diff options
Diffstat (limited to 'hurd/faq')
| -rw-r--r-- | hurd/faq/how_about_drivers.mdwn | 17 | ||||
| -rw-r--r-- | hurd/faq/how_to_switch_microkernels.mdwn | 15 | ||||
| -rw-r--r-- | hurd/faq/old-stuff.mdwn | 45 | ||||
| -rw-r--r-- | hurd/faq/old_faq.txt | 562 | ||||
| -rw-r--r-- | hurd/faq/old_hurd_faq.txt | 289 | ||||
| -rw-r--r-- | hurd/faq/release.mdwn | 15 | ||||
| -rw-r--r-- | hurd/faq/slash_usr_symlink.mdwn | 20 | ||||
| -rw-r--r-- | hurd/faq/smp.mdwn | 17 | ||||
| -rw-r--r-- | hurd/faq/still_useful.mdwn | 46 | ||||
| -rw-r--r-- | hurd/faq/top.mdwn | 16 | ||||
| -rw-r--r-- | hurd/faq/which_microkernel.mdwn | 19 |
11 files changed, 1061 insertions, 0 deletions
diff --git a/hurd/faq/how_about_drivers.mdwn b/hurd/faq/how_about_drivers.mdwn new file mode 100644 index 00000000..0556fd28 --- /dev/null +++ b/hurd/faq/how_about_drivers.mdwn @@ -0,0 +1,17 @@ +[[!meta copyright="Copyright © 2009 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 drivers does GNU/Hurd have?"]] + +Currently, Mach integrates drivers from Linux 2.0 through some glue code. As +it's very old, that limits hardware support a lot, of course. We are however +working on using the DDE toolkit to run linux drivers in userland processes, +which provides both long-term support for new hardware and safety against driver +bugs. diff --git a/hurd/faq/how_to_switch_microkernels.mdwn b/hurd/faq/how_to_switch_microkernels.mdwn new file mode 100644 index 00000000..21f7a371 --- /dev/null +++ b/hurd/faq/how_to_switch_microkernels.mdwn @@ -0,0 +1,15 @@ +[[!meta copyright="Copyright © 2009, 2010 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="How difficult would it be to switch to another microkernel?"]] + +One would have to reimplement the `mach/` and `sysdeps/mach/` parts of +[[glibc]] and [[libpthread]]. Quite a few other Hurd tools also assume a +[[microkernel/Mach]] kernel and would have to be adapted or rewritten. diff --git a/hurd/faq/old-stuff.mdwn b/hurd/faq/old-stuff.mdwn new file mode 100644 index 00000000..df2058c0 --- /dev/null +++ b/hurd/faq/old-stuff.mdwn @@ -0,0 +1,45 @@ +In addition to the [general FAQ](http://www.gnu.org/software/hurd/docs.html#TOCfaq) there are the following typical newbie questions. (There is an [updated version](http://tuxou.ouvaton.org/hurd/) which is not official yet.) + +If you still have problems, do not hesitate to make use of the [[mailing lists]] or the [[IRC]]. + +* **_You say GNU, don't you mean GNU/Hurd?_** + * Yes and no. GNU refers to the system as a whole, while GNU/Hurd is more specific, saying that it is the GNU system running on the Hurd -- to differentiate it from the GNU system running on Linux, GNU/Linux. Also see [[GNU/GnuNames]] + +* **_What editor can I use?_** + * `nano` is the default editor on a fresh install, not `ae`, but a lot of editors are available. + +* **_Why can't I get the answers I need from Hurd hackers?_** + * This [document](http://www.catb.org/~esr/faqs/smart-questions.html) may help you understand some developers attitudes and social norms. + +* **_Where are the virtual consoles I use when running Linux?_** + * You need to [use screen](http://www.gnu.org/software/hurd/faq.en.html#q4-6) instead, also available when running GNU/Linux. + * The [new console](http://lists.debian.org/debian-hurd/2002/debian-hurd-200209/msg00054.html) by Marcus Brinkmann could also be used. It supports the Alt-Fn keys for switching like in Linux. NOTE: that message has an error in the configuration steps, it says `/dev/vts` when it means `/dev/vcs`. A more up-to-date howto is [[console]]. + +* **_What is a translator?_** + * The official FAQ [answers](http://www.gnu.org/software/hurd/faq.en.html#q4-2) this question by a reference to [hurd-doc-translator](http://www.debian.org/ports/hurd/hurd-doc-translator). + +* **_Where's the sauce?_** + * It's on [Savannah](http://savannah.gnu.org). See also the [GNU Development Resources](http://www.gnu.org/software/devel.html), for more information. + +* **_What is this "libio" stuff?_** + * There was an ABI change for glibc0.3. It's recommended you reinstall your GNU/Hurd system if you run a system installed before the summer of 2002. This is a similar cause for the various Linux distributions who changed from libc5 to libc6 or glibc2 around 1998. + +* **_What is GNU Mach vs. oskit-mach?_** + * These are different versions of the Mach microkernel that supports the Hurd that runs on top of it. For more info, see [[Mach]] + +* **_What software is available for GNU?