, such as signal masks and vectors, are handled +completely by the library. +This makes such features significantly cheaper +than in Unix. +It is now reasonable to use +<CODE>sigblock</CODE> +extensively to protect +critical sections, rather than seeking out some other, less expensive method. + +<H3>Network Protocols</H3> +<P> +The Hurd will have a library that will make it very easy to port 4.4 BSD +protocol stacks into the Hurd. +This will enable operation, virtually for +free, of all the protocols supported by BSD. +Currently, this includes the +CCITT protocols, the TCP/IP protocols, the Xerox NS protocols, and the ISO +protocols. +<P> +For optimal performance some work would be necessary to take advantage of +Hurd features that provide for very high speed I/O. +For most protocols this +will require some thought, but not too much time. +The Hurd will run the +TCP/IP protocols as efficiently as possible. +<P> +As an interesting example of the flexibility of the Hurd design, consider the +case of IP trailers, used extensively in BSD for performance. +While the Hurd +will be willing to send and receive trailers, it will gain fairly little +advantage in doing so because there is no requirement that data be copied and +avoiding copies for page-aligned data is irrelevant. diff --git a/hurd/documentation/hurd-talk.html b/hurd/documentation/hurd-talk.html new file mode 100644 index 00000000..d608e12a --- /dev/null +++ b/hurd/documentation/hurd-talk.html @@ -0,0 +1,1061 @@ +[[meta copyright="Copyright © 2001 Marcus Brinkmann"]] + +[[meta license="Verbatim copying and distribution of this entire article is +permitted in any medium, provided this notice is preserved."]] + +[[meta title="The Hurd, a presentation by Marcus Brinkmann"]] + + +<H4><A NAME="contents">Table of Contents</A></H4> +<UL> + <LI><A HREF="#int" NAME="TOCint">Introduction</A> + <LI><A HREF="#ove" NAME="TOCove">Overview</A> + <LI><A HREF="#his" NAME="TOChis">Historicals</A> + <LI><A HREF="#ker" NAME="TOCker">Kernel Architectures</A> + <LI><A HREF="#mic" NAME="TOCmic">Micro vs Monolithic</A> + <LI><A HREF="#sin" NAME="TOCsin">Single Server vs Multi Server</A> + <LI><A HREF="#mul" NAME="TOCmul">Multi Server is superior, ...</A> + <LI><A HREF="#the" NAME="TOCthe">The Hurd even more so.</A> + <LI><A HREF="#mac" NAME="TOCmac">Mach Inter Process Communication</A> + <LI><A HREF="#how" NAME="TOChow">How to get a port?</A> + <LI><A HREF="#exa" NAME="TOCexa">Example of <SAMP>hurd_file_name_lookup</SAMP></A> + <LI><A HREF="#pat" NAME="TOCpat">Pathname resolution example</A> + <LI><A HREF="#map" NAME="TOCmap">Mapping the POSIX Interface</A> + <LI><A HREF="#filser" NAME="TOCfilser">File System Servers</A> + <LI><A HREF="#act" NAME="TOCact">Active vs Passive</A> + <LI><A HREF="#aut" NAME="TOCaut">Authentication</A> + <LI><A HREF="#ope" NAME="TOCope">Operations on authentication ports</A> + <LI><A HREF="#est" NAME="TOCest">Establishing trusted connections</A> + <LI><A HREF="#pas" NAME="TOCpas">Password Server</A> + <LI><A HREF="#pro" NAME="TOCpro">Process Server</A> + <LI><A HREF="#filsys" NAME="TOCfilsys">Filesystems</A> + <LI><A HREF="#dev" NAME="TOCdev">Developing the Hurd</A> + <LI><A HREF="#sto" NAME="TOCsto">Store Abstraction</A> + <LI><A HREF="#deb" NAME="TOCdeb">Debian GNU/Hurd</A> + <LI><A HREF="#stabin" NAME="TOCstabin">Status of the Debian GNU/Hurd binary archive</A> + <LI><A HREF="#stainf" NAME="TOCstainf">Status of the Debian infrastructure</A> + <LI><A HREF="#staarc" NAME="TOCstaarc">Status of the Debian Source archive</A> + <LI><A HREF="#debide" NAME="TOCdebide">Debian GNU/Hurd: Good idea, bad idea?</A> + <LI><A HREF="#end" NAME="TOCend">End</A> +</UL> +<HR> +<H3>Talk about the Hurd</H3> +<P> +This talk about the Hurd was written by Marcus Brinkmann for +<UL> +<LI>OSDEM, Brussels, 4. Feb 2001, +<LI>Frühjahrsfachgespräche, Cologne, 2. Mar 2001 and +<LI>Libre Software Meeting, Bordeaux, 4. Jul 2001. +</UL> + +<H4><A HREF="#TOCint" NAME="int">Introduction</A></H4> +<P> +When we talk about free software, we usually refer to the free +software licenses. We also need relief from software patents, so our +freedom is not restricted by them. But there is a third type of +freedom we need, and that's user freedom. + +<P> +Expert users don't take a system as it is. They like to change the +configuration, and they want to run the software that works best for +them. That includes window managers as well as your favourite text +editor. But even on a GNU/Linux system consisting only of free +software, you can not easily use the filesystem format, network +protocol or binary format you want without special privileges. In +traditional unix systems, user freedom is severly restricted by the +system administrator. + +<P> +The Hurd removes these restrictions from the user. It provides an +user extensible system framework without giving up POSIX compatibility +and the unix security model. Throughout this talk, we will see that +this brings further advantages beside freedom. + +<H4><A HREF="#TOCove" NAME="ove">Overview</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> + +<P> +The Hurd is a POSIX compatible multi-server +system operating on top of the GNU Mach microkernel. + +<P> +Topics: +<UL> + <LI>GNU Mach</LI> + <LI>The Hurd</LI> + <LI>Development</LI> + <LI>Debian GNU/Hurd</LI> +</UL> +</TD></TR></TABLE> + +<P> +The Hurd is a POSIX compatible multi-server system operating on top of +the GNU Mach Microkernel. + +<P> +I will have to explain what GNU Mach is, so we start with that. Then +I will talk about the Hurd's architecture. After that, I will give a +short overview on the Hurd libraries. Finally, I will tell you how +the Debian project is related to the Hurd. + +<H4><A HREF="#TOChis" NAME="his">Historicals</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"> +<TR><TD VALIGN="TOP" ALIGN="LEFT"> +<UL> + <LI>1983: Richard Stallman founds the GNU project.</LI> + <LI>1988: Decision is made to use Mach 3.0 as the kernel.</LI> + <LI>1991: Mach 3.0 is released under compatible license.</LI> + <LI>1991: Thomas Bushnell, BSG, founds the Hurd project.</LI> + <LI>1994: The Hurd boots the first time.</LI> + <LI>1997: Version 0.2 of the Hurd is released.<BR><BR></LI> + <LI>1998: Debian hurd-i386 archive is created.</LI> + <LI>2001: Debian GNU/Hurd snapshot fills three CD images.</LI> +</UL> +</TD></TR></TABLE> + +<P> +When Richard Stallman founded the GNU project in 1983, he wanted to +write an operating system consisting only of free software. Very +soon, a lot of the essential tools were implemented, and released +under the GPL. However, one critical piece was missing: The kernel. +<P> +After considering several alternatives, it was decided not to write a +new kernel from scratch, but to start with the Mach microkernel. This +was in 1988, and it was not before 1991 that Mach was released under a +license allowing the GNU project to distribute it as a part of the +system. +<P> +In 1998, I started the Debian GNU/Hurd project, and in 2001 the number +of available GNU/Hurd packages fills three CD images. + +<H4><A HREF="#TOCker" NAME="ker">Kernel Architectures</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Microkernel: +<UL> + <LI>Enforces resource management (paging, scheduling)</LI> + <LI>Manages tasks</LI> + <LI>Implements message passing for IPC</LI> + <LI>Provides basic hardware support</LI> +</UL> +<P> +Monolithic kernel: +<UL> + <LI>No message passing necessary</LI> + <LI>Rich set of features (filesystems, authentication, network + sockets, POSIX interface, ...)</LI> +</UL> +</TD></TR></TABLE> +<P> +Microkernels were very popular in the scientific world around that +time. They don't implement a full operating system, but only the +infrastructure needed to enable other tasks to implement most +features. In contrast, monolithical kernels like Linux contain +program code of device drivers, network protocols, process management, +authentication, file systems, POSIX compatible interfaces and much +more. +<P> +So what are the basic facilities a microkernel provides? In general, +this is resource management and message passing. Resource management, +because the kernel task needs to run in a special privileged mode of +the processor, to be able to manipulate the memory management unit and +perform context switches (also to manage interrupts). Message +passing, because without a basic communication facility the other +tasks could not interact to provide the system services. Some +rudimentary hardware device support is often necessary to bootstrap +the system. So the basic jobs of a microkernel are enforcing the +paging policy (the actual paging can be done by an external pager +task), scheduling, message passing and probably basic hardware device +support. +<P> +Mach was the obvious choice back then, as it provides a rich set of +interfaces to get the job done. Beside a rather brain-dead device +interface, it provides tasks and threads, a messaging system allowing +synchronous and asynchronous operation and a complex interface for +external pagers. It's certainly not one of the sexiest microkernels +that exist today, but more like a big old mama. The GNU project +maintains its own version of Mach, called GNU Mach, which is based on +Mach 4.0. In addition to the features contained in Mach 4.0, the GNU +version contains many of the Linux 2.0 block device and network card +drivers. +<P> +A complete treatment of the differences between a microkernel and +monolithical kernel design can not be provided here. But a couple of +advantages of a microkernel design are fairly obvious. + +<H4><A HREF="#TOCmic" NAME="mic">Micro vs Monolithic</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Microkernel +<UL> + <LI>Clear cut responsibilities + <LI>Flexibility in operating system design, easier debugging</LI> + <LI>More stability (less code to break)</LI> + <LI>New features are not added to the kernel</LI> +</UL> +<P> +Monolithic kernel +<UL> + <LI>Intolerance or creeping featuritis</LI> + <LI>Danger of spaghetti code</LI> + <LI>Small changes can have far reaching side effects</LI> +</UL> +</TD></TR></TABLE> +<P> +Because the system is split up into several components, clean +interfaces have to be developed, and the responsibilities of each part +of the system must be clear. +<P> +Once a microkernel is written, it can be used as the base for several +different operating systems. Those can even run in parallel which +makes debugging easier. When porting, most of the hardware dependant +code is in the kernel. +<P> +Much of the code that doesn't need to run in the special kernel mode +of the processor is not part of the kernel, so stability increases +because there is simply less code to break. +<P> +New features are not added to the kernel, so there is no need to hold +the barrier high for new operating system features. +<P> +Compare this to a monolithical kernel, where you either suffer from +creeping featuritis or you are intolerant of new features (we see both +in the Linux kernel). +<P> +Because in a monolithical kernel, all parts of the kernel can access +all data structures in other parts, it is more likely that short cuts +are used to avoid the overhead of a clean interface. This leads to a +simple speed up of the kernel, but also makes it less comprehensible +and more error prone. A small change in one part of the kernel can +break remote other parts. + +<H4><A HREF="#TOCsin" NAME="sin">Single Server vs Multi Server</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Single Server +<UL> + <LI>A single task implements the functionality of the operating system.</LI> +</UL> +<P> +Multi Server +<UL> + <LI>Many tasks cooperate to provide the system's functionality.</LI> + <LI>One server provides only a small but well-defined part of the + whole system.</LI> + <LI>The responsibilities are distributed logically among the servers.</LI> +</UL> +<P> +A single-server system is comparable to a monolithic kernel system. It +has similar +advantages and disadvantages. +</TD></TR></TABLE> +<P> +There exist a couple of operating systems based on Mach, but they all +have the same disadvantages as a monolithical kernel, because those +operating systems are implemented in one single process running on top +of the kernel. This process provides all the services a monolithical +kernel would provide. This doesn't make a whole lot of sense (the +only advantage is that you can probably run several of such isolated +single servers on the same machine). Those systems are also called +single-server systems. The Hurd is the only usable multi-server +system on top of Mach. In the Hurd, there are many server programs, +each one responsible for a unique service provided by the operating +system. These servers run as Mach tasks, and communicate using the +Mach message passing facilities. One of them does only provide a +small part of the functionality of the system, but together they build +up a complete and functional POSIX compatible operating system. + +<H4><A HREF="#TOCmul" NAME="mul">Multi Server is superior, ...</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Any multi-server has advantages over single-server: +<UL> + <LI>Clear cut responsibilities</LI> + <LI>More stability: If one server dies, all others remain</LI> + <LI>Easier development cycle: Testing without reboot (or replacing + running servers), debugging with gdb</LI> + <LI>Easier to make changes and add new features +</UL> +</TD></TR></TABLE> +<P> +Using several servers has many advantages, if done right. If a file +system server for a mounted partition crashes, it doesn't take down +the whole system. Instead the partition is "unmounted", and +you can try to start the server again, probably debugging it this time +with gdb. The system is less prone to errors in individual +components, and over-all stability increases. The functionality of +the system can be extended by writing and starting new servers +dynamically. (Developing these new servers is easier for the reasons +just mentioned.) +<P> +But even in a multi-server system the barrier between the system and +the users remains, and special privileges are needed to cross it. We +have not achieved user freedom yet. + +<H4><A HREF="#TOCthe" NAME="the">The Hurd even more so.</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +The Hurd goes beyond all this, and allows users to write and run their +servers, too! +<UL> + <LI>Users can replace system servers dynamically with their own + implementations.</LI> + <LI>Users can decide what parts of the remainder of the system they + want to use.</LI> + <LI>Users can extend the functionality of the system.</LI> + <LI>No mutual trust necessary to make use of other users + services.</LI> + <LI>Security of the system is not harmed by trusting users + services.</LI> +</UL> +</TD></TR></TABLE> +<P> +To quote Thomas Bushnell, BSG, from his paper +[[``Towards_a_New_Strategy_of_OS_design''_(1996)|hurd-paper]]: +<BLOCKQUOTE> +The GNU Hurd, by contrast, is designed to make the area of system code +as limited as possible. Programs are required to communicate only +with a few essential parts of the kernel; the rest of the system is +replaceable dynamically. Users can use whatever parts of the +remainder of the system they want, and can easily add components +themselves for other users to take advantage of. No mutual trust need +exist in advance for users to use each other's services, nor does the +system become vulnerable by trusting the services of arbitrary users. +</BLOCKQUOTE> + +<P> +<EM>So the Hurd is a set of servers running on top of the Mach +micro-kernel, providing a POSIX compatible and extensible operating +system. What servers are there? What functionality do they provide, +and how do they cooperate?</EM> + +<H4><A HREF="#TOCmac" NAME="mac">Mach Inter Process Communication</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Ports are message queues which can be used as one-way communication +channels. +<UL> + <LI>Port rights are receive, send or send-once</LI> + <LI>Exactly one receiver</LI> + <LI>Potentially many senders</LI> +</UL> +<P> +MIG provides remote procedure calls on top of Mach IPC. RPCs look like +function calls to the user. +</TD></TR></TABLE> +<P> +Inter-process communication in Mach is based on the ports concept. A +port is a message queue, used as a one-way communication channel. In +addition to a port, you need a port right, which can be a send right, +receive right, or send-once right. Depending on the port right, you +are allowed to send messages to the server, receive messages from it, +or send just one single message. +<P> +For every port, there exists exactly one task holding the receive +right, but there can be no or many senders. The send-once right is +useful for clients expecting a response message. They can give a +send-once right to the reply port along with the message. The kernel +guarantees that at some point, a message will be received on the reply +port (this can be a notification that the server destroyed the +send-once right). +<P> +You don't need to know much about the format a message takes to be +able to use the Mach IPC. The Mach interface generator mig hides the +details of composing and sending a message, as well as receiving the +reply message. To the user, it just looks like a function call, but +in truth the message could be sent over a network to a server running +on a different computer. The set of remote procedure calls a server +provides is the public interface of this server. + + +<H4><A HREF="#TOChow" NAME="how">How to get a port?</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Traditional Mach: +<UL> + <LI>Nameserver provides ports to all registered servers.</LI> + <LI>The nameserver port itself is provided by Mach.</LI> + <LI>Like a phone book: One list.</LI> +</UL> +<P> +The Hurd: +<UL> + <LI>The filesystem is used as the server namespace.</LI> + <LI>Root directory port is inserted into each task.</LI> + <LI>The C library finds other ports with hurd_file_name_lookup, + performing a pathname resolution.</LI> + <LI>Like a tree of phone books.</LI> +</UL> +</TD></TR></TABLE> +<P> +So how does one get a port to a server? You need something like a +phone book for server ports, or otherwise you can only talk to +yourself. In the original Mach system, a special nameserver is +dedicated to that job. A task could get a port to the nameserver from +the Mach kernel and ask it for a port (with send right) to a server +that registered itself with the nameserver at some earlier time. +<P> +In the Hurd, there is no nameserver. Instead, the filesystem is used +as the server namespace. This works because there is always a root +filesystem in the Hurd (remember that the Hurd is a POSIX compatible +system); this is an assumption the people who developed Mach couldn't +make, so they had to choose a different strategy. You can use the +function hurd_file_name_lookup, which is part of the C library, to get +a port to the server belonging to a filename. Then you can start to +send messages to the server in the usual way. + +<H4><A HREF="#TOCexa" NAME="exa">Example of <SAMP>hurd_file_name_lookup</SAMP></A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"><PRE> +mach_port_t identity; +mach_port_t pwserver; +kern_return_t err; + +pwserver = hurd_file_name_lookup + ("/servers/password"); + +err = password_check_user (pwserver, + 0 /* root */, "supass", + &identity); +</PRE></TD></TR></TABLE> +<P> +As a concrete example, the special filename +<SAMP>/servers/password</SAMP> can be used to request a port to the +Hurd password server, which is responsible to check user provided +passwords. +<P> +(explanation of the example) + +<H4><A HREF="#TOCpat" NAME="pat">Pathname resolution example</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Task: Lookup /mnt/readme.txt where /mnt has a mounted filesystem. +<UL> + <LI>The C library asks the root filesystem server about + <SAMP>/mnt/readme.txt</SAMP>.</LI> + <LI>The root filesystem returns a port to the mnt filesystem server + (matching <SAMP>/mnt</SAMP>) and the retry name + <SAMP>/readme.txt</SAMP>.</LI> + <LI>The C library asks the mnt filesystem server about + <SAMP>/readme.txt</SAMP>.</LI> + <LI>The mnt filesystem server returns a port to itself and records + that this port refers to the regular file + <SAMP>/readme.txt</SAMP>.</LI> +</UL> +</TD></TR></TABLE> +<P> +The C library itself does not have a full list of all available +servers. Instead pathname resolution is used to traverse through a +tree of servers. In fact, filesystems themselves are implemented by +servers (let us ignore the chicken and egg problem here). So all the +C library can do is to ask the root filesystem server about the +filename provided by the user (assuming that the user wants to resolve +an absolute path), using the <SAMP>dir_lookup</SAMP> RPC. If the +filename refers to a regular file or directory on the filesystem, the +root filesystem server just returns a port to itself and records that +this port corresponds to the file or directory in question. But if a +prefix of the full path matches the path of a server the root +filesystem knows about, it returns to the C library a port to this +server and the remaining part of the pathname that couldn't be +resolved. The C library than has to retry and query the other server +about the remaining path component. Eventually, the C library will +either know that the remaining path can't be resolved by the last +server in the list, or get a valid port to the server in question. + +<H4><A HREF="#TOCmap" NAME="map">Mapping the POSIX Interface</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<TABLE BORDER="0" CELLPADDING="10"> +<TR> +<TH>Filedescriptor</TH> +<TH>Port to server providing the file</TH> +</TR><TR> +<TD VALIGN="TOP" ALIGN="LEFT"><SAMP>fd = open(name,...)</SAMP></TD> +<TD VALIGN="TOP" +ALIGN="LEFT"><SAMP>dir_lookup(..,name,..,&port)</SAMP><BR> +[pathname resolution]</TD> +</TR><TR> +<TD VALIGN="TOP" ALIGN="LEFT"><SAMP>read(fd, ...)</SAMP></TD> +<TD VALIGN="TOP" ALIGN="LEFT"><SAMP>io_read(port, ...)</SAMP></TD> +</TR><TR> +<TD VALIGN="TOP" ALIGN="LEFT"><SAMP>write(fd, ...)</SAMP></TD> +<TD VALIGN="TOP" ALIGN="LEFT"><SAMP>io_write(port, ...)</SAMP></TD> +</TR><TR> +<TD VALIGN="TOP" ALIGN="LEFT"><SAMP>fstat(fd, ...)</SAMP></TD> +<TD VALIGN="TOP" ALIGN="LEFT"><SAMP>io_stat(port, ...)</SAMP></TD> +</TR><TR> +<TD VALIGN="TOP" ALIGN="LEFT">...</TD><TD></TD> +</TR> +</TABLE> +</TD></TR></TABLE> +<P> +It should by now be obvious that the port returned by the server can +be used to query the files status, content and other information from +the server, if good remote procedure calls to do that are defined and +implemented by it. This is exactly what happens. Whenever a file is +opened using the C libraries <SAMP>open()</SAMP> call, the C library +uses the above pathname resolution to get a port to a server providing +the file. Then it wraps a file descriptor around it. So in the Hurd, +for every open file descriptor there is a port to a server providing +this file. Many other C library calls like <SAMP>read()</SAMP> and +<SAMP>write()</SAMP> just call a corresponding RPC using the port +associated with the file descriptor. + +<H4><A HREF="#TOCfilser" NAME="filser">File System Servers</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<UL> + <LI>Provide file and directory services for ports (and more).</LI> + <LI>These ports are returned by a directory lookup.</LI> + <LI>Translate filesystem accesses through their root path (hence the + name translator).</LI> + <LI>The C library maps the POSIX file and directory interface (and + more) to RPCs to the filesystem servers ports, but also does work on + its own.</LI> + <LI>Any user can install file system servers on inodes they own.</LI> +</UL> +</TD></TR></TABLE> +<P> +So we don't have a single phone book listing all servers, but rather a +tree of servers keeping track of each other. That's really like +calling your friend and asking for the phone number of the blond girl +at the party yesterday. He might refer you to a friend who hopefully +knows more about it. Then you have to retry. +<P> +This mechanism has huge advantages over a single nameserver. First, +note that standard unix permissions on directories can be used to +restrict access to a server (this requires that the filesystems +providing those directories behave). You just have to set the +permissions of a parent directory accordingly and provide no other way +to get a server port. +<P> +But there are much deeper implications. Most of all, a pathname never +directly refers to a file, it refers to a port of a server. That +means that providing a regular file with static data is just one of +the many options the server has to service requests on the file port. +A server can also create the data dynamically. For example, a server +associated with <SAMP>/dev/random</SAMP> can provide new random data +on every <SAMP>io_read()</SAMP> on the port to it. A server +associated with <SAMP>/dev/fortune</SAMP> can provide a new fortune +cookie on every <SAMP>open()</SAMP>. +<P> +While a regular filesystem server will just serve the data as stored +in a filesystem on disk, there are servers providing purely virtual +information, or a mixture of both. It is up to the server to behave +and provide consistent and useful data on each remote procedure call. +If it does not, the results may not match the expectations of the user +and confuse him. +<P> +A footnote from the Hurd info manual: +<BLOCKQUOTE> +(1) You are lost in a maze of twisty little filesystems, all +alike.... +</BLOCKQUOTE> +<P> +Because a server installed in the filesystem namespace translates all +filesystem operations that go through its root path, such a server is +also called "active translator". You can install translators using +the settrans command with the <SAMP>-a</SAMP> option. + +<H4><A HREF="#TOCact" NAME="act">Active vs Passive</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Active Translators: +<UL> + <LI>"<SAMP>settrans -a /cdrom /hurd/isofs /dev/hd2</SAMP>"</LI> + <LI>Are running filesystem servers.</LI> + <LI>Are attached to the root node they translate.</LI> + <LI>Run as a normal process.</LI> + <LI>Go away with every reboot, or even time out.</LI> +</UL> +</TD></TR></TABLE> +<P> +Many translator settings remain constant for a long time. It would be +very lame to always repeat the same couple of dozens settrans calls +manually or at boot time. So the Hurd provides a filesystem extension +that allows to store translator settings inside the filesystem and let +the filesystem servers do the work to start those servers on demand. +Such translator settings are called "passive translators". A passive +translator is really just a command line string stored in an inode of +the filesystem. If during a pathname resolution a server encounters +such a passive translator, and no active translator does exist already +(for this node), it will use this string to start up a new translator +for this inode, and then let the C library continue with the path +resolution as described above. Passive translators are installed with +settrans using the <SAMP>-p</SAMP> option (which is already the +default). + +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Passive Translators: +<UL> + <LI>"<SAMP>settrans /mnt /hurd/ext2fs /dev/hd1s1</SAMP>"</LI> + <LI>Are stored as command strings into an inode.</LI> + <LI>Are used to start a new active translator if there isn't + one.</LI> + <LI>Startup is transparent to the user.</LI> + <LI>Startup happens the first time the server is needed.</LI> + <LI>Are permanent across reboots (like file data).</LI> +</UL> +</TD></TR></TABLE> +<P> +So passive translators also serve as a sort of automounting feature, +because no manual interaction is required. The server start up is +deferred until the service is need, and it is transparent to the user. +<P> +When starting up a passive translator, it will run as a normal process +with the same user and group id as those of the underlying inode. Any +user is allowed to install passive and active translators on inodes +that he owns. This way the user can install new servers into the +global namespace (for example, in his home or tmp directory) and thus +extend the functionality of the system (recall that servers can +implement other remote procedure calls beside those used for files and +directories). A careful design of the trusted system servers makes +sure that no permissions leak out. +<P> +In addition, users can provide their own implementations of some of +the system servers instead the system default. For example, they can +use their own exec server to start processes. The user specific exec +server could for example start java programs transparently (without +invoking the interpreter manually). This is done by setting the +environment variable <SAMP>EXECSERVERS</SAMP>. The systems default +exec server will evaluate this environment variable and forward the +RPC to each of the servers listed in turn, until some server accepts +it and takes over. The system default exec server will only do this +if there are no security implications. (XXX There are other ways to +start new programs than by using the system exec server. Those are +still available.) +<P> +Let's take a closer look at some of the Hurd servers. It was already +mentioned that only few system servers are mandatory for users. To +establish your identity within the Hurd system, you have to +communicate with the trusted systems authentication server +<SAMP>auth</SAMP>. To put the system administrator into control over +the system components, the process server does some global +bookkeeping. +<P> +But even these servers can be ignored. However, registration with the +authentication server is the only way to establish your identity +towards other system servers. Likewise, only tasks registered as +processes with the process server can make use of its services. + +<H4><A HREF="#TOCaut" NAME="aut">Authentication</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +A user identity is just a port to an authserver. The auth server +stores four set of ids for it: +<UL> + <LI>effective user ids</LI> + <LI>effective group ids</LI> + <LI>available user ids</LI> + <LI>available group ids</LI> +</UL> +<P> +Basic properties: +<UL> + <LI>Any of these can be empty.</LI> + <LI>A 0 among the user ids identifies the superuser.</LI> + <LI>Effective ids are used to check if the user has the + permission.</LI> + <LI>Available ids can be turned into effective ids on user + request.</LI> +</UL> +</TD></TR></TABLE> +<P> +The Hurd auth server is used to establish the identity of a user for a +server. Such an identity (which is just a port to the auth server) +consists of a set of effective user ids, a set of effective group ids, +a set of available user ids and a set of available group ids. Any of +these sets can be empty. + +<H4><A HREF="#TOCope" NAME="ope">Operations on authentication ports</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +The auth server provides the following operations on ports: +<UL> + <LI>Merge the ids of two ports into a new one.</LI> + <LI>Return a new port containing a subset of the ids in a port.</LI> + <LI>Create a new port with arbitrary ids (superuser only).</LI> + <LI>Establish a trusted connection between users and servers.</LI> +</UL> +</TD></TR></TABLE> +<P> +If you have two identities, you can merge them and request an identity +consisting of the unions of the sets from the auth server. You can +also create a new identity consisting only of subsets of an identity +you already have. What you can't do is extending your sets, unless +you are the superuser which is denoted by having the user id 0. + +<H4><A HREF="#TOCest" NAME="est">Establishing trusted connections</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<UL> + <LI>User provides a rendezvous port to the server (with + <SAMP>io_reauthenticate</SAMP>).</LI> + <LI>User calls <SAMP>auth_user_authenticate</SAMP> on the + authentication port (his identity), passing the rendezvous port.</LI> + <LI>Server calls <SAMP>auth_server_authenticate</SAMP> on its + authentication port (to a trusted auth server), passing the + rendezvous port and the server port.</LI> + <LI>If both authentication servers are the same, it can match the + rendezvous ports and return the server port to the user and the user + ids to the server.</LI> +</UL> +</TD></TR></TABLE> +<P> +Finally, the auth server can establish the identity of a user for a +server. This is done by exchanging a server port and a user identity +if both match the same rendezvous port. The server port will be +returned to the user, while the server is informed about the id sets +of the user. The server can then serve or reject subsequent RPCs by +the user on the server port, based on the identity it received from +the auth server. +<P> +Anyone can write a server conforming to the auth protocol, but of +course all system servers use a trusted system auth server to +establish the identity of a user. If the user is not using the system +auth server, matching the rendezvous port will fail and no server port +will be returned to the user. Because this practically requires all +programs to use the same auth server, the system auth server is +minimal in every respect, and additional functionality is moved +elsewhere, so user freedom is not unnecessarily restricted. + +<H4><A HREF="#TOCpas" NAME="pas">Password Server</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +The password server <SAMP>/servers/password</SAMP> runs as root and +returns a new authentication port in exchange for a unix password. +<P> +The ids corresponding to the authentication port match the unix user +and group ids. +<P> +Support for shadow passwords is implemented here. +</TD></TR></TABLE> +<P> +The password server sits at <SAMP>/servers/password</SAMP> and runs as +root. It can hand out ports to the auth server in exchange for a unix +password, matching it against the password or shadow file. Several +utilities make use of this server, so they don't need to be setuid +root. + +<H4><A HREF="#TOCpro" NAME="pro">Process Server</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +The superuser must remain control over user tasks, so: +<UL> + <LI>All mach tasks are associated with a PID in the system default + proc server.</LI> +</UL> +<P> +Optionally, user tasks can store: +<UL> + <LI>Their environment variables.</LI> + <LI>Their argument vector.</LI> + <LI>A port, which others can request based on the PID (like a + nameserver).</LI> +</UL> +<P> +Also implemented in the proc server: +<UL> + <LI>Sessions and process groups.</LI> + <LI>Global configuration not in Mach, like hostname, hostid, system + version.