_** + * Most (2/3) packages from [Debian](http://www.debian.org/) [GNU/Linux](http://www.gnu.org/gnu/linux-and-gnu.html) which aren't linux-specific ([Packages That Won't Be Ported](http://www.debian.org/ports/hurd/hurd-devel-debian)) are expected to work on GNU/Hurd too. See the database in <http://packages.debian.org/>. Notably, [GNOME](http://www.gnome.org), and [KDE](http://www.kde.org) work. See the [[porting/guidelines]] document for some common build problems and their solutions. + * If you can't fetch a package with "apt-get install ", try building it from source: "apt-get source && cd <package\_dir> && debian/rules binary". + * As of April 2010, 65% of Debian packages have been ported on the Hurd. Of course, bug testing is welcome. + +* **_How do I initialize a serial console on the Hurd?_** + * You can try out the Serial Howto at <http://www.nongnu.org/thug/serial-howto.txt> + * For a real serial console at boot time you need to rebuild your GNUmach 1.x kernel. For more info see the Utah release notes at [http://www.cs.utah.edu/flux/mach4-i386/html/mach4-UK22.html#serial\_console](http://www.cs.utah.edu/flux/mach4-i386/html/mach4-UK22.html#serial_console) + +* **_Will GNU work in Vmware?_** + * It's highly recommended and easier to get a full image for qemu. See [[Distrib]] + * It didn't use to, [Hurd bootstrap fails](http://lists.debian.org/debian-hurd/2002/debian-hurd-200207/msg00069.html). Vmware is not [free software](http://www.gnu.org/philosophy/free-sw.html) and it is [[Distrib/VmWare]]. We recommend to use [free](http://www.gnu.org/philosophy/free-sw.html) alternatives, like [[Distrib/BochsEmulator]]. + * A faster, more widespread and [free](http://www.gnu.org/philosophy/free-sw.html) recent alternative is [QEMU][[running/QEMU]]. You can find more informations on [[running/QEMU]]. + * If someone prefers using VMWare: + * It works with VMWare Workstation 4.0.5 build-6030. + * Running Debian GNU/HURD in VMWare works for me -- [[Main/MichaelAblassmeier]] - 03 Mar 2004 diff --git a/hurd/faq/old_faq.txt b/hurd/faq/old_faq.txt new file mode 100644 index 00000000..617d7661 --- /dev/null +++ b/hurd/faq/old_faq.txt @@ -0,0 +1,562 @@ +[[!meta copyright="Copyright © 2001, 2002, 2003, 2004, 2005, 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]]."]]"""]] + + Frequently Asked Questions about the GNU Hurd + +This document attempts to answer the questions that most often plague +users when they are talking about, installing, using, compiling and +developing the GNU Hurd as well as its binary distribution Debian +GNU/Hurd. Be sure to read this before asking for help. + +The GNU Hurd is under active development and a stable version has not +yet been released. Be aware that: there is a lot of work yet to be +completed; you will find bugs; your system will crash. That said, there +is a lot of room for contributions at all levels: development of the +Hurd and Mach proper, porting applications, writing documentation and, +most importantly, user feedback. + +Should you have a question that is not answered by this document and you +feel that it should be, submit it and, if possible, with an answer. + +Each section is copyright its respective author(s). Permission is +granted to copy, distribute and/or modify this document under the terms +of the GNU Free Documentation License, Version 1.1 or any later version +published by the Free Software Foundation; with no Invariant Sections, +with no Front-Cover Texts and with no Back-Cover Texts. A copy of the +license is included in the file COPYRIGHT. + + Neal H Walfield + neal@cs.uml.edu + +? Installation + +?? What partition type should I use for my GNU/Hurd partitions? + +{MB} You should use an ext2 filesystem. Alternatively, you may use BSD +style ufs. The partition type number for ext2fs is 0x83 (this is the +same as in Linux), not 0x63 (GNU HURD). Thomas explains why 0x63 is the +wrong choice: + + One day we may have a new filesystem format, which would + probably be called the GNU Hurd filesystem format, and might + well use that partition code. + +Regardless, as Roland points out, it is always an error to use that code +for an ext2fs partition, + +?? How do I name partitions? + +{MB,NHW} I knew you would ask this. If I had to reduce this FAQ to only +one question, I'd choose this one. It is pretty easy, but you have to +know that there are actually several incompatibly naming convention. + +First, the Hurd: if the disk is question is a SCSI disk, you must know +the SCSI device number; if it is an IDE disk, you must know what +controller the disk is on and whether it is a master or a slave. The +Hurd uses the BSD naming convention which, is to say, disks are ordered +according to their physical location, numerically, starting from zero. +This naming scheme is quite similar to that found in Linux. There, the +master disk on the primary controller is designated as `hda' and the +slave as `hdb'. On the secondary controller, the master