</LI> +</UL> +</TD></TR></TABLE> +<P> +The process server is responsible for some global bookkeeping. As +such it has to be trusted and is not replaceable by the user. +However, a user is not required to use any of its service. In that +case the user will not be able to take advantage of the POSIXish +appearance of the Hurd. +<P> +The Mach Tasks are not as heavy as POSIX processes. For example, +there is no concept of process groups or sessions in Mach. The proc +server fills in the gap. It provides a PID for all Mach tasks, and +also stores the argument line, environment variables and other +information about a process (if the mach tasks provide them, which is +usually the case if you start a process with the default +<SAMP>fork()</SAMP>/<SAMP>exec()</SAMP>). A process can also register +a message port with the proc server, which can then be requested by +anyone. So the proc server also functions as a nameserver using the +process id as the name. +<P> +The proc server also stores some other miscellaneous information not +provided by Mach, like the hostname, hostid and system version. +Finally, it provides facilities to group processes and their ports +together, as well as to convert between pids, process server ports and +mach task ports. +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +User tasks not registering themselve with proc only have a PID assigned. +<P> +Users can run their own proc server in addition to the system default, +at least for those parts of the interface that don't require superuser +privileges. +</TD></TR></TABLE> +<P> +Although the system default proc server can't be avoided (all Mach +tasks spawned by users will get a pid assigned, so the system +administrator can control them), users can run their own additional +process servers if they want, implementing the features not requiring +superuser privileges. + +<H4><A HREF="#TOCfilsys" NAME="filsys">Filesystems</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Store based filesystems +<UL> + <LI><SAMP>ext2fs</SAMP></LI> + <LI><SAMP>ufs</SAMP></LI> + <LI><SAMP>isofs</SAMP> (iso9660, RockRidge, GNU extensions)</LI> + <LI><SAMP>fatfs</SAMP> (under development)</LI> +</UL> +<P> +Network file systems +<UL> + <LI><SAMP>nfs</SAMP></LI> + <LI><SAMP>ftpfs</SAMP></LI> +</UL> +<P> +Miscellaneous +<UL> + <LI><SAMP>hostmux</SAMP></LI> + <LI><SAMP>usermux</SAMP></LI> + <LI><SAMP>tmpfs</SAMP> (under development)</LI> +</UL> +</TD></TR></TABLE> +<P> +We already talked about translators and the file system service they +provide. Currently, we have translators for the ext2, ufs and iso9660 +filesystems. We also have an nfs client and an ftp filesystem. +Especially the latter is intriguing, as it provides transparent access +to ftp servers in the filesystem. Programs can start to move away +from implementing a plethora of network protocols, as the files are +directly available in the filesystem through the standard POSIX file +interface. + + +<H4><A HREF="#TOCdev" NAME="dev">Developing the Hurd</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Over a dozen libraries support the development of new servers. +<P> +For special server types highly specialized +libraries require only the implementation of a +number of callback functions. +<UL> + <LI>Use <SAMP>libdiskfs</SAMP> for store based filesystems.</LI> + <LI>Use <SAMP>libnetfs</SAMP> for network filesystems, also for + virtual filesystems.</LI> + <LI>Use <SAMP>libtrivfs</SAMP> for simple filesystems providing only + a single file or directory.</LI> +</UL> +</TD></TR></TABLE> +<P> +The Hurd server protocols are complex enough to allow for the +implementation of a POSIX compatible system with GNU extensions. +However, a lot of code can be shared by all or at least similar +servers. For example, all storage based filesystems need to be able to +read and write to a store medium splitted in blocks. The Hurd comes +with several libraries which make it easy to implement new servers. +Also, there are already a lot of examples of different server types in +the Hurd. This makes writing a new server easier. +<P> +<SAMP>libdiskfs</SAMP> is a library that supports writing store based +filesystems like ext2fs or ufs. It is not very useful for filesystems +which are purely virtual, like <SAMP>/proc</SAMP> or files in +<SAMP>/dev</SAMP>. +<P> +<SAMP>libnetfs</SAMP> is intended for filesystems which provide a rich +directory hierarchy, but don't use a backing store (for example ftpfs, +nfs). +<P> +<SAMP>libtrivfs</SAMP> is intended for filesystems which just provide +a single inode or directory. Most servers which are not intended to +provide a filesystem but other services (like +<SAMP>/servers/password</SAMP>) use it to provide a dummy file, so +that file operations on the servers node will not return errors. But +it can also be used to provide meaningful data in a single file, like +a device store or a character device. + +<H4><A HREF="#TOCsto" NAME="sto">Store Abstraction</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Another very useful library is libstore, which is used by all store +based filesystems. It provides a store media abstraction. A store +consists of a store class and a name (which itself can sometimes +contain stores). +<P> +Primitive store classes: +<UL> + <LI>device store like device:hd2, device:hd0s1, device:fd0</LI> + <LI>file store like file:/tmp/disk_image</LI> + <LI>task store like task:PID</LI> + <LI>zero store like zero:4m (like /dev/zero, of size 4 MB)</LI> +</UL> +</TD></TR></TABLE> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Composed store classes: +<UL> + <LI>copy store like copy:zero:4m</LI> + <LI>gunzip/bunzip2 store like gunzip:device:fd0</LI> + <LI>concat store like concat:device:hd0s2:device:hd1s5</LI> + <LI>ileave store (RAID-0(2))</LI> + <LI>remap store like remap:10+20,50+:file:/tmp/blocks</LI> + <LI>...</LI> +</UL> +<P> +Wanted: A similar abstraction for streams (based on channels), which +can be used by network and character device servers. +</TD></TR></TABLE> +<P> +<SAMP>libstore</SAMP> provides a store abstraction, which is used by +all store based filesystems. The store is determined by a type and a +name, but some store types modify another store rather than providing +a new store, and thus stores can be stacked. For example, the device +store type expects a Mach device, but the remap store expects a list +of blocks to pick from another store, like remap:1+:device:hd2, which +would pick all blocks from hd2 but the first one, which skipped. +Because this functionality is provided in a library, all libstore +using filesystems support many different store kinds, and adding a new +store type is enough to make all store based filesystems support it. + +<H4><A HREF="#TOCdeb" NAME="deb">Debian GNU/Hurd</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Goal: +<UL> + <LI>Provide a binary distribution of the Hurd that is easy to + install.</LI> +</UL> +<P> +Constraints: +<UL> + <LI>Use the same source packages as Debian GNU/Linux.</LI> + <LI>Use the same infrastructure: + <UL> + <LI>Policy</LI> + <LI>Archive</LI> + <LI>Bug tracking system</LI> + <LI>Release process</LI> + </UL></LI> +</UL> +<P> +Side Goal: +<UL> + <LI>Prepare Debian for the future: + <UL> + <LI>More flexibility in the base system</LI> + <LI>Identify dependencies on the Linux kernel</LI> + </UL></LI> +</UL> +</TD></TR></TABLE> +<P> +The Debian distribution of the GNU Hurd that I started in 1998 is +supposed to become a complete binary distribution of the Hurd that is +easy to install. + +<H4><A HREF="#TOCstabin" NAME="stabin">Status of the Debian GNU/Hurd binary archive</A></H4> +<P> +See +<A HREF="http://buildd.debian.org/stats/graph.png">http://buildd.debian.org/stats/graph.png</A> +for the most current version of the statistic. + +<H4><A HREF="#TOCstainf" NAME="stainf">Status of the Debian infrastructure</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Plus: +<UL> + <LI>Source packages can identify build and host OS using + dpkg-architecture.</LI> +</UL> +<P> +Minus: +<UL> + <LI>The binary architecture field is insufficient.</LI> + <LI>The BTS has no architecture tag.</LI> + <LI>The policy/FHS need (small) Hurd specific extensions.</LI> +</UL> +</TD></TR></TABLE> +<P> +While good compatibiity can be achieved at the source level, +the binary packages can not always express their relationship +to the available architectures sufficiently. +<P> +For example, the Linux version of makedev is binary-all, where +a binary-all-linux relationship would be more appropriate. +<P> +More work has to be done here to fix the tools. + +<H4><A HREF="#TOCstaarc" NAME="staarc">Status of the Debian Source archive</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<UL> + <LI>Most packages just work.</LI> + <LI>Maintainers are usually responsive and cooperative.</LI> + <LI>Turtle, the autobuilder, crunches through the whole list right + now.</LI> +</UL> +<P> +Common pitfalls are POSIX incompatibilities: +<UL> + <LI>Upstream: + <UL> + <LI>Unconditional use of <SAMP>PATH_MAX</SAMP> + (<SAMP>MAXPATHLEN</SAMP>), <SAMP>MAXHOSTNAMELEN</SAMP>.</LI> + <LI>Unguarded use of Linux kernel features.</LI> + <LI>Use of legacy interfaces (<SAMP>sys_errlist</SAMP>, + <SAMP>termio</SAMP>).</LI> + </UL></LI> + <LI>Debian: + <UL> + <LI>Unguarded activation of extensions available with Linux.</LI> + <LI>Low quality patches.</LI> + <LI>Assuming GNU/Linux in package scripts.</LI> + </UL></LI> +</UL> +</TD></TR></TABLE> +<P> +Most packages are POSIX compatible and can be compiled without +changes on the Hurd. The maintainers of the Debian source packages +are usually very kind, responsiver and helpful. +<P> +The Turtle autobuilder software (<A +HREF="http://turtle.sourceforge.net" >http://turtle.sourceforge.net</A>) +builds the Debian packages on the Hurd automatically. + +<H4><A HREF="#TOCdebide" NAME="debide">Debian GNU/Hurd: Good idea, bad idea?</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Upstream benefits: +<UL> + <LI>Software packages become more portable.</LI> +</UL> +<P> +Debian benefits: +<UL> + <LI>Debian becomes more portable.</LI> + <LI>Maintainers learn about portability and other systems.</LI> + <LI>Debian gets a lot of public recognition.</LI> +</UL> +<P> +GNU/Hurd benefits: +<UL> + <LI>Large software base.</LI> + <LI>Great infrastructure.</LI> + <LI>Nice community to partner with.</LI> +</UL> +</TD></TR></TABLE> +<P> +The sheet lists the advantages of all groups involved. + +<H4><A HREF="#TOCend" NAME="end">End</A></H4> +<TABLE BORDER="1" CELLPADDING="5" WIDTH="100%"><TR><TD VALIGN="TOP" ALIGN="LEFT"> +<P> +Join us at +<UL> + <LI><A HREF="http://hurd.gnu.org/" >http://hurd.gnu.org/</A></LI> + <LI><A HREF="http://www.debian.org/ports/hurd" + >http://www.debian.org/ports/hurd</A></LI> + <LI><A HREF="http://www.hurdfr.org" + >http://www.hurdfr.org</A></LI> +</UL> +</TD></TR></TABLE> +<P> +List of contacts. diff --git a/hurd/documentation/translators.html b/hurd/documentation/translators.html new file mode 100644 index 00000000..4e47a9c0 --- /dev/null +++ b/hurd/documentation/translators.html @@ -0,0 +1,236 @@ +[[meta copyright="Copyright © 1998, 1999, 2007, 2008 Free Software Foundation, +Inc."]] + +[[meta license="Verbatim copying and distribution of this entire article is +permitted in any medium, provided this notice is preserved."]] + +[[meta title="Translators"]] + +By Marcus Brinkmann. + +<ul> +<li><a href="#concept" name="TOC_concept">Concept</a></li> +<li><a href="#examples" name="TOC_examples">Examples</a></li> +<li><a href="#actpas" name="TOC_actpas">Passive Translators, Active Translators</a></li> +<li><a href="#manage" name="TOC_manage">Managing Translators</a></li> +</ul> +<h3><a href="#TOC_concept" name="concept">Concept</a></h3> +<p> +Before we take a closer look at translators, let us consider regular +filesystems. A filesystem is store for a hierarchical tree of directories +and files. You access directories and files by a special character string, +the path. Furthermore, there are symbolic links to refer to one file at +several places in the tree, there are hard links to give one and the same +file several names. There are also special device files for communication +with the hardware device drivers of the kernel, and there are mount points +to include other stores in the directory tree. Then there are obscure +objects like fifos and hard links.</p> +<p> +Although these objects are very different, they share some common +properties, for example, they have all an owner and a group associated with +them as well as access rights (permissions). This information is written in +inodes. This is a actually a further commonality: Every object has exactly +one inode associated with it (hard links are somewhat special as they share +one and the same inode). Sometimes, the inode has further information +stored in it. For example, the inode can contain the target of a symbolic +link.</p> +<p> +However, these commonalities are usually not exploited in the +implementations, despite the common programming interface to them. All +inodes can be accessed through the standard POSIX calls, for example +<code>read()</code> and <code>write()</code>. For example, to add a new +object type (for example a new link type) to a common monolithic unix +kernel, you would need to modify the code for each filesystem +seperately.</p> +<p> +In the Hurd, things work differently. Although in the Hurd a special +filesystem server can exploit special properties of standard object types +like links (in the ext2 filesystem with fast links, for example), it has a +general interface to add such features without modifying existing code.</p> +<p> +The trick is to allow a program to be inserted between the actual content of +a file and the user accessing this file. Such a program is called a +translator, because it is able to process the incoming requests in many +different ways. In other words, a translator is a Hurd server which provides +the basic filesystem interface.</p> +<p> +Translators have very interesting properties. From the kernels point of +view, they are just another user process. This means, translators can be run +by any user. You don't need root priviligies to install or modify a +translator, you only need the access rights for the underlying inode the +translator is attached to. Many translators don't require an actual file to +operate, they can provide information by their own means. This is why +the information about translators is stored in the inode.</p> +<p> +Translators are responsible to serve all file system operations that involve +the inode they are attached to. Because they are not restricted to the usual +set of objects (device file, link etc), they are free to return anything +that makes sense to the programmer. One could imagine a translator that +behaves like a directory when accessed by <code>cd</code> or +<code>ls</code> and at the same time behaves like a file when accessed by +<code>cat</code>.</p> +<h3><a href="#TOC_examples" name="examples">Examples</a></h3> +<h4>Mount Points</h4> +<p> +A mount point can be seen as an inode that has a special translator attached +to it. Its purpose would be to translate filesystem operations on the mount +point in filesystem operations on another store, let's say, another +partition.</p> +<p> +Indeed, this is how filesystems are implemented under the Hurd. A +filesystem is a translator. This translator takes a store as its argument, +and is able to serve all filesystem operations transparently.</p> +<h4>Device Files</h4> +<p> +There are many different device files, and in systems with a monolithical +kernel, they are all provided by the kernel itself. In the Hurd, all device +files are provided by translators. One translator can provide support for +many similar device files, for example all hard disk partitions. This way, +the number of actual translators needed is quite small. However, note that +for each device file accessed, a seperate translator task is started. +Because the Hurd is heavily multi threaded, this is very cheap.</p> +<p> +When hardware is involved, a translator usually starts to communicate with +the kernel to get the data from the hardware. However, if no hardware access +is necessary, the kernel does not need to be involved. For example, +<code>/dev/zero</code> does not require hardware access, and can therefore +be implemented completely in user space.</p> +<h4>Symbolic Links</h4> +<p> +A symbolic link can be seen as a translator. Accesing the symbolic link +would start up the translator, which would forward the request to the +filesystem that contains the file the link points to.</p> +<p> +However, for better performance, filesystems that have native support +for symbolic links can take advantage of this feature and implement +symbolic links differently. Internally, accessing a symbolic link would not +start a new translator process. However, to the user, it would still look +as if a passive translator is involved (see below for an explanation what a +passsive translator is).</p> +<p> +Because the Hurd ships with a symlink translator, any filesystem server that +provides support for translators automatically has support for symlinks (and +firmlinks, and device files etc)! This means, you can get a working +filesystem very fast, and add native support for symlinks and other features +later.</p> +<h3><a href="#TOC_actpas" name="actpas">Passive Translators, Active Translators</a></h3> +<p> +There are two types of translators, passive and active. They are really +completely different things, so don't mix them up, but they have a close +relation to each other.</p> +<h4>Active Translators</h4> +<p> +An active translator is a running translator process, as introduced above. +You can set and remove active translators using the +<code>settrans -a</code></a> +command. The <code>-a</code> option is necessary to tell +<code>settrans</code> that you want to modify the active translator.</p> +<p> +The <code>settrans</code> command takes three kind of arguments. First, you +can set options for the <code>settrans</code> command itself, like +<code>-a</code> to modify the active translator. Then you set the inode you +want to modify. Remember that a translator is always associated with an +inode in the directory hierarchy. You can only modify one inode at a time. +If you do not specify any more arguments, <code>settrans</code> will try to +remove an existing translator. How hard it tries depends on the force +options you specify (if the translator is in use by any process, you will +get "device or resource busy" error message unless you force it to go away).</p> +<p> +But if you specify further arguments, it will be interpreted as a command +line to run the translator. This means, the next argument is the filename of +the translator executable. Further arguments are options to the translator, +and not to the <code>settrans</code> command.