and the slave +are designated by `hdc' and `hdd' respectively. Under the Hurd, `hda' +would become `hd0', `hdb' would be referred to as `hd1', etc. + +In the Hurd, like in BSD, partitions are called `slices' and are +numbered starting from one. Thus, to name a particular partition, we +take the disk name, append a `s' and the partition number. Again, this +is similar to Linux except, there is no `s'. For instance, `hda1' would +become `hd0s1'. + +GRUB, the boot loader, uses a completely different nomenclature: it +probes the BIOS and appends each disk in turn to an array. Both disks +and partitions are enumerated using zero based arrays. The format is: +`hd (<disk>, <partition>)'. Thus, `hd (0, 1)' refers to the second +partition on the first drive detected by the BIOS. As Grub now has tab +completion, there is not a lot of guess work. + +?? Can I use partitions larger than 2GB? + +{MB} No, not currently. The filesystem servers need to be changed to +not map the whole store into memory, which is not too difficult. For +large files, some interfaces need to be changed, which is a bit harder +but still doable. + +?? How much swap do I need? + +{NHW} Generally, a lot; once you run out, Mach panics. I have at least +128MB of ram and 256MB of swap on all of machines running GNU/Hurd. + +?? Can I share swap space between GNU/Linux and GNU/Hurd? + +{NHW} Yes. The default pager recognises and respects Linux swap +partitions. It will also swap to a raw partition, i.e. anything that it +does not recognize as Linux swap. Therefore: BE CAREFUL. + +?? Why do I get ``Operation not permitted error''? + +{MB} You forgot to set the file system owner of the GNU/Hurd partition to +``hurd''. The Hurd uses additional information in the inodes to set +translators. To make this work, the partition must be marked as ``owned +by the Hurd''. This is normally done by passing the `-o hurd' option to +`mke2fs' when creating ext2 system from other operating systems +(filesystems created in GNU/Hurd automatically enable this option). +If you failed to do this, you can still use the `e2os' script. + +?? After `native-install' is finished, I had to write tthhiiss + wwaayy. In particular, I had to type `rreebboooott' to reboot. + +{MB} Funny, isn't it? In addition to the rescue `term' server in +`/tmp/console', another `term' server got started and is clobbing the +keyboard input. After a reboot this problem vanishes as only one `term' +server will remain. If `tar' would support translator, we would not +have this problem... Even if you don't experience this problem right +after the installation, reboot immediately so you don't hit this bug by +accident. + +? Setup + +?? How do I add a swap partition? + +{MB} A swap partition is also called a paging file. Usually, it is +sufficient to add the swap partition to `/etc/fstab', just as you would +under Linux. You can swap to a Linux swap partition and the Hurd will +honour the Linux swap signature (both versions). The Hurd will just as +happily swap to any other raw disk space and overwrite anything it +finds. So, be careful! + +If you want to swap to a file or make sure that it checks the Linux swap +signature before, you need to edit `/boot/servers.boot'. The syntax is +the partition device file name plus, optionally, the swap file inside an +ext2fs partition, followed by a space and then one of: +`$(add-raw-paging-file)', `$(add-linux-paging-file)', +`$(add-paging-file)'. The first works with any partition or file and +does not honour any swap signature or other data. The second has a +safety check and only uses the file if a Linux swap signature is found. +The third looks for a swap signature first and falls back to raw paging +if it failed to find one. This is also the default for entries in +`/etc/fstab'. + +?? How do I set up a network? + How do I set up a loopback device? + +{MB} In the former case, be sure that GNU Mach detected your network +card. Either way, you need to setup `pfinet'. Documentation can be +found at: + + http://www.debian.org/ports/hurd/hurd-doc-server#pfinet + +Don't forget to fill in `/etc/resolv.conf', `/etc/hosts', etc. + +Of course, you only need to do this if the installation routine didn't +do it for you. + +?? Can I use the GNU/Linux version of `e2fsck' on a GNU/Hurd partition? + +{MB} Yes, at least since `e2fsprogs-1.05'. Check this with `e2fsck -V' +first. + +{NHW} Do not try to defrag your partition as this utility does not know +about translators. + +?? Why are pipes not working? + +{MB} `settrans -fgc /servers/socket/1 /hurd/pflocal' should help. + +? Usage + +?? Where is the documentation? + +{NHW,MM} There are neither man pages nor info nodes for the Hurd +translators and commands. Documentation