</p> +<p> +For example, to mount an ext2fs partition, you can run +<code>settrans -a -c /mnt /hurd/ext2fs /dev/hd2s5</code>. The +<code>-c</code> option will create the mount point for you if it doesn't +exist already. This does not need to be a directory, by the way. To unmount, +you would try <code>settrans -a /mnt</code>.</p> +<h4>Passive Translators</h4> +<p> +A passive translator is set and modified with the same syntax as the active +translator (just leave away the <code>-a</code>, so everything said above is +true for passive translators, too. However, there is a difference: passive +translators are not yet started.</p> +<p> +This makes sense, because this is what you usually want. You don't want the +partition mounted unless you really access files on this partition. You +don't want to bring up the network unless there is some traffic and so +on.</p> +<p> +Instead, the first time the passive translator is accessed, it is +automatically read out of the inode and an active translator is started on +top of it using the command line that was stored in the inode. This is +similar to the Linux automounter functionality. However, it does not come as +an additional bonus that you have to set up manually, but an integral part of +the system. So, setting passive translators defers starting the translator +task until you really need it. By the way, if the active translator dies for +some reason, the next time the inode is accessed the translator is +restarted.</p> +<p> +There is a further difference: active translators can die or get lost. As +soon as the active translator process is killed (for example, because you +reboot the machine) it is lost forever. Passive translators are not transient +and stay in the inode during reboots until you modify them with the +<code>settrans</code> program or delete the inodes they are attached to. +This means, you don't need to maintain a configuration file with your mount +points.</p> +<p> +One last point: Even if you have set a passive translator, you can still +set a different active translator. Only if the translator is automatically +started because there was no active translator the time the inode was +accessed the passive translator is considered.</p> +<h3><a href="#TOC_manage" name="manage">Managing Translators</a></h3> +<p> +As mentioned above, you can use +<code>settrans</code></a> +to set and alter passive and active translators. There are a lot of options +to change the behaviour of <code>settrans</code> in case something goes +wrong, and to conditionalize its action. Here are some common usages:</p> +<ul><li><code>settrans -c /mnt /hurd/ext2fs /dev/hd2s5</code> mounts a +partition, the translator will stay across reboots.</li> +<li><code>settrans -a /mnt /hurd/ext2fs ~/dummy.fs</code> mounts a +filesystem inside a data file, the translator will go away if it dies.</li> +<li><code>settrans -fg /nfs-data</code> forces a translator to go away.</li> +</ul> +<p> +You can use the <code>showtrans</code></a> +command to see if a translator is attached to an inode. This will only show +you the passive translator though.</p> +<p> +You can change the options of an active (filesystem) translator with +<code>fsysopts</code> without actually restarting it. This is very +convenient. For example, you can do what is called "remounting a +partition read-only" under Linux simply by running <code>fsysopts +/mntpoint --readonly</code>. The running active translator +will change its behaviour according to your request if possible. +<code>fsysopts /mntpoint</code> without a parameter shows you the current +settings.</p> +<h4>Examples</h4> +<p> +I recommend that you start by reading the <code>/bin/mount</code> command, +it is only a small script. Because setting filesystem translators is +similar to mounting partitions, you can easily grasp the concept this way. +Make a file system image with <code>dd if=/dev/zero of=dummy.fs bs=1024k +count=8; mke2fs dummy.fs</code> and "mount" it with <code>settrans -c dummy +/hurd/ext2fs `pwd`/dummy.fs</code>. Note that the translator is not started +yet, no new <code>ext2fs</code> process is running (verify with <code>ps +Aux</code>). Check that everything is correct using <code>showtrans</code></p> +<p> +Now type <code>ls dummy</code> and you will notice the short delay that +occurs while the translator is started. After that, there will be no more +delays accessing dummy. Under Linux, one would say that you automounted a +loop file system. Check with <code>ps Aux</code> that there is an <code>ext2fs +dummy</code> process up and running now. Now put some files into the new +directory. Try to make the filesystem read-only with <code>fsysopts</code>. +Note how further write attempts fail now. Try to kill the active translator +with <code>settrans -g</code>.</p> +<p> +You should have some understanding of what is going on now. Now remember +that this was only <em>one</em> special server, the Hurd ext2fs server. +There are many more server in the <code>hurd</code> directory. Some of them +are for filesystems. Some are needed for file system features like links. +Some are needed for device files. Some are useful for networking. Imagine +"mounting" an FTP Server with <code>settrans</code> and downloading files +simply with the standard <code>cp</code> command. Or editing your web sites +with <code>emacs /ftp/homepage.my.server.org/index.html</code>!</p> diff --git a/hurd/faq/old_hurd_faq.txt b/hurd/faq/old_hurd_faq.txt new file mode 100644 index 00000000..a94a28f4 --- /dev/null +++ b/hurd/faq/old_hurd_faq.txt @@ -0,0 +1,289 @@ +The Unofficial (and no longer maintained) GNU Hurd FAQ, Version 0.13 + +Contributions by: + +Michael I. Bushnell <mib@gnu.org> +Len Tower <tower@gnu.org> +Trent Fisher <trent@gnurd.uu.pdx.edu> +jlr@usoft.spb.su +Remy Card <Remy.Card@masi.ibp.fr> +Louis-Dominique Dubeau <hallu@info.polymtl.ca> + +Original Document by: Derek Upham <upham@cs.ubc.ca> + + +============================== + +Contents: + +Q0. Where can I get the Unofficial GNU Hurd FAQ? +Q2. Where can I get a copy? +Q3. Why bother writing a new OS when we have Linux and 386/BSD? +Q4. What's all this about Mach 3.0 (and Mach 4.0)? +Q5. Where can I find more information? +Q6. What's a proper machine? +Q7. What sort of machines will run Hurd in the future? +Q8. What is the current development status? +Q9. What sort of system would we have if the Hurd was bootable today? + +============================== + +Q0. Where can I get the Unofficial GNU Hurd FAQ? + +The Unofficial Hurd FAQ (what you are reading now) is occasionally +posted to the USENET newsgroup, gnu.misc.discuss. It is also +available from + + http://www.enci.ucalgary.ca/~gord/hurd/hurd-faq.txt + +If you don't have WWW access, you may send mail to me, Gordon +Matzigkeit <gord@enci.ucalgary.ca> with a subject line that reads: + + Subject: send hurd-faq + +You should receive a PGP-signed copy of the current version of this +document in a matter of minutes. + + +Q2. Where can I get a copy? + +To put it simply, you can't. It is still under development (by +Michael Bushnell, Roland McGrath and Miles Bader). It is almost, but +not quite, at the point where you can do real work on it. Keep your +fingers crossed. + +Some people have actually bootstrapped it, but the work is not easy, +and the current snapshot won't work until a new multiserver boot +mechanism is made. + +If you *really* want to try it, beware that it is still pre-alpha +code, and that it will likely crash on you. See Trent Fisher's Hurd +pages (under question 5) for the latest information. + + +Q3. Why bother writing a new OS when we have Linux and 386/BSD? + +For one thing, Linux and BSD don't scale well. Hardware designers are +shifting more and more toward multiprocessor machines for performance, +and standard Unix kernels do not provide much multiprocessor support. +The Hurd, on the other hand, runs on top of the Mach 3.0 micro-kernel +[[1]] from CMU. Mach was designed precisely for multiprocessing +machines, so its portability should carry over nicely to the Hurd. + +In addition, the Hurd will be considerably more flexible and robust +than generic Unix. Wherever possible, Unix kernel features have been +moved into unprivileged space. Once there, anyone who desires can +develop custom replacements for them. Users will be able to write and +use their own file systems, their own `exec' servers, or their own +network protocols if they like, all without disturbing other users. + +The Linux kernel has now been modified to allow user-level file +systems, so there is proof that people will actually use features such +as these. It will be much easier to do under the Hurd, however, +because the Hurd is almost entirely run in user space and because the +various servers are designed for this sort of modification. + + +Q4. What's all this about Mach 3.0 (and Mach 4.0)? + +As mentioned above, Mach is a micro-kernel, written at Carnegie Mellon +University. A more descriptive term might be a greatest-common-factor +kernel, since it provides facilities common to all ``real'' operating +systems, such as memory management, interprocess communication, +processes, and a bunch of other stuff. Unfortunately, the system +calls used to access these facilities are only vaguely related to the +familiar and cherished Unix system calls. There are no "fork", +"wait", or "sleep" system-calls, no SIGHUPs, nothing like that. All +this makes it rather difficult to, say, port GNU Emacs to a Mach box. + +The trick is, of course, to write an emulation library. Unix programs +can then use (what they think are) POSIX system calls and facilities +while they are really using Mach system calls and facilities. + +The simplest way of going about this is to take an ordinary Unix +kernel, open it up, and rip out all the machine-specific guts; any +time the Unix kernel talks to the machine, replace the code with calls +to the Mach micro-kernel. Run this fake kernel on a Mach machine and +you end up with something that looks and acts just like Unix (even to +GNU Emacs). Note that the Unix kernel we have implemented is just one +Really Big Mach program (called a single-server). + +The Hurd, on the other hand, breaks the giant Unix kernel down into +various Mach programs running as daemons. Working in concert with +facilities placed in the C library, these daemons provide all of the +POSIX system-calls and features; from the outside they look just like +a standard Unix kernel. This means that, for practical purposes, +anything that you can port to Linux will also port to the Hurd. + +Of course, if a user wishes to run his own daemons, he can do that as +well.... + +Mach 4.0 is an enhanced version of Mach 3.0, put out by the people at +the University of Utah. They are working on another free operating +system, and part of it includes an enhanced, more flexible version of +Mach. The Hurd has moved to Mach 4.0, which is good, because it is a +lot easier to build than 3.0 was. + +You can find more information on Mach by browsing the Hurd pages given +in the next answer, or by looking at the Project Mach and Flux +homepages at: + +Carnegie Mellon University (for Mach versions before 4.0): + + http://www.cs.cmu.edu/afs/cs.cmu.edu/project/mach/public/www/mach.html + +the University of Utah (for Mach 4.0): + + http://www.cs.utah.edu/projects/flux/mach4/html/ + + +Q5. Where can I find more information? + +The June 1995 GNU's Bulletin contains the following official +information: + + The GNU Hurd now runs programs native. We have implemented both + shared libraries using ELF, & the popular `ext2' file system used + by Linux. It can run GCC, `make', Emacs, & most other GNU + utilities. Progress is being made so rapidly that by the time you + read this it probably does much more. It is right on the verge of + being self-hosting (able to run on its own well enough to compile + its own source code, & be used for its own development). We have + much better device supportm [sic] & some new utilities, including a + fancy `ps' & `settrans'. For a complete system we still have much + more work to do, but we will make an alpha release as soon as the + network software is finished & shared libraries have been well + tested. We have a mailing list to announce progress; to be added + to it, ask `hurd-announce-request@gnu.org'. + +The Portland State University CS department (via Trent Fisher) +maintains a WWW server with various Hurd documents, including Michael +Bushnell's Hurd paper, all the collected GNU's Bulletins, and various +announcements posted to "gnu.misc.discuss". The top-level GNU page is + + http://www.cs.pdx.edu/~trent/gnu/gnu.html + +and the Hurd page is + + http://www.cs.pdx.edu/~trent/gnu/hurd/hurd.html + +People in Europe might want to try the GNU WWW server for DESY +Germany, first: + + http://info.desy.de/gnu/www + +This site lacks culled, Hurd-specific information at the moment, but +it does have the last two GNU's Bulletins plus lots of general +information. + +There is a snapshot of the Hurd development tree on +"alpha.gnu.ai.mit.edu" in the "/gnu" directory. It is updated as +significant changes are made, and not guaranteed to run. + +You can subscribe to the Hurd announcement list by sending a request +to "hurd-announce-request@gnu.org". This is a moderated list +for distributing Hurd info to ``all and sundry'', and anyone can join. +In addition, there is a private (invitation-only) list for developers +to coordinate their efforts. It's not even worth thinking about +unless you (a) have a lot of free time on your hands, (b) know Unix +internals and Mach very well, and (c) have a proper machine. + + +Q6. What's a proper machine? + +A ``proper machine'', at the moment, means an x86 box running Mach 3.0 +(or 4.0), with FreeBSD 2.x, NetBSD 1.x, or Linux. + +A single-server OS is no longer required for development because by +the time the Hurd bootstrap mechanism is finished, the Hurd will +probably be self-hosting. + +Linux, FreeBSD, or NetBSD will only be required to splat the Hurd +binaries onto a partition of some sort, and to provide a way of +transferring files to the Hurd until the networking code is ready. + + +Q7. What sort of machines will run Hurd in the future? + +The first thing a prospective Hurd machine needs is a Mach 3.0 port. +According to the most recent "comp.os.mach" FAQ (which hasn't been +updated since February 1994), the following chips have redistributable +Mach micro-kernels and device drivers: + + Intel 80x86 (ISA and PS/2 buses) + Motorola 68000 (Sun 3) + Motorola 88000 (Omron Luna) + DEC Vax + DEC Pmax (DECstation 3100) + DEC Alpha + MIPS R4000 (DECstation 5000 et al.) + IBM RS/6000 + Apple Macintosh + +IBM is planning to run WorkplaceOS (the OS/2 successor) over Mach 3.0 +on the PowerPC chip (closely related to the RS/6000), so the PowerPC +will likely be added to this list soon. The University of Utah has +ported Mach 4.0 to the HP700, but it is not yet stable. + +Sun Sparc machines have a redistributable Mach microkernel, but the +device drivers require a SunOS 4.1.1 source license. + +In addition, any prospective Hurd machine needs a port of the GNU C +library. Version 1.07.4 of the library can handle the following +chips: + + Intel 80x86 (BSD, Dynix, Hurd, SCO, SysV) + Motorola 68000 (HP BSD, NEWS, Sun 4) + MIPS R4000 (Ultrix) + Sun Sparc (Solaris 2, Sun 4) + DEC Alpha (OSF/1, mostly finished) + +So if the next Hurd snapshot is self-hosting, we will be able to run +it (in theory) on Intel 80x86s, Motorola 68000s, MIPS R4000s and DEC +Alphas. + +People who can port the Mach micro-kernel to new architectures are +encouraged to do so. People who can port the GNU C library to new +chips (a much larger group) are also encouraged to do so. You can +help out here without knowing anything about Mach or having any +special machine. Note that once the GNU C library exists for a new +chip, for _any_ OS, making a Hurd port later is simple (and making +ports to other chips becomes easier as well---the effects are +cumulative). + +By current indications, the other hardware requirements (RAM, disk +space, and the like) will be about the same as those of BSD 4.4. + + +Q8. What is the current development status? + +Please see Trent Fisher's Hurd pages for details. + + +Q9. What sort of a system would we have if the Hurd was bootable +today? + +Quite likely, if you already use an end-user system like Linux, +FreeBSD, or NetBSD, you'll be disappointed with the Hurd. It will +take some time before the OS hackers really get to work on +applications and major enhancements. + +But, rest assured, Hurd development should proceed very rapidly. + +Of course, if you think you can help, or you just enjoy neat stuff, +then you'll probably like the Hurd. When you actually understand a +fraction of what's going on behind the scenes, it's very impressive. + +All I'm saying is that I'm not expecting all the Windows '95 users in +the world to switch to the Hurd right away. Wait a little while, +maybe 5-6 years (ample time for GNUStep and Guile to be in use), and +GNU users everywhere will be very happy that the FSF proceeded with +the Hurd. :) + + +============================== + +Footnotes: + +[[1]] Yes, I know that ``micro-kernel'' is about as apt a description +as ``Reduced Instruction Set Chip'', but we're stuck with it. diff --git a/hurd/getting_help.mdwn b/hurd/getting_help.mdwn index 540dc851..c4f80ff9 100644 --- a/hurd/getting_help.mdwn +++ b/hurd/getting_help.mdwn @@ -11,16 +11,11 @@ is included in the section entitled # Essential Documentation * [[FAQ]] -* [[microkernel/mach/gnumach/Hardware_Compatibility_List]] +* [[microkernel/mach/gnu_mach/Hardware_Compatibility_List]] # Forums -Please follow these [guidelines](http://catb.org/~esr/faqs/smart-questions.html) -when asking your question. Namely: spend some time trying -to solve the problem on your own (e.g., [search the web](http://www.google.com), -use this wiki, etc.), show us that you did so when you -ask your question, and provide as many relevant