lives inside of the binaries +and can be found by passing the `--help' option to a given command. +For instance: + + # /hurd/ext2fs --help + +will tell you what types of options the ext2fs translator accepts. + +The GNU/Hurd User's Guide and the GNU Hurd Reference Manual both +provide some help about the usage of and concepts behind the GNU Hurd. +You can find them, among others, at: + + http://www.gnu.org/software/hurd/docs.html + +?? What is a translator? + +{MB} There is a text about translators available at: + + http://www.debian.org/ports/hurd/hurd-doc-translator + +Read this and ask further questions on the mailing lists. + +?? What is the login shell? + +{MB} The Hurd has the concept of a not-logged in user. This user has +neither user ids nor groups ids. This stems from the fact that the Hurd +supports uid and gid sets and one possibility is, of course, the empty +set. Rather than deny access in this case, filesystems in the Hurd offer a +fourth permission triplet (i.e. rwx) which is used to determine the +privileges for users with no credentials. This, however, needs to be +enabled on a file by file basis. By default, the `other' permission +triplet is used. + +The Hurd login shell is a shell running with neither uids nor gids. To +restrict access to your files, either enable and change the fourth +permission triplet or change the login shell of the `login' user in the +password file to `/bin/loginpr' which implements the standard login +prompt. + +?? How do I use non-US keyboard bindings? + +{NHW,FH} Take a look at: + + http://www.xs4all.nl/~mgerards/xkb8.tar.gz + +If you want a Debian package, you can add to your +'etc/apt/sources.list' + + deb http://debian.duckcorp.org/unstable/binary-hurd-i386/ ./ + +and then run + + apt-get install console-driver-xkb. + +?? How do I enable color on the console? + +{NHW} If you are using the GNU Mach microkernel, you can set your +terminal to `mach-color'. For instance: + + # export TERM=mach-color + +?? How can I enable virtual consoles? + +{AMS} This can be done by running the following command: + + console -d vga -d pc_kbd -d generic_speaker /dev/vcs + +If something went wrong, or if you just wish to exit the Hurd console +then hitting C-A-<backspace> will exit it. + +?? What is the status of X? + +{MB} It works! The packages are available at any Debian ftp mirror. +XFree86 4.0.2 is available, as are some of the v3 servers. Instructions +on how to use the packages are in the mailing list archive (link follow +later). + +?? Why does X not work? + +{MB} Try `export LD_LIBRARY_PATH=/usr/X11R6/lib'. This is a linker +issue. GNU/Hurd expects that `RPATH' is used, however, Debian takes +certain measures to avoid this. Note that this does not cut it for suid +binaries because of security implications. We expect to rectify this +by using `RUNPATH', which is specified in the new ELF standard. + +?? What are these strange pids `2' and `3'? + +{MB} Two is the kernel, three is the default pager and four is the root +filesystem. + +?? Why does `ps aux' give me strange output? + +{MB,MM} Try `ps Aux'. Indeed, under GNU/Hurd, `ps aux' doesn't list +all processes: it omits the session and group leaders, and the +processes without parent. + +?? I have a hung process that I want to kill, however, `ps' is now + hanging too. + +{MB} Interrupt it and pass it the `-M' option. + +{NHW} By default, `ps' gathers information from both the proc server and +the processes themselves (via their message port). If a process it +hung, it will not be able respond to its message port and thus, ps will +wait forever. The `-M' option instructs ps to not gather information +that would require use of the message port. + +?? Where are ... + +{MB} `fdisk' and `dmesg' are not yet ported. + +Instead of `free', use `vmstat' and `vminfo'. + +For kernel messages, read `/dev/klog' directly. Note, once you read +this, it is gone forever. + + +?? Is there a `/proc' filesystem? + +{MB} No. Maybe there will be an emulation filesystem someday for +programs that rely it. If you are wondering about the empty `/proc' +directory, this is a relict from a Debian GNU/Linux package +(specifically, `base-files'). + +You can probe for existing hardware devices with the devprobe utility. + +?? Why does the command `df' not work? + +{NHW} It does, you just have to tell it what filesystem to query. E.g. + + # df / + +?? Why are my translators dying? + +{NHW} Try passing the `-ap' flag to settrans. By default, settrans only +sets a passive translator, therefore, no output will show up on your +terminal. Using `-ap', however, sets both the active and the passive +translator which, means that the translator starts immediately and its +stderr is connected to you terminal. + +Additionally, the biggest problem is passing relative paths to passive +translators. You cannot predict what the current working directory of a +translator will be when it is setup as a passive translator. + +?? Why can I `read' a directory? + +{MB} It is important to understand that there is nothing special about a +directory under the Hurd, it is just another file. This fits in with +the translator concept where a translator can appear as a directory but +provide also as a file. + +? Trouble shooting + +?? When the APM support in the BIOS spins down my disk drives, the + Hurd is unable to wake up. What's wrong? + +{MB} APM is not supported in the current version of GNU Mach, sorry. +Please disable APM in your BIOS setup. + +?? What are these messages referring to `default pager', `paging', + and `pager request'? + +{MB} The default pager handles virtual memory allocation. If it can't +allocate a new memory page because you are out of memory, some terrible +things may happen. Whenever you get errors referring to any of these, +you either need more memory (make sure you have swap) or you have found +a memory leak. + +?? What is a gratuitous error? + +{MB} This comes from `strerror(EGRATUITOUS)'. If you check glibc's +documentation, it will say that this error code has no purpose. This, +however, is not quite true. You only get this when something terrible +happens. Thomas explains: + + More precisely `EGRATUITOUS' officially means that some server + has responded in an impossible or protocol-violating fashion. + There are some cases in the Hurd where `EGRATUITOUS' is returned + and probably something else should be chosen instead. + +If you can reproduce this error message, please report it. + +?? What does ``computer bought the farm'' mean ? + +{FH} This message is the text that corresponds to the errno code +`EIEIO'. Roland McGrath explains: + + That message is not output by any particular servers at + particular times; rather it is the perror text for the errno + code EIEIO, which is returned by various RPCs and functions + for a variety of "hopeless" error conditions. + + +?? What does ``/dev/hd0s1: MOUNTED READ-ONLY; MUST USE `fsysopts + --writable''' mean? + +{NHW} In this case, /dev/hd0s1 was not unmounted cleanly. The Hurd +will, on boot up, run ``fsck -p'' on any partitions that it finds in +/etc/fstab, so, you may want to consider adding this partition to that +file. If you are sure that the partition is fine, you can run: + + # fsysopts /home --writable + +to ask the translator sitting on /home to change from read-only to +read/write mode. Note that the command is being sent to the filesystem +and not the store (e.g. /dev/hd0s1). + +?? When GNU/Hurd crashes, GNU Mach automatically reboots. Is + there anyway I can make it pause so I can write down the error? + +{MB} Pass the `-H' option to init (add it to the boot command line), and +`init' will tell Mach to enter the kernel debugger instead to rebooting +it. At the debugger prompt (`db>'), you can type `reboot' any time to +reboot the system. + +? Porting + +?? What programs have been ported? + +{NHW} A lot, take a look at the Debian archive. Many programs, however, +do not necessarily need to be ported; they have just never been +compiled. + +?? Is porting easy? + +{NHW} Porting applications to GNU/Hurd is relatively easy assuming the +application is POSIX compliant as GNU/Hurd does its best to be a +conforming operating system. + +The most common error made by programmers is assuming the MAXPATHLEN and +PATH_MAX are defined. On most operating systems this is set to a few +thousand, however, on GNU/Hurd, there is no maximum and thus, this is +not set. The correct thing to do is to submit a patch to the upstream +author that allocates memory dynamically. + +?? How can I help? + +{NHW} A effort to compile all of the Debian packages is underway by Jeff +Bailey. Take a look at: + + http://people.debian.org/~jbailey/oasis/group/Debian/index.html + +to see what has been done and how you can help. + +? Compiling + +?? Where can I get the source? + +{AMS} Instructions on how to download the CVS tree from Savanah are +avaiable at https://savannah.gnu.org/cvs/?group=hurd + +{NHW} To get the source to the latest debian package, look on any +debian mirror. + +?? Can I cross compile? + +{NHW} Yes. If you are running Debian GNU/Linux on IA32, this is quite +easy as there is a cheap cross compiler available; all that is required +is installing the gcc-i386-gnu and mig-i386-gnu Debian packages. When +running configure, you will have to specify tools directly: + + # MIG=/usr/bin/i386-gnu-mig CC=/usr/bin/i386-gnu-gcc \ + ../src/hurd/configure ... + +If you are running another distribution, you will have to