details as possible -reproducing them as exactly as possible. +[[inline pages=asking_questions raw=yes feeds=no]] * [[Mailing_lists]] * [[IRC]] diff --git a/hurd/history.mdwn b/hurd/history.mdwn index 7ee5df5a..e749136f 100644 --- a/hurd/history.mdwn +++ b/hurd/history.mdwn @@ -1,4 +1,5 @@ -[[meta copyright="Copyright © 2007, 2008 Free Software Foundation, Inc."]] +[[meta copyright="Copyright © 1998, 1999, 2001, 2002, 2007, 2008 Free Software +Foundation, Inc."]] [[meta license="""[[toggle id="license" text="GFDL 1.2+"]][[toggleable id="license" text="Permission is granted to copy, distribute and/or modify this @@ -8,5 +9,79 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] -<a href="http://lists.gnu.org/archive/html/l4-hurd/2005-10/msg00718.html" target="_top">History 1997-2003</a></dt> -<dd> Personal view of Marcus Brinkmann about Hurd development in 1997-2003. +Richard Stallman (RMS) started GNU in 1983, as a project to create a +complete free operating system. In the text of the GNU Manifesto, he +mentioned that there is a primitive kernel. In the first GNUsletter, +Feb. 1986, he says that GNU's kernel is TRIX, which was developed at +the Massachusetts Institute of Technology. + +By December of 1986, the Free Software Foundation (FSF) had "started +working on the changes needed to TRIX" [Gnusletter, Jan. 1987]. +Shortly thereafter, the FSF began "negotiating with Professor Rashid +of Carnegie-Mellon University about working with them on the +development of the Mach kernel" [Gnusletter, June, 1987]. The text +implies that the FSF wanted to use someone else's work, rather than +have to fix TRIX. + +In [Gnusletter, Feb. 1988], RMS was talking about taking Mach and +putting the Berkeley Sprite filesystem on top of it, "after the parts +of Berkeley Unix... have been replaced." + +Six months later, the FSF is saying that "if we can't get Mach, we'll +use TRIX or Berkeley's Sprite." Here, they present Sprite as a +full-kernel option, rather than just a filesystem. + +In January, 1990, they say "we aren't doing any kernel work. It does +not make sense for us to start a kernel project now, when we still +hope to use Mach" [Gnusletter, Jan. 1990]. Nothing significant occurs +until 1991, when a more detailed plan is announced: + +<BLOCKQUOTE> +We are still interested in a multi-process kernel running on top of +Mach. The CMU lawyers are currently deciding if they can release Mach +with distribution conditions that will enable us to distribute it. If +they decide to do so, then we will probably start work. CMU has +available under the same terms as Mach a single-server partial Unix +emulator named Poe; it is rather slow and provides minimal +functionality. We would probably begin by extending Poe to provide +full functionality. Later we hope to have a modular emulator divided +into multiple processes. [Gnusletter, Jan. 1991]. +</BLOCKQUOTE> + +RMS explains the relationship between the [[documentation/Hurd_and_Linux]], where he mentions +that the FSF started developing the Hurd in 1990. As of [Gnusletter, +Nov. 1991], the Hurd (running on Mach) is GNU's official kernel. + +--- + +# Announcements + +These are all the announcements made over the years. Most of them were +either sent to the <A HREF="news:gnu.announce">gnu.announce</A> news group or Hurd interest +mailing lists. + + * [[hurd-flash15]] -- Release 0.2 announcement (complete GNU system) + * [[hurd-flash14]] -- Release 0.2 announcement (Hurd) + * [[hurd-flash13]] -- Test release announcement (Aug 96) + * [[hurd-flash12]] -- Test release status (Jul 96) + * [[hurd-flash11]] -- Binary image available, Apr 96 + This and [NetBSD](http://www.netbsd.org/) boot flopies should be enough to + get a working GNU/Hurd system! + * [[hurd-flash10]] -- New Snapshot, Apr 96 -- NFS and lots else works! + * [[hurd-flash9]] -- News Flash, Nov 95 -- ftp works! + * [[hurd-flash8]] -- New Snapshot, Jul 95 -- ext2fs support + * [[hurd-flash7]] -- New Snapshot, Apr 95 + * [[hurd-flash6]] -- News flash, Nov 94 + * [[hurd-flash5]] -- News flash, Sep 94 -- gcc runs! + * [[hurd-flash4]] -- News flash, Aug 94 + * [[hurd-flash3]] -- News flash, Jul 94 -- emacs runs! + * [[hurd-flash2]] -- News flash, May 94 + * [[hurd-flash]] -- News flash, Apr 94 -- it boots! + * [[hurd-announce2]] -- GNU Hurd announcement, Nov 93 + * [[hurd-announce]] -- GNU Hurd announcement, May 91 + +--- + + * [History + 1997-2003](http://lists.gnu.org/archive/html/l4-hurd/2005-10/msg00718.html) + -- personal view of Marcus Brinkmann about Hurd development in 1997-2003. diff --git a/hurd/history/hurd-announce b/hurd/history/hurd-announce new file mode 100644 index 00000000..2f165ad8 --- /dev/null +++ b/hurd/history/hurd-announce @@ -0,0 +1,47 @@ +From mib@PREP.AI.MIT.EDU Tue May 7 12:07:53 1991 +From: mib@PREP.AI.MIT.EDU +Newsgroups: gnu.announce +Subject: FSF work on a GNU OS +Date: 6 May 91 22:15:22 GMT +Reply-To: mib@prep.ai.mit.edu +Distribution: gnu +Organization: GNUs Not Usenet + +The Free Software Foundation is beginning work on a GNU operating +system built on top of the Mach 3.0 microkernel. There are three +goals to this project worth noting: + +o Binary compatability with 4.4 BSD, and other U*x or U*xish systems + on other hardware where appropriate, convenient, and consistent with + the design; + +o Posix compliance (in combination with the GNU C Library and the GNU + C Compiler); and + +o Ease of use as well as several new features and functionality. + + +I am interested in constructive criticism on the interfaces, design, +and implementation from experts in the field of OS research and design +consistent with the above goals. Advice from seasoned U*x hackers is +especially welcome. + +We have a mailing list for discussion. Currently there is little +discussion on the group; the major contributors to the ideas behind +the design all live in the Boston area at this point, and work has +been done via face-to-face communication. I would like to open the +field of discussion to a broader base, both to get wider dissemination +of the ideas behind the current design, as well as to get a greater +breadth of criticism. Periodic postings are currently made to the +mailing list containing a snapshot of the interfaces used by the +various pieces of the system. I would like to see discussion as well; +perhaps we need a critical mass to get this. + +Interested individuals should send me email. I don't regularly read +the newsgroups to which this message is posted. + + +[U*x is an abbreviation for a well-known trademark of AT&T. :-)] + + -mib + diff --git a/hurd/history/hurd-announce2 b/hurd/history/hurd-announce2 new file mode 100644 index 00000000..dce41c43 --- /dev/null +++ b/hurd/history/hurd-announce2 @@ -0,0 +1,143 @@ +From mib@gnu.ai.mit.edu Wed Nov 3 21:51:03 1993 +Path: usenet.ee.pdx.edu!cs.uoregon.edu!ogicse!emory!nigel.msen.com!sdd.hp.com!swrinde!cs.utexas.edu!uunet!spool.mu.edu!bloom-beacon.mit.edu!ai-lab!prep.ai.mit.edu!gnulists +From: mib@gnu.ai.mit.edu (Michael I Bushnell) +Newsgroups: gnu.announce,gnu.misc.discuss +Subject: Hurd status and call for volunteers +Message-ID: <9311020719.AA02206@geech.gnu.ai.mit.edu> +Date: 1 Nov 93 21:19:05 GMT +Article-I.D.: geech.9311020719.AA02206 +Followup-To: gnu.misc.discuss +Distribution: world +Lines: 124 +Approved: info-gnu@prep.ai.mit.edu +To: info-gnu@prep.ai.mit.edu +X-Shopping-List: + (1) Chaotic casino griddles (2) Cervical congestion (3) Neoclassical + consoles +Xref: usenet.ee.pdx.edu gnu.announce:160 gnu.misc.discuss:3985 + +This message to help sate curiosity, as well as to ask for volunteers. +Until we are ready for alpha test, this is the last such message that +will be posted here. If you want to receive further such messages, +send mail to hurd-ann-request@gnu.ai.mit.edu and ask to be put on that +(moderated) announcements list. + + +What is already done with the Hurd: + +The filesystem is complete; it runs (read-only), and most of its calls +have been tested and work. The filesystem is able to download +programs, by a kludge similar to the kludge used to enable the kernel +to download the first task. In the actual bootstap sequence, it will +download the execserver. + +The proc and auth servers are completed; the exec server is nearly +complete (for a.out, not for bfd). + +C library support for Mach and Hurd rpc stubs, and some of the mach +and hurd specific code, is done. Much untested and probably wrong +code has been written to implement Unix "system calls". A large piece +of this (the descriptor management code) is believed by Roland to have +some architectural flaw, but he isn't sure. + +Some small filesystem servers (shadow directories, for example) have +been written, but have not been compiled, let alone tested. + + +There are currently three things happening wrt the Hurd: + +I am spending nearly all my time getting things to boot and run. My +work is currently directed toward that goal; in the immediate present +I am working with Roland on getting the library in its near-final +state (which will last a long time) to make compiling easier. It is +because this is nearly done that I can send this message. + +Roland is working on the library. Most of the remaining architectural +work is done and being tested. Then Roland will work on integrating +cthreads (which is mostly busywork), miscellaneous filesystem calls, +and then file descriptors. After that comes signals. + +Jan Brittenson will be working on the network server library. This is +a library that, when linked against a BSD protocol stack, will produce +a Hurd network server. (Such a server implements the socket interface +in socket.defs.) + + +There are four general tasks that can be done by other people: + +1. Completing the existing work on the terminal driver. The existing +work implements most of the logic you already associate with a Posixy +terminal driver; it needs the port management and buffering logic +added. + +2. Writing a readline terminal driver. We will want, as an +alternative to the Posixy terminal driver, a readline type terminal +driver. + +3. Writing miscellaneous shell utilities. Here we need shell +utilities to create translators, etc. They should have a nice rich +set of features to do all kinds of GNU things. + +4. Writing miscellaneous filesystem servers. Here we need a +transparent tar server, a transparent FTP server, and the like. + + +Future plans for work to be written by me (once the bootstrap works, +and in addition to testing library code as Roland finishes it): + +o split the existing filesystem into three parts: + o a library for port management for complicated multi-threaded + servers; + o a library for "normal" disk-based filesystems; + o ufs specific code. + +o Write the PF_FILE socket server (what you know as PF_UNIX). + +o Finish the posixy terminal driver if nobody else has. + +o Write miscellaneous shell utilities that nobody else has. + +o Build a self-hosting system. + + +What you need in order to be able to help now: + +o A 386 PC running Mach 3.0. If you have some other kind of hardware, + then you need to port the GNU C library support first. I'm not + entirely sure how much work that involves; you will need to contact + Roland. It might be too much trouble at this point to spend any + effort on it. It's best if it's a machine for which a free port of + Mach is available, though you could do useful work even if it's not. + + If you are not currently running Mach 3.0 with somebody's + single-server, then it is very unlikely you could help, unless you + have a Unix source license. In that case, you could talk to CMU + (write mach@cs.cmu.edu) to find out how to get Mach 3.0 running on + your machine. It is not possible to do development without a Unix + emulator of some kind; just bare Mach 3.0 is not sufficient. I have + neither the time nor knowledge to help someone get a 3.0 + single-server system running. + +o Clue. I don't have enough time to explain operating systems or Unix + to people. You need to have an iron-clad grasp of Unix semantics + (specificaly BSD); it's essential that things be exactly right from + that standpoint. It's not enough that you've programmed Unix + before; you need to understand all the nits. However, you may + disregard my previous comments about a "two question limit". You do + need the ability to intuit to some extent, however. + +o Time. It's not good for me to delegate a task and then have nothing + happen on it. If you have a full-time job where you can't justify + Hurd work as part of your job, you might find that you don't really + have as much time as you thought. Please make sure you really have + enough time before volunteering for a task. + +o Efficient net access. Without a real Internet connection (mail only + is not sufficient), it will be impossible for you to do development + right now. + + +If you think you can help, send me email. If you don't think you can +help right now, then don't give up: the list of conditions will change +as the list of delegatable tasks changes. + diff --git a/hurd/history/hurd-flash b/hurd/history/hurd-flash new file mode 100644 index 00000000..d1bacc79 --- /dev/null +++ b/hurd/history/hurd-flash @@ -0,0 +1,22 @@ +Path: gnurd!usenet.ee.pdx.edu!cs.uoregon.edu!sgiblab!swrinde!gatech!europa.eng.gtefsd.com!MathWorks.Com!news.kei.com!bloom-beacon.mit.edu!ai-lab!life.ai.mit.edu!mib +From: mib@churchy.gnu.ai.mit.edu (Michael I Bushnell) +Newsgroups: gnu.misc.discuss,comp.os.mach +Subject: Hurd now bootstraps +Date: 05 Apr 1994 21:49:50 GMT +Organization: Free Software Foundation, Cambridge, MA +Lines: 11 +Message-ID: <MIB.94Apr5174952@churchy.gnu.ai.mit.edu> +NNTP-Posting-Host: churchy.gnu.ai.mit.edu + + +The GNU Hurd now bootstraps, successfully starting the core servers +(the filesystem, exec server, process server, auth server, and init) +and running the first program. A snapshot of the code that did this +is on alpha.gnu.ai.mit.edu in the usual place, /gnu/hurd-snap.tar.gz. + +-- ++1 617 623 3248 (H) | The soul of Jonathan was bound to the soul of David, ++1 617 253 8568 (W) -+- and Jonathan loved him as his own soul. +1105 Broadway | Then Jonathan made a covenant with David +Somerville, MA 02144 | because he loved him as his own soul. + diff --git a/hurd/history/hurd-flash10 b/hurd/history/hurd-flash10 new file mode 100644 index 00000000..d6d5685b --- /dev/null +++ b/hurd/history/hurd-flash10 @@ -0,0 +1,25 @@ +Date: Mon, 15 Apr 1996 15:28:29 -0400 +Message-Id: <199604151928.PAA00636@geech.gnu.ai.mit.edu> +From: mib@gnu.ai.mit.edu (Michael I. Bushnell, p/BSG) +To: hurd-ann@gnu.ai.mit.edu +Subject: New Hurd snapshot available +X-Geek-Code: (V2.1) GCS/J/M/MU/P/S/O>AT d- H-- s-: g+++ p0 !au a- w++ v+++(*) C+ ++$ UB++++$ P--- L 3- E++ N++ K++++ W-- M- V-- po-- Y+(--) t++ 5+ j++ R- G'''' tv ++ b+++ !D B-- e+ u++(*) h* f? r n y++ +X-Tom-Swiftie: "Use the `&' operator to get the address," Tom pointed out. +Sender: owner-abshurd@cs.pdx.edu +Precedence: bulk + + +I have just cut a new source snapshot. If things go nicely, a binary +snapshot may appear soon as well. You can find this snapshot as + +ftp://alpha.gnu.ai.mit.edu/gnu/hurd-snap-960415.tar.gz + +Many many things work! Emacs built native and just *went*. The +system now works standalone; you can use gdb (it's much nicer than +other mach-ish gdb's, of course); the network is functional (complete +with NFS), etc. + +Michael + diff --git a/hurd/history/hurd-flash11 b/hurd/history/hurd-flash11 new file mode 100644 index 00000000..57851b01 --- /dev/null +++ b/hurd/history/hurd-flash11 @@ -0,0 +1,25 @@ +From: Miles Bader <miles@gnu.ai.mit.edu> +To: hurd-ann@gnu.ai.mit.edu +Date: Thu, 18 Apr 1996 19:08:07 -0400 +Subject: hurd binary image + + +A filesystem image from a working hurd system, corresponding to the latest +snapshot, is available as: + + ftp://alpha.gnu.ai.mit.edu/gnu/hurd-image-960418.tar.gz + +The whole tree takes about 37meg (warning -- it unpacks into `.'). Follow +the instructions in ./INSTALL-binary to make a working hurd system. + +Due to a timely trashing of the disk on our main hurd machine, it has been +verified that it is possible to make a bootable hurd system from scratch +using this image and a set of netbsd 1.1 boot floppies... + +The sources for the mach kernel included in the image are available in the +same directory as mach4-UK22.tar.gz and mach4-i386-UK22.tar.gz. + +-Miles +-- +Miles Bader / miles@gnu.ai.mit.edu / (617) 253-8568 +Amadera e ike! diff --git a/hurd/history/hurd-flash12 b/hurd/history/hurd-flash12 new file mode 100644 index 00000000..5be9c94e --- /dev/null +++ b/hurd/history/hurd-flash12 @@ -0,0 +1,76 @@ +From: mib@gnu.ai.mit.edu (Michael I. Bushnell, p/BSG) +Newsgroups: gnu.misc.discuss +Subject: Hurd 0.0 release status +Followup-To: gnu.misc.discuss +Date: 13 Jul 1996 23:53:41 GMT +Organization: Touring Consulting Services +Lines: 35 +Message-ID: <MIB.96Jul13195341@gnu.ai.mit.edu> +NNTP-Posting-Host: churchy.gnu.ai.mit.edu + + +People are eager to know how close we are to release, so here's an +update: + +There is one rather annoying bug I'd like to find which is causing +random crashes. I expect this will not be too hard to locate. There +are some more trivial bugs, but the release will not be held up for +them. + +Forty-three packages of GNU software have been built native. +Remaining to be built are three packages for which new releases are +expected soon. + +Also remaining to be built native are bash, gdb, mach, the Hurd +itself, and the internet utilities and daemons. We intend to sync our +separate copy of libc source with the libc maintainer, and then build +it native too. + +Because of obnoxious export restrictions, we have still to make +separate shared libraries for the crypt functions. + +Except for the actual final packaging, all the release engineering +tasks to be done have been completed. + + +To summarize, we still need to: + +o Fix one obnoxious bug +o Compile three packages that are waiting for release; +o Compile gdb, bash, mach, and hurd native +o Sync libc source and compile native +o Deal with crypt shared libraries +o Final packaging + +Michael + +From: mib@gnu.ai.mit.edu (Michael I. Bushnell, p/BSG) +Newsgroups: gnu.misc.discuss +Subject: Re: Hurd--ne plus ultra of vaporware? +Date: 17 Jul 1996 03:02:14 GMT + +In article <4sg6tp$n4t@linux.cs.Helsinki.FI> torvalds@linux.cs.Helsinki.FI (Linus Torvalds) writes: + + Hey! We could also ask some well-known rock-group for one of their + lyrics, and use that as the theme song for the Hurd release. And then + we could ask shops to stay open longer to sell the Hurd! Whaddaya think? + Don't say it has been delayed, just shout so loudly about all the new + features that nobody cares about the delay? + +Perhaps we could get Morrisey to sing the song. He's very good +looking. Much better looking than that Mick Jagger fellow. + +Or something delicate, like Bach's French Suite in G. That would be +fun. + +In any case, here's the state of the release: + +o Everything but nine packages has been compiled native. +o The random crash bug I alluded to is fixed. +o We have to build a floppy image for part of the installation instructions. + +That's it. I bet you nobody in Redmond has ever made a statement like +that... + +Michael + diff --git a/hurd/history/hurd-flash13 b/hurd/history/hurd-flash13 new file mode 100644 index 00000000..a2de6bfd --- /dev/null +++ b/hurd/history/hurd-flash13 @@ -0,0 +1,120 @@ +Date: Mon, 5 Aug 1996 22:36:31 -0400 +From: thomas@gnu.ai.mit.edu (Thomas Bushnell, n/BSG) +To: info-gnu@prep.ai.mit.edu, hurd-ann@gnu.ai.mit.edu, hurd-dev@gnu.ai.mit.edu +Subject: Hurd 0.0 and GNU 0.0 released +X-Name-Change: My name used to be `Michael'; now it is `Thomas'. +X-Tom-Swiftie: "I guess I shouldn't have broken the mirror," Tom reflected. + + + + +I am pleased to announce version 0.0 of the GNU Hurd, available via +anonymous FTP from prep.ai.mit.edu [18.159.0.42] in the file +/pub/gnu/hurd-0.0.tar.gz (about 1.2 MB compressed). + +This file contains complete source code for the following: + +Hurd servers: + + auth, crash, devio, devport, exec, ext2fs, fifo, fwd, ifsock, init, + magic, new-fifo, nfs, null, pfinet, pflocal, proc, symlink, term, + ufs. + +Hurd libraries: + + diskfs, fshelp, ihash, iohelp, netfs, pager, pipe, ports, ps, + shouldbeinlibc, store, threads, trivfs. + +Hurd utilities and other programs: + + boot, shd, ps, settrans, showtrans, sync, su, mount, fsysopts, + storeinfo, login, w, uptime, hurdids, loginpr, sush, vmstat, + portinfo, devprobe, reboot, halt, fsck, fsck.ufs, mkfs.ufs, clri.ufs, + stati.ufs, getty, rc. + + +------ + + +In addition, we have prepared a binary distribution of a complete +version 0.0 GNU system corresponding to this Hurd release. This +release runs only on PC-AT compatible systems with i[345]86 +processors. + +The GNU Hurd, plus Mach, is a kernel, not an operating system. The +GNU operating system, like the Unix operating system, consists of many +components, including kernel, libraries, compilers, assembler, shell, +parser generators, utilities, window system, editors, text formatters, +and so on. The GNU project set out a decade ago to develop this +system, and we've been writing various components of it ever since. + +This release uses the `UK22' version of the Mach kernel, as +distributed by the University of Utah. It is too difficult to prepare +a detailed list of supported devices at this point. Common disk +controllers and ethernet cards are generally supported. + +This release does not contain the X Window System. + +This release may be fetched by anonymous FTP from prep.ai.mit.edu +[18.159.42] in the directory /pub/gnu/gnu-0.0/. + +In that directory, you should find the following files: + + README + SOURCES + INSTALL-binary + grub-boot.image (about 1.4 MB, not compressed) + gnu-0.0.tar.gz (about 56.9 MB compressed) + gnu-0.0-stripped.tar.gz (about 26.2 MB compressed) + +SOURCES contains a complete list describing the sources for the +binaries found in the image. INSTALL-binary contains complete +installation instructions for this release. + +(The files README, SOURCES, and INSTALL-binary are also found in the +root directory of the gnu-0.0 release.) + +gnu-0.0.tar.gz holds the image of the complete system. It unpacks +into a directory that requires approximately 233 MB of disk space. + +gnu-0.0-stripped.tar.gz holds the same contents as gnu-0.0, except +that executable programs have been stripped to save space, and the +libraries have had debugging symbols stripped to save space and speed +linking. It unpacks into a directory that requires about 85.5 MB of +disk space. + +We recommend using the unstripped image, or you will be unable to +debug anything. Surely there are bugs. So fetch the unstripped +image, at least to have around. + +grub-boot.image is an image of a 3.5" floppy disk that you will need +in order to complete part of the installation instructions. + +The following free software packages are found in this release: + + autoconf, automake, bash, bc, binutils, bison, cpio, cvs, diffutils, + doschk, e2fsprogs, ed, emacs, fileutils, findutils, flex, from, gawk, + gcal, gcc, gdb, gdbm, gettext, glibc, gmp, gperf, grep, grub, gzip, + hello, hurd, indent, inetutils, less, mach, make, m4, miscfiles, + ncurses, nethack, nvi, patch, ptx, rcs, readline, recode, sed, + serverboot, sharutils, shellutils, tar, termcap, termutils, texinfo, + textutils, time, wdiff. + + +------ + + +Here are md5sum checksums for the files mentioned in this message: + +b5f888bab3eb193fe97a00a141324c9d INSTALL-binary +345dcd826747d7b11fc78f4db162d75b README +1a5744bb4ed3448045fa6d24153d65fe SOURCES +f7b1bc428bc4ee29977a5b28f5762092 gnu-0.0-stripped.tar.gz +24554c58e5c89f295176e17d21dbae8e gnu-0.0.tar.gz +8338c619d860b71bc4128c9c0fd39d63 grub-boot.image +1fd18ccc4c81d051b83d28b13dc07ee2 hurd-0.0.tar.gz + +----- + +Br. Thomas Bushnell, n/BSG + diff --git a/hurd/history/hurd-flash14 b/hurd/history/hurd-flash14 new file mode 100644 index 00000000..2d67687a --- /dev/null +++ b/hurd/history/hurd-flash14 @@ -0,0 +1,62 @@ +I am pleased to announce version 0.2 of the GNU Hurd, available via +anonymous FTP from prep.ai.mit.edu [18.159.0.42] in the file +/pub/gnu/hurd-0.2.tar.gz (about 1.37 MB compressed). + +(The GNU Hurd, plus Mach, is a kernel, not an operating system. The +GNU operating system, like the Unix operating system, consists of many +components, including kernel, libraries, compilers, assembler, shell, +parser generators, utilities, window system, editors, text formatters, +and so on. The GNU project set out a decade ago to develop this +system, and we've been writing various components of it ever since.) + +This release contains many bug fixes from version 0.1. Many thanks to +all the people who are helping find bugs! + +The best way you can help find bugs is to try and compile and use on +the Hurd as many programs as you can find and find out where bugs +still exist. There are also unimplemented features, and your reports +will help us to prioritize which things we work on. + +The system is vastly more reliable than it has been in the past. + +One important addition: + + New programs addauth, rmauth, unsu, su, and setauth modify the uid + sets of running programs. Using addauth you can add root to your + emacs, write a file, and then use rmauth to take the uid back. (Of + course, passwords are required when necessary.) New program `ids' + will tell you what all the user ids are that a program has. Note + that in the Hurd a program can have several user ids all at once, + just like Unix supports having several group ids. Now that you can + dynamically change the ids of running programs, system + administration (among other things) becomes much easier. + +For more detailed news, see the NEWS file in the distribution. + +This release contains complete source code for the following: + +Hurd servers: + + auth, crash, devport, exec, ext2fs, fifo, fwd, ifsock, init, + magic, new-fifo, nfs, null, pfinet, pflocal, proc, symlink, term, + ufs, storeio, firmlink. + +Hurd libraries: + + diskfs, fshelp, ihash, iohelp, netfs, pager, pipe, ports, ps, + shouldbeinlibc, store, threads, trivfs, hurdbugaddr, ftpconn + +Hurd utilities and other programs: + + boot, shd, ps, settrans, showtrans, sync, su, mount, fsysopts, + storeinfo, login, w, uptime, ids, sush, vmstat, portinfo, devprobe, + reboot, halt, fsck, fsck.ufs, mkfs.ufs, clri.ufs, stati.ufs, getty, + rc, e2os, vminfo, nfsd, mail.local, serverboot, MAKEDEV, loginpr, + addauth, rmauth, unsu, setauth, ftpcp, ftpdir. + +We are also making a complete GNU 0.2 binary release, which will +include Hurd 0.2, glibc 2.0.4, gnumach 1.1.2, and many other +programs. This binary release is announced separately. + + +Thomas Bushnell, n/BSG diff --git a/hurd/history/hurd-flash15 b/hurd/history/hurd-flash15 new file mode 100644 index 00000000..0785ac59 --- /dev/null +++ b/hurd/history/hurd-flash15 @@ -0,0 +1,60 @@ + +I am pleased to announce version 0.2 of the complete Hurd based GNU +system. This release runs only on PC-AT compatible systems with +i[3456]86 processors. + +The GNU Hurd, plus Mach, is a kernel, not an operating system. The +GNU operating system, like the Unix operating system, consists of many +components, including kernel, libraries, compilers, assembler, shell, +parser generators, utilities, window system, editors, text formatters, +and so on. The GNU project set out a decade ago to develop this +system, and we've been writing various components of it ever since. + +This release uses the GNUmach distribution of the Mach kernel, version +1.1.3. Popular PC devices are generally supported. + +This release does not contain the X Window System. + +This release may be fetched from the directory +ftp://prep.ai.mit.edu/pub/gnu/gnu-0.2. (prep.ai.mit.edu is 18.159.42, +for the nameserver-impaired). + +In that directory, you should find the following files: + +README +SOURCES +INSTALL-binary +grub-boot.image (about 1.5 MB, not compressed) +gnu-0.2.tar.gz (about 73 MB compressed) + +SOURCES contains a complete list describing the sources for the +binaries found in the image. INSTALL-binary contains complete +installation instructions for this release. + +(The files README, SOURCES, and INSTALL-binary are also found in the +root directory of the gnu-0.2 release.) + +gnu-0.2.tar.gz holds the image of the complete system. It unpacks +into a directory that requires approximately 285 MB of disk space. + +grub-boot.image is an image of a 3.5" floppy disk that you will need +in order to complete part of the installation instructions. + +The following free software packages are included in this release: + +autoconf automake bash bc binutils bison cpio cvs diffutils doschk +e2fsprogs ed emacs emacs lisp manual fileutils findutils flex from g77 +gawk gcal gcc gdb gettext glibc gmp gnuchess gnumach gnugo grep grub +gzip hello hurd indent inetutils less libg++ lynx m4 make miscfiles +ncurses nethack nvi patch perl ptx readline rcs recode sed sendmail +sh-utils sharutils tar termutils texinfo textutils time wdiff + +-- + +Here are md5sum checksums for the files mentioned in this message: + +3749b016ab581e007b90d17b9092e134 INSTALL-binary +1f800c326ba4c3a0b3f3a3463597317b README +40d1e1a38dd86f28fe2718081ac865cb SOURCES +f29c1a03c1667a8019b66f6effa89d39 gnu-0.2.tar.gz +8ad3c7254802a16068a956e836266212 grub-boot.image diff --git a/hurd/history/hurd-flash2 b/hurd/history/hurd-flash2 new file mode 100644 index 00000000..b1d4f66f --- /dev/null +++ b/hurd/history/hurd-flash2 @@ -0,0 +1,152 @@ +From: mib@churchy.gnu.ai.mit.edu (Michael I Bushnell) +Newsgroups: gnu.misc.discuss,comp.os.mach,comp.os.linux.development,comp.os.linux.misc,comp.unix.pc-clone.32bit +Subject: GNU Hurd Task List and Call for Volunteers +Followup-To: gnu.misc.discuss +Date: 18 May 1994 17:54:47 GMT +Organization: FOO +Lines: 140 +Message-ID: <MIB.94May18135447@churchy.gnu.ai.mit.edu> +NNTP-Posting-Host: churchy.gnu.ai.mit.edu +Xref: usenet.ee.pdx.edu gnu.misc.discuss:7630 comp.os.mach:1434 comp.os.linux.d +evelopment:9867 comp.os.linux.misc:16767 comp.unix.pc-clone.32bit:5854 + + +Now that the Hurd can run (albeit haltingly) on its own, it is +possible for people who do not have Mach 3.0 single-servers to +contribute without much trouble. (However, if you don't have a +single-server, you probably won't be able to use a debugger, but that +doesn't mean you can't do debugging, right?) + +We at the FSF don't have any expertise in setting up Mach 3.0 +machines; the machines that we do development on belong to the Open +Software Foundation and were set up by them. So one of the things on +the task list is to organize things so that people (like us and most +of you) who don't know how to do it can do it. It's not impossible to +figure out, it's just a pain and a marvelous thing for a volunteer to +do. + +You can get Mach 3.0 from CMU; you get the C library and the Hurd from +us. You need the soon-to-be-released version 1.07.6 of the C library +and the latest Hurd snapshot (as well as our special version of MiG) +from alpha.gnu.ai.mit.edu. + +All our work is based upon i386. The Hurd (except for a few programs; +see the Hurd README file) is machine independent. The C library +should not be too much trouble to port. Ports and information about +porting difficulty for either of these are greatly desired. + +The Hurd is not yet self-hosting. While you are welcome to fetch the +code and put things together, it is not likely that you will have a +useful system right now. But you might be able to do significant work +(see the task list below). And, even if you can't do significant +work, I'm interested in hearing about any places where you had +particular difficulty. + +If you want to start on one of these tasks, please let me know so I +can keep track of volunteers properly. This task list will be updated +periodically; gnu@prep.ai.mit.edu always has the latest version. + + -mib + +GNU Hurd Task List Version 1.0. + +If you would like to work on one of these, please contact mib@gnu.ai.mit.edu. + + +Mach 3.0 Work + + o Mach 3.0 comes with CMU makefiles that depend on a drecky environment. + It would be very helpful to have makefiles and installation stuff so + that it worked well for cross-compilation between systems and used + GNU tools. + + o MiG needs to be made able to support cross-compilation. + + o A replacement for MiG that understood C .h files. + + o Bootstrap tools and documentation to help people set up Mach 3.0 + machines if they already have Linux; if they already have Net BSD; + if they don't have anything. + + o Mach 3.0 needs to provide support for task virtual timers similar + in functionality to the Unix ITIMER_PROF and ITIMER_VIRTUAL timers. + + o Mach 3.0 needs to provide a way for users to do statistical PC + profiling similar to the Unix profil system call. + + o Mach 3.0 needs a facility to automatically send task and thread + status on task/thread exit to a port that can only be changed by + a privileged user; this would be used to implement process + accounting. + + o Mach 3.0 needs a facility to find out what task is the parent of + a given task. + + o Mach 3.0 needs a facility to find out which pages of a task's + address space are in core to implement Unix's mincore call. + + o Mach 3.0 needs a facility to do msync. + + o Mach 3.0 needs a replacement for MEMORY_OBJECT_COPY_CALL that + works at least for the cases needed in ordinary files. (Write mib if + you want to know what the problem is and some ideas about how to + solve it.) + + o Mach 3.0 needs proxy memory objects. (mib can tell you what these + are and why they are important.) + + o Mach 3.0 needs a way to do per-task resource counters that are + accessible to servers called by the task. + + o Mach 3.0 needs facilities to implement resource limits of various sorts. + + o Mach 3.0 needs a way to have a thread's CPU time statistics + include time spent by servers on its behalf. + + o Of course, free ports are always necessary to machines that don't + already have free ports. + + o Much work can be done doing research in how to improve Mach VM + performance and timesharing scheduling policy. + + +Hurd work (these are brief descriptions; mib can give more information): + + o We need a translator for /dev. + + o We need a replacement for utmp and wtmp that understands the + Hurd `login collection' concept. Programs like who and finger + then need to be changed to use this. + + o We need some existing shell programs changed to do Hurd things: + like ls, su, fsck, tar, cpio, etc. + + o Some new programs need to be written: login, getty, ps, tools + for new filesystem features. + + o Shadow directory translators. (Roland has the beginnings of this.) + + o A system for write, send, talkd and so forth to bleep users; + this should be integrated with the utmp replacement above. + + o X. + + o A filesystem for /tmp that uses virtual memory instead of disk. + + o Filesystem implementations (using libdiskfs) for other popular + formats, especially the Linux formats as well as MSDOG. + + o Transparent FTP translator. + + o NFS client implementation. You should start with BSD's 4.4 code + and support the extensions they support; don't worry about Hurd + extensions right now. (The server we want to write ourselves + because it will probably involve changing the Hurd interfaces.) + + o A fancy terminal driver that uses readline and supports detach/attach. + +-- ++1 617 623 3248 (H) | The soul of Jonathan was bound to the soul of David, ++1 617 253 8568 (W) -+- and Jonathan loved him as his own soul. +1105 Broadway | Then Jonathan made a covenant with David +Somerville, MA 02144 | because he loved him as his own soul. diff --git a/hurd/history/hurd-flash3 b/hurd/history/hurd-flash3 new file mode 100644 index 00000000..19a5f371 --- /dev/null +++ b/hurd/history/hurd-flash3 @@ -0,0 +1,77 @@ +Date: Tue, 05 Jul 1994 20:15:09 -0400 +From: mib@gnu.ai.mit.edu (Michael I Bushnell) +To: hurd-ann@gnu.ai.mit.edu +Subject: New Hurd snapshot + + +A new Hurd snapshot has been released. You can get it from +alpha.gnu.ai.mit.edu in the file /gnu/hurd-snap.tar.gz. You will need +the most recent version of the GNU C library; version 1.08.3 or later. +(Version 1.08.3 is an alpha release; you can get it from +alpha.gnu.ai.mit.edu in the same directory.) + +This snapshot of the Hurd has a limping terminal driver. It can run +emacs, bash, a whole slew of utilities, and (most importantly) GNU +Hello. + + -mib + + +Here is the new part of the NEWS file: + +The Hurd now runs all the programs in the GNU fileutils, textutils, +and shellutils distributions, with the exception of who. Most +importantly it runs GNU Hello. Also, emacs works (with the kludgy +`boot' terminal driver) and bash works. + +The simple pipes server works; it will be replaced eventually by the +pflocal server (which isn't done yet). The terminal driver is limping +but working. It doesn't support terminal ioctls yet. A minor bug in +auth has been fixed. boot interprets more Hurd protocols; this was +done to get emacs functioning. Some more-or-less serious bugs in exec +were fixed; they were found by running emacs (a quite large executable +indeed). At bootstrap time, init starts pipes and term itself; +eventually these will be passive translators, but we don't want to +write the new disk format until we're self-hosting or fsck and UX will +get confused. The file proc/primes.c has been documented; thanks go +to Jim Blandy. Some bugs in proc dealing with pgrp and wait were +fixed; a nasty hash table bug was also fixed. The simple shell can do +pipes. Several serious bugs in ufs were fixed dealing with extension +of large files and writes of data not aligned on block boundaries. +The ufs pager was over-serialized; that's been fixed. Directory +lookups and modifications now use mapped I/O directly; this is an +important speed-up. The structure of the pager lockes has been +changed significantly. UFS now supports Mach copying mode +MEMORY_OBJECT_COPY_DELAY; this significantly improves process startup +time. + +Some minor changes have been made to several interfaces. The +interface for fs.defs:dir_readdir has been totally changed. There are +some new fs.defs interfaces: file_check_access, file_notice_changes, +dir_notice_changes. The fsys.defs:fsys_getroot interface was changed +to work correctly. process.defs:proc_setprocargs is renamed, and a +fetch function proc_get_arg_locations is added. The ifsock.defs +interface was simplified. + +Several bugs were fixed in libdiskfs. The new dir_readdir interface +requires new support from format-specific code. Some race conditions +have been fixed. dir-pathtrans.c now deals correctly with multiple +slashes in a row. A new concept called "light references" allows +pagers to remain active without preventing truncate-on-nolinks from +working right. New interfaces in fs.defs are implemented (except +file_notice_changes). Active translator usage has been fixed to work +correctly, but passive translators are still untested. libdiskfs now +thinks it supports S_IFSOCK nodes, but that's untested (of course) +because pflocal isn't done yet. + +The passive translator startup interface in libfshelp has been +radically simplified. The pager library now lets other code set and +changee the attributes on objects, synchronously if desired. An +init/terminate race condition was fixed. The ports library now +allows single-threaded users to work right (they didn't before). The +trivfs library works; see the ifsock server for a simple example of +its use. See term or pipes for more complex examples. + +There is a task list in the file `tasks'; let me know if you are +interested in working on one of these. + diff --git a/hurd/history/hurd-flash4 b/hurd/history/hurd-flash4 new file mode 100644 index 00000000..89ae9848 --- /dev/null +++ b/hurd/history/hurd-flash4 @@ -0,0 +1,101 @@ +From: mib@gnu.ai.mit.edu (Michael I Bushnell) +To: hurd-ann@gnu.ai.mit.edu +Date: Mon, 8 Aug 94 16:01:23 -0400 +Subject: New Hurd Snapshot +X-Shopping-List: + (1) Starboard sauce (2) Cinematic lesions (3) Two-way alphabetic + accordions + + +A new Hurd snapshot has been placed on alpha.gnu.ai.mit.edu in +/pub/gnu/hurd-snap.tar.gz. + +It is expected that the next snapshot after this one will have signals +basically working and thus be usable for a self-hosting system. In +addition, the next snapshot will probably have the current state of +our networking code (which has been proceeding, but has been absent +from the snapshots). + +Here is the NEWS about this current snapshot, however. Because some +big changes were made to the makefile and directory structure, things +might have gotten inadvertently ommitted from the snapshot. If this +happened, please let me know ASAP and I'll fix it and make a new +snapshot. + + -mib + + +August 8, 1994: + +Structural changes: + +Makefiles have been vastly improved and are simpler. The programs +`su', `ps', and `sh' have been moved from separate dirs into `utils'; +the programs `symlink' and `ifsock' have been moved into `trans'. + +Several changes were made to GCC use. You should definitely get GCC +version 2.6.0 now. Version 2.6.1 will have distributed the proper +`specs' file for the i386-gnu target, but it isn't quite ready yet, so +you still have to copy hurd/gcc-specs into +gcc-lib/i386-gnu/2.6.0/specs. + + +Interface changes: + +The tioctl.defs suite is complete now. + +INTR RPC's have been changed; individual RPC's are no longer marked +INTR. Rather, entire interfaces are marked `INTR_INTERFACE' if they +conform to the library's signalling/interruption expectations. + +There is a new magical retry type (for dir_pathtrans and fsys_getroot) +called `machtype' and a new one `/'; the former is for @sys tweaks and +the latter cleans up the retry of root-based symlinks a bit. + +There is a new interface `login.defs'. + +The "dotdot node" is no longer passed at fsys_startup time; instead, +it is passed by fsys_getroot. + + +Library changes: + +The ports library now does death-timeouts for multi-threaded servers; +it doesn't actually work right yet, however. Also the ports library +has new features (soft vs. hard ports; no outstanding ports +notifications) that enable server-death to be done cleanly. (I hope; +libdiskfs and ufs haven't yet been changed to use it, so libports +might not actually have the right facilities yet.) + +The translator startup routines in libfshelp have been vastly improved +(so that they can actually be used). + +Numerous bugfixes in libdiskfs, particularly relating to translator +usage. Use new magical retry type `/' when appropriate. Use new +dotdot node protocol. O_FSYNC and O_NOATIME are now honored properly. +Alternative methods of storing symlinks are now supported through new +hooks. + +The new dotdot protocol is now used by libtrivfs. Also, users of the +library are now able to set the atime and mtime when necessary. + +The special threads version of malloc has been placed back in +libthreads now that the C library uses a Mach-safe version on its own. + + +Program changes: + +The `boot' program no longer implements the tioctl interface now that +the terminal driver works. + +A bug was fixed in the handling of pgrps in `proc'. + +Many bugfixes in term. The tioctl interface is now implemented. EOF +processing is fixed; break characters now work right. Signals and +interruption are now done correctly. VDISCARD works. + +Ufs has Some bigs fixed in dir.c. Filesystem upgraded to BSD 4.4. +There are now some compatibility flags. + +New program dev.trim does a very minimal /dev (but doesn't work yet). +New program dev is an initial (but poor) attempt at a real /dev. diff --git a/hurd/history/hurd-flash5 b/hurd/history/hurd-flash5 new file mode 100644 index 00000000..041a0ef7 --- /dev/null +++ b/hurd/history/hurd-flash5 @@ -0,0 +1,23 @@ +From: mib@gnu.ai.mit.edu (Michael I Bushnell) +Message-Id: <9409210619.AA17570@churchy.gnu.ai.mit.edu> +To: "Lots of potentially interested people and" <nobody@gnu.ai.mit.edu> +Subject: New milestone acheived by the GNU Hurd +X-Tom-Swiftie: "I can't get this fire started," Tom said woodenly. + + +I have just successfully compiled and run a null C program on the +Hurd. This is using GCC native as one would normally use GCC. + +Sadly, it took quite a while (too long, in fact) to read the large +archives that make up the GNU C library, but I think I know where the +substantial inefficiency is. + +Once that is done, I would be happy to label this a "self-hosting +system". But not just yet. + +The last bug preventing this was an error in dealing with files over +about 8 M; this came about because in order to link a program one +needed the GNU C library, which is over 9M when symbols are included. + + -mib + diff --git a/hurd/history/hurd-flash6 b/hurd/history/hurd-flash6 new file mode 100644 index 00000000..e774714e --- /dev/null +++ b/hurd/history/hurd-flash6 @@ -0,0 +1,46 @@ +Return-Path: <pdxgate.cs.pdx.edu!gnu.ai.mit.edu!mib> +Received: from pdxgate.cs.pdx.edu by gnurd with uucp + (Linux Smail3.1.28.1 #14) id m0r66pm-00010fC; Fri, 11 Nov 94 17:00 PST +Received: from cs.pdx.edu by pdxgate.cs.pdx.edu (4.1/CATastrophe-9/19/94-U) + id AA05257; Fri, 11 Nov 94 16:40:48 PST +Received: from churchy.gnu.ai.mit.edu by cs.pdx.edu (4.1/CATastrophe-9/19/94-P) + id AA02600; Fri, 11 Nov 94 16:40:22 PST +Received: by churchy.gnu.ai.mit.edu (5.65/4.0) + id <AA12621@churchy.gnu.ai.mit.edu>; Fri, 11 Nov 94 16:45:35 -0500 +Received: by churchy.gnu.ai.mit.edu (5.65/4.0) + id <AA12580@churchy.gnu.ai.mit.edu>; Fri, 11 Nov 94 16:38:44 -0500 +Date: Fri, 11 Nov 94 16:38:44 -0500 +From: mib@gnu.ai.mit.edu (Michael I Bushnell) +Message-Id: <9411112138.AA12580@churchy.gnu.ai.mit.edu> +To: hurd-ann@gnu.ai.mit.edu, hurd-dev@gnu.ai.mit.edu, info-gnu@prep.ai.mit.edu +Subject: New Hurd Snapshot +X-Shopping-List: + (1) Horrendous collision devotions (2) Wondrous consolation (3) + Conscious cooking auctions +X-Filter: mailagent [version 3.0 PL19] for trent@gnurd.uu.pdx.edu + + +A new Hurd snapshot has been placed on alpha.gnu.ai.mit.edu. There +may be unforseen problems with this snapshot, so the old one has been +left. You may fetch this snapshot via anonymous FTP in the file +/gnu/hurd-snap.tar.gz. + +The Hurd requires a modified version of MiG; you can get it by +anonymous ftp to kahlua.cs.utah.edu in /pub/mach/mach4-UK02p6.tar.gz. +Note that we are not yet using Mach4 for the Hurd, but we plan to +switch as soon as its feasible. + +Other necessary software to run this snapshot include the latest +snapshot of binutils/ld/gas source from Cygnus and the latest GCC. +(Problems have been reported with GCC 2.6.1; you might want to wait +until 2.6.2 is released.) And, of course, you also need the latest +test version of the GNU C Library, found on alpha.gnu.ai.mit.edu. + +This is not yet a real release; it is certainly not up to the quality +of even a hesitant alpha release. But it may be useful for +educational value or to help with the Hurd effort. + +I will be out of town for most of the rest of the year; I will be +reading email but I may not be able to help with problems. Sorry... + + -mib diff --git a/hurd/history/hurd-flash7 b/hurd/history/hurd-flash7 new file mode 100644 index 00000000..ce6e08d2 --- /dev/null +++ b/hurd/history/hurd-flash7 @@ -0,0 +1,17 @@ +Date: Wed, 12 Apr 1995 15:08:18 -0400 +From: Michael I Bushnell <mib@gnu.ai.mit.edu> +To: hurd-ann@duality.gnu.ai.mit.edu +Subject: New Hurd Snapshot available + +A new hurd snapshot is now available from +ftp://alpha.gnu.ai.mit.edu/gnu/hurd-snap.tar.gz. + +This snapshot contains many improvements over the last one, and is +also probably easier to compile. + +This snapshot must be used with the most recent libc snapshot, +ftp://alpha.gnu.ai.mit.edu/gnu/libc-950411.tar.gz. Previous versions +of the library will not work right. + +If any files are discovered to be missing, please let me know asap. + diff --git a/hurd/history/hurd-flash8 b/hurd/history/hurd-flash8 new file mode 100644 index 00000000..555186ec --- /dev/null +++ b/hurd/history/hurd-flash8 @@ -0,0 +1,73 @@ +Date: Sun, 23 Jul 1995 16:27:46 -0400 +Message-Id: <199507232027.QAA09306@geech.gnu.ai.mit.edu> +From: Michael I Bushnell <mib@gnu.ai.mit.edu> +To: hurd-ann@gnu.ai.mit.edu +Subject: Hurd snapshot! +X-Geek-Code: (V2.1) GCS/J/M/MU/P/S/O>AT d- H-- s-: g+++ p0 !au a- w++ v+++(*) C+ ++$ UB++++$ P--- L 3- E++ N++ K++++ W-- M- V-- po-- Y+(--) t++ 5+ j++ R- G'''' tv ++ b+++ !D B-- e+ u++(*) h* f? r n y++ +X-Zippy-Says: I just had a NOSE JOB!! +Sender: owner-abshurd@cs.pdx.edu +Precedence: bulk + + +I have just put a new Hurd snapshot on alpha.gnu.ai.mit.edu in +/gnu/hurd-snap-950723.tar.gz. + +You will also need the new libc snapshot, which should appear in the +same place today. Older libc snapshots will not be happy. + +The binary images (hurd-floppy.fs.gz and hurd-image.tar.gz) have not +been updated. It is difficult to use the Hurd standalon, because the +Mach boot loaders can now no longer boot the Hurd. A new boot loader +is nearly finished. Perhaps we can make new binary images then, or a +volunteer might take over this useful work. (Hint, hint.) + +Michael + + + +Here is the NEWS: + +July 23, 1995 + +Shared libraries now work; use -static to link programs and avoid the +shared libraries. The Hurd programs are normally built static; this +will probably change soon. + +The ext2fs server now works, as do the tools to manipulate ext2fs +filesystems. A snapshot of the tools will be made soon under separate +cover. Many thanks to Ted Ts'o for his valuable work on the tools. + +Readers of the Makefiles will notice that we now generate dependencies +automatically. + +The old netserv library is gone. + +The `boot' hack has been modified slightly to avoid the normalq libc startup +files, because they no longer work with UX. + +Some small bugs have been fixed in the devio server. + +The ports library has been totally rewritten; new features permit +servers to have greater control over thread RPC's and port creation. + +The fshelp library now does most of the work for translator +interaction; it's simpler now too. Filesystems have much less work to +do; the relevant code in libdiskfs is now understanble instead of +unparseable chaos. + +The ports library provides for timeouts; the diskfs library almost +uses it, but because of a bug, it's disabled for now. + +Filesystems are now expected to sync themselves if necessary; the new +fsys_set_options RPC provides for changeing (or cancelling) the sync +intervale. The diskfs library does this for you. The update program +is no longer necessary. + +A small bug in the proc server has been hacked around; the real fix +will come later. + +Many important bugs in the C library have been fixed since the last +snapshot; perhaps all of them. ;-) + diff --git a/hurd/history/hurd-flash9 b/hurd/history/hurd-flash9 new file mode 100644 index 00000000..1ff32ba9 --- /dev/null +++ b/hurd/history/hurd-flash9 @@ -0,0 +1,39 @@ +Date: Wed, 29 Nov 1995 13:13:23 -0500 +Message-Id: <199511291813.NAA10983@duality.gnu.ai.mit.edu> +From: mib@gnu.ai.mit.edu (Michael I. Bushnell, p/BSG) +To: hurd-ann@gnu.ai.mit.edu (and others) +Subject: Announcement +X-Geek-Code: (V2.1) GCS/J/M/MU/P/S/O>AT d- H-- s-: g+++ p0 !au a- w++ v+++(*) C+ ++$ UB++++$ P--- L 3- E++ N++ K++++ W-- M- V-- po-- Y+(--) t++ 5+ j++ R- G'''' tv ++ b+++ !D B-- e+ u++(*) h* f? r n y++ +X-Windows: The Cutting Edge of Obsolescence. +Sender: owner-abshurd@cs.pdx.edu +Precedence: bulk + + +The Hurd has succesfully completed its first FTP: + +bash# ftp 128.52.46.31 +Connected to 128.52.46.31. +220 albert.gnu.ai.mit.edu FTP server (Version 5.60) ready. +Name (128.52.46.31:root): +331 Password required for root. +Password:230 User root logged in. +ftp> cd ~mib +250 CWD command successful. +ftp> get ftptest +200 PORT command successful. +150 Opening ASCII mode data connection for ftptest (16 bytes). +226 Transfer complete. +17 bytes received in 0.07 secs (0.24 Kbytes/sec) +ftp> quit +221 Goodbye. +bash# cat ftptest +this is a test. +bash# + + +Tre cool. + +Michael + diff --git a/hurd/hurd_hacking_guide.mdwn b/hurd/hurd_hacking_guide.mdwn index 0cb96f32..2ef08f8a 100644 --- a/hurd/hurd_hacking_guide.mdwn +++ b/hurd/hurd_hacking_guide.mdwn @@ -8,6 +8,16 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] -Originally written by Wolfgang Jährling, the [Hurd Hacking Guide](http://www.gnu.org/software/hurd/hacking-guide/hhg.html) -contains an overview of some of the Hurd's features. -Also contains a tutorial on writing your own [[translator]]. +Originally written by Wolfgang Jährling, the *Hurd Hacking Guide* contains an +introduction to GNU Hurd and GNU Mach programming, an overview of some of the +Hurd's features. It also contains a tutorial on writing your own +[[translator]]. + + * [HTML version](http://www.gnu.org/software/hurd/hacking-guide/hhg.html) for + browsing online, + * [PostScript version](http://www.gnu.org/software/hurd/hacking-guide/hhg.ps) + [187kB, 37 pages], + * [ASCII text + version](http://www.gnu.org/software/hurd/hacking-guide/hhg.txt) [59kB], + * [Texinfo source](http://www.gnu.org/software/hurd/hacking-guide/hhg.texi) + [60kB]. diff --git a/hurd/libstore.mdwn b/hurd/libstore.mdwn index ab649ebc..3de42be3 100644 --- a/hurd/libstore.mdwn +++ b/hurd/libstore.mdwn @@ -9,7 +9,7 @@ is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] `libstore` is more than just a thin layer between -[[GNU_Mach|microkernel/mach/gnumach]] devices (`hd0` for example) and the +[[microkernel/mach/GNU_Mach]] devices (`hd0` for example) and the device node below `/dev`... # Available Stores diff --git a/hurd/logo.mdwn b/hurd/logo.mdwn index b1030e50..fcfe22dd 100644 --- a/hurd/logo.mdwn +++ b/hurd/logo.mdwn @@ -20,6 +20,6 @@ sources](http://www.gnu.org/graphics/hurd.mf) to [[img boxes-redrawn.png]] -This symbol is also being used as a favicon for this whole wiki. +This symbol is also being used as a favicon for this web site. [[img /favicon.ico]] diff --git a/hurd/logo.png b/hurd/logo.png Binary files differdeleted file mode 100644 index a892b47d..00000000 --- a/hurd/logo.png +++ /dev/null diff --git a/hurd/ng/position_paper.mdwn b/hurd/ng/position_paper.mdwn index 3240a41d..e0f4bf60 100644 --- a/hurd/ng/position_paper.mdwn +++ b/hurd/ng/position_paper.mdwn @@ -8,7 +8,8 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] -[[NealWalfield]] and [[MarcusBrinkmann]] wrote a paper titled [*Improving -Usability via Access Decomposition and Policy -Refinement*](http://walfield.org/papers/20070104-walfield-access-decomposition-policy-refinement.pdf). -This is sometimes referred to as *the position paper*. +Neal Walfield and Marcus Brinkmann wrote a paper titled [*Improving Usability +via Access Decomposition and Policy +Refinement*](http://walfield.org/papers/20070104-walfield-access-decomposition-policy-refinement.pdf) +where they give an overview about how a future, subsequent system may be +architected. This is sometimes referred to as *the position paper*. diff --git a/hurd/gettinghelp.mdwn b/hurd/reference_manual.mdwn index 1faa94c5..5b5bff2d 100644 --- a/hurd/gettinghelp.mdwn +++ b/hurd/reference_manual.mdwn @@ -1,4 +1,5 @@ -[[meta copyright="Copyright © 2007, 2008 Free Software Foundation, Inc."]] +[[meta copyright="Copyright © 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 +Free Software Foundation, Inc."]] [[meta license="""[[toggle id="license" text="GFDL 1.2+"]][[toggleable id="license" text="Permission is granted to copy, distribute and/or modify this @@ -8,4 +9,10 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] -[[meta redir=getting_help]] +*The GNU Hurd Reference Manual* documents the architecture, the usage and the +programming of the GNU Hurd. At the moment, the manual is quite incomplete. + + * [HTML version](http://www.gnu.org/software/hurd/doc/hurd_toc.html) for + browsing online, + * [PostScript version](http://www.gnu.org/software/hurd/doc/hurd.ps) + [1020KiB, 91 pages]. diff --git a/hurd/running.mdwn b/hurd/running.mdwn index 162bc9ea..78815099 100644 --- a/hurd/running.mdwn +++ b/hurd/running.mdwn @@ -9,7 +9,7 @@ is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] * [[Distrib]] - Distributions based on the Hurd -* [[microkernel/mach/gnumach/ports/Xen]] - In Xen +* [[microkernel/mach/gnu_mach/ports/Xen]] - In Xen * [[Live_CD]] * [[QEMU]] - In QEMU * [[vmware]] (**non-free!**) diff --git a/hurd/running/debian.mdwn b/hurd/running/debian.mdwn index f291b75b..f80c1cfc 100644 --- a/hurd/running/debian.mdwn +++ b/hurd/running/debian.mdwn @@ -1,7 +1,5 @@ [[meta title="Debian GNU/Hurd"]] -[[img logo.png]] - - Debian [[FAQ]] -- Frequently Asked Questions - [[After_install]] -- Do this to get networking, new console and X - [Presentation](http://people.debian.org/~mbanck/talks/hurd_lt2004/html/) diff --git a/hurd/running/debian/logo.png b/hurd/running/debian/logo.png Binary files differdeleted file mode 100644 index 068d9584..00000000 --- a/hurd/running/debian/logo.png +++ /dev/null diff --git a/hurd/running/distrib.mdwn b/hurd/running/distrib.mdwn index fc42e862..b0a6badd 100644 --- a/hurd/running/distrib.mdwn +++ b/hurd/running/distrib.mdwn @@ -94,7 +94,7 @@ about getting applications to work (if possible). * GNU [Coding Standards](http://www.gnu.org/prep/standards.html) * [[TestSuites]] - Posix, Perl, results feedback, etc. -* [docs and papers](http://www.gnu.org/software/hurd/docs.html) +* [[Documentation]] * [[SystemAPILimits]] * [[CodeAnnouncements]] - Recent coding projects related to the Hurd diff --git a/hurd/running/gnu.mdwn b/hurd/running/gnu.mdwn index 2ae2f2ca..26d93279 100644 --- a/hurd/running/gnu.mdwn +++ b/hurd/running/gnu.mdwn @@ -1,5 +1,3 @@ -[[img logo.png]] - # <a name="The_GNU_Operating_System"> </a> The GNU Operating System The GNU Operating System, or GNU System as it is more commonly known, will be a diff --git a/hurd/running/gnu/gnu.mdwn b/hurd/running/gnu/gnu.mdwn index 2a3629d7..3ee5f657 100644 --- a/hurd/running/gnu/gnu.mdwn +++ b/hurd/running/gnu/gnu.mdwn @@ -1,5 +1,3 @@ -[[img logo.png]] - ## <a name="GNU_FSF_amp_RMS"> </a> GNU, FSF & RMS GNU stands for GNU's Not [[Unix]]. It is a project announced in 1983 by diff --git a/hurd/running/gnu/logo.png b/hurd/running/gnu/logo.png Binary files differdeleted file mode 100644 index 50c392cf..00000000 --- a/hurd/running/gnu/logo.png +++ /dev/null diff --git a/hurd/running/gnu/universal_package_manager.mdwn b/hurd/running/gnu/universal_package_manager.mdwn index 009b26bf..440f1122 100644 --- a/hurd/running/gnu/universal_package_manager.mdwn +++ b/hurd/running/gnu/universal_package_manager.mdwn @@ -127,7 +127,7 @@ OK. I will give you steps. i. Install a GNU System by folowing [[these_instructions|setup]] -ii. Read about GNU Design <http://www.gnu.org/software/hurd/hurd-paper.html> +ii. Read about GNU Design: [[Towards_a_New_Strategy_of_OS_Design|documentation/hurd-paper]] iii. Read about translators <http://www.debian.org/ports/hurd/hurd-doc-translator> diff --git a/hurd/status.mdwn b/hurd/status.mdwn index a84d7c45..b4ece046 100644 --- a/hurd/status.mdwn +++ b/hurd/status.mdwn @@ -1,4 +1,5 @@ -[[meta copyright="Copyright © 2007, 2008 Free Software Foundation, Inc."]] +[[meta copyright="Copyright © 2001, 2002, 2007, 2008 Free Software Foundation, +Inc."]] [[meta license="""[[toggle id="license" text="GFDL 1.2+"]][[toggleable id="license" text="Permission is granted to copy, distribute and/or modify this @@ -8,19 +9,44 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] -The Hurd team doesn't create hurd-only releases, but instead relies -on a distribution done by folks from **Debian**. +The Hurd, together with the GNU Mach microkernel, the GNU C Library +and the other GNU and non-GNU programs in the GNU system, provide a +rather complete and usable operating system today. It may not be ready +for production use, as there are still many bugs and missing features. +However, it should be a good base for further development and +non-critical application usage. + +The GNU system (also called GNU/Hurd) is completely self-contained +(you can compile all parts of it using GNU itself). You can run +several instances of the Hurd in parallel, and debug even critical +servers in one Hurd instance with gdb running on another Hurd +instance. You can run the X window system, applications that use it, +and advanced server applications like the Apache webserver. + +On the negative side, the support for character devices (like sound +cards) and other hardware is mostly missing. Although the POSIX +interface is provided, some additional interfaces like POSIX shared +memory or semaphores are still under development. + +All this applies to the current development version, and not to the +last release (0.2). We encourage everybody who is interested to try +out the latest development version, and send feedback to the Hurd +developers. + + +The Hurd team doesn't create Hurd-only releases, but instead relies +on a distribution done by folks from *Debian*. That Debian version closely tracks the progress of the Hurd (and often includes many new features), so little would be gained by creating an official pure Hurd release. -The Debian GNU/Hurd [[distribution|running/debian]] offers **livecds and qemu images** +The Debian GNU/Hurd [[distribution|running/debian]] offers *LiveCDs and QEMU images* to test-drive the Hurd in a real life system with access to about 50% of the Debian software archive. The most recent version of the Debian port at the time of writing -is **Debian GNU/Hurd K16**. +is *Debian GNU/Hurd K16*. That said, the last official release of the Hurd @@ -34,3 +60,4 @@ already expect delays; to disappoint them in this way as well would be unfortunate. Moreover, it would lessen the possibility that they would want to try the Hurd again in the future. + diff --git a/hurd/subhurd.mdwn b/hurd/subhurd.mdwn index 8816e312..d2b80cf9 100644 --- a/hurd/subhurd.mdwn +++ b/hurd/subhurd.mdwn @@ -118,5 +118,4 @@ characteristic thread counts. Read about using a subhurd for [[debugging_purposes|debugging/subhurd]]. -Roland's [tutorial](http://www.gnu.org/software/hurd/howto/subhurd.html) on -setting up sub-hurds. +Roland's tutorial about [[running_a_subhurd]]. diff --git a/hurd/subhurd/running_a_subhurd.mdwn b/hurd/subhurd/running_a_subhurd.mdwn new file mode 100644 index 00000000..5d9693cd --- /dev/null +++ b/hurd/subhurd/running_a_subhurd.mdwn @@ -0,0 +1,42 @@ +[[meta copyright="Copyright © 1998, 1999, 2007, 2008 Free Software Foundation, +Inc."]] + +[[meta license="""[[toggle id="license" text="GFDL 1.2+"]][[toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled +[[GNU_Free_Documentation_License|/fdl]]."]]"""]] + +[[meta title="Running a Subhurd"]] + +By Roland McGrath. + +The most useful thing you can do when trying to troubleshoot the boot +sequence of the Hurd is try to run your the system in a +sub-hurd, while watching it using ps and gdb from the working hurd. Since +the sub-hurd is never going to make it all the way up, you don't even +really need to make a separate filesystem for it; you can just boot the +sub-hurd read-only on your main root filesystem if you like. + +The way to boot the sub-hurd is with `boot`. I would suggest something +like this: + + boot -d -I -Tdevice /boot/servers.boot hd0s6 + +The -d says to pause before the start-up of each server and wait for you to +hit return, which gives you time to go attach gdb to the task before it +starts running. The -I says to leave the terminal signals normal, so +hitting C-z will suspend boot rather than sending a C-z to the virtual +console device of the sub-hurd. (Note that suspending boot does not +suspend the sub-hurd, just boot itself; boot acts as the server for device +access from the sub-hurd, so the sub-hurd's attempts to write to its +console or open devices block while boot is suspended.) + +When you do `ps -A` on the main hurd, the sub-hurd tasks will appear as +unknown processes. You can figure out which is which just by looking at +the order of unknown processes that appear with higher PIDs than the boot +process. They appear in the order you see in the "bootstrap: ..." +messages, i.e. the first unknown after boot will be ext2fs.static, the +second exec, then init, then proc. diff --git a/hurd/translator.mdwn b/hurd/translator.mdwn index b9952931..1a987b09 100644 --- a/hurd/translator.mdwn +++ b/hurd/translator.mdwn @@ -40,9 +40,12 @@ Also there is an [[writing/example]] about how to write a simple translator. See some [[examples]] about how to use translators. +Marcus Brinkmann has written a document about [[documentation/translators]]. + # Existing Translators +* [[auth]] * [[pfinet]] * [[pflocal]] * [[hostmux]] diff --git a/hurd/running/creating_image_tarball.mdwn b/hurd/translator/auth.mdwn index 2938c79a..73e7e025 100644 --- a/hurd/running/creating_image_tarball.mdwn +++ b/hurd/translator/auth.mdwn @@ -8,4 +8,6 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] -[[meta redir=debian/creating_image_tarball]] +[[*The_Authentication_Server*|documentation/auth]], the transcript of a talk +about the details of the authentication mechanisms in the Hurd by Wolfgang +Jährling. diff --git a/hurd/what_is_the_gnu_hurd.mdwn b/hurd/what_is_the_gnu_hurd.mdwn new file mode 100644 index 00000000..b125fc48 --- /dev/null +++ b/hurd/what_is_the_gnu_hurd.mdwn @@ -0,0 +1,42 @@ +[[meta copyright="Copyright © 2001, 2002, 2003, 2004, 2005, 2007, 2008 Free +Software Foundation, Inc."]] + +[[meta license="""[[toggle id="license" text="GFDL 1.2+"]][[toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled +[[GNU_Free_Documentation_License|/fdl]]."]]"""]] + +[[meta title="What Is the GNU Hurd?"]] + +The Hurd is the GNU project's replacement for the [[Unix]] kernel. + +The Hurd is firstly a collection of protocols formalizing how different +components may interact. The protocols are designed to reduce the mutual +[[trust]] requirements of the actors thereby permitting a more +[[extensible|extensibility]] system. These include interface definitions to +manipulate files and directories and to resolve path names. This allows any +process to implement a file system. The only requirement is that it have +access to its backing store and that the [[principal]] that started it own the +file system node to which it connects. + +The Hurd is also a set of servers that implement these protocols. +They include file systems, network protocols and authentication. +The servers run on top of the [[microkernel/Mach]] [[microkernel]] and use +Mach's [[microkernel/mach/IPC]] mechanism to transfer information. + +The Hurd supplies the last major software component needed for a complete +[[GNU_operating_system|running/gnu]] as originally conceived by Richard +M. Stallman (RMS) in 1983. The GNU vision directly drove the creation and has +guided the evolution of the [Free Software Foundation](http://fsf.org/), the +organization that is the home of the [GNU project](http://gnu.org/gnu/). + +The Hurd development effort is a somewhat separate project from the +[[Debian_GNU/Hurd|hurd/running/debian]] port. + + +Read about what the GNU Hurd is [[gramatically_speaking]]. + +Read about the [[origin_of_the_name]]. diff --git a/hurd/faq/gramatically_speaking.mdwn b/hurd/what_is_the_gnu_hurd/gramatically_speaking.mdwn index 7aa3edac..4a2ddc67 100644 --- a/hurd/faq/gramatically_speaking.mdwn +++ b/hurd/what_is_the_gnu_hurd/gramatically_speaking.mdwn @@ -9,19 +9,27 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU_Free_Documentation_License|/fdl]]."]]"""]] -[[meta title="Grammatically speaking, what is the Hurd?"]] +[[meta title="Grammatically speaking..."]] -*Hurd*, as an acronym, stands for *Hird of [[Unix]]-Replacing Daemons*. *Hird*, in -turn, stands for *Hurd of Interfaces Representing Depth*. +> [[It's_time_to_explain|origin_of_the_name]] the meaning of *Hurd*. +> +> *Hurd* stands for *Hird of [[Unix]]-Replacing Daemons*. +> And, then, *Hird* stands for *Hurd of Interfaces Representing Depth*. -We treat *Hurd* as a title rather than as a proper name: it requires an -article, as in *the Hurd*. For instance: *The ext2 filesystem is provided by -the Hurd, not by Mach.* Note that all of the following are incorrect: *Hurd*, -*HURD*, *The HURD*, and *the hurd*. +The Hurd has its share of linguistic debate. The subject of proper usage comes +up quite often. -We write *the GNU Hurd* instead of *the Hurd* when we want to emphasize that -the Hurd is a GNU package. Once this has been made clear, we usually use the -shorter form, without *GNU*. +Although [[Thomas_Bushnell_states|origin_of_the_name]] that the word *Hurd* is +an acronym; we do not treat it as such, but rather as a concrete noun. We +treat *Hurd* as a title rather than as a proper name: it requires an article, +as in *the Hurd*. For instance: *The ext2 filesystem is provided by the Hurd, +not by Mach.* Note that all of the following are incorrect: *Hurd*, *HURD*, +*H.U.R.D.*, *The HURD*, and *the hurd*. + +Since the Hurd is part of the GNU Project, we also refer to it as *GNU Hurd* +which is treated as a proper noun. We write *the GNU Hurd* instead of *the +Hurd* when we want to emphasize that the Hurd is a GNU package. Once this has +been made clear, we usually use the shorter form, without *GNU*. The whole operating system includes not only the kernel and the system servers, but also many more programs. This system is called *GNU*, or *the GNU @@ -40,3 +48,7 @@ singular, capitalized as in English. When we are referring to the microkernel, we say *Mach* and use it as a proper noun. For example: *Mach uses the device drivers found in version 2.0.x of Linux.* We sometimes say *the Mach microkernel* instead of just *Mach*. + + +To pronounce the word *Hurd*, you should say the English word *herd*. This is +pronounced as *hɚd* using the International Phonetic Alphabet. diff --git a/hurd/what_is_the_gnu_hurd/origin_of_the_name.mdwn b/hurd/what_is_the_gnu_hurd/origin_of_the_name.mdwn new file mode 100644 index 00000000..3527703a --- /dev/null +++ b/hurd/what_is_the_gnu_hurd/origin_of_the_name.mdwn @@ -0,0 +1,50 @@ +[[meta copyright="Copyright © 1996, 1997, 1998, 2002, 2003, 2004, 2007, 2008 +Free Software Foundation, Inc."]] + +[[meta license="""[[toggle id="license" text="GFDL 1.2+"]][[toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled +[[GNU_Free_Documentation_License|/fdl]]."]]"""]] + +[[meta title="Origin of the Name"]] + +[According to Thomas +Bushnell](http://web.cecs.pdx.edu/~trent/gnu/hurd/hurd-name), the primary +architect of the Hurd: + +> It's time to explain the meaning of *Hurd*. +> +> *Hurd* stands for *Hird of [[Unix]]-Replacing Daemons*. +> And, then, *Hird* stands for *Hurd of Interfaces Representing Depth*. +> +> We have here, to my knowledge, the first software to be named by a +> pair of mutually recursive acronyms. + +[Quoting](http://mail.gnu.org/archive/html/help-hurd/2002-10/msg00099.html) +him further: + +> The name *Hurd* was invented by me, as an alternate spelling for the English +> word *herd*. *Hird* is just another alternate spelling for the same word. +> By the [[normal_rules_of_English_orthography|gramatically_speaking]], they +> all have the same pronunciations. + + +--- + +<!-- TODO. Source? Or remove? --> + +In other contexts: + +One contributor from Norway described two other uses of Hird. + + * "the kings men", a name given to the men accompanying the Norwegian kings at about + year 1000 and on. + + This was later coined by V. Quisling when he formed a party with + nationalistic traits to denote a set of helpers promoting his agenda of + national and Nordic ideas. + + * a symbol of collaboration with the (German) enemy used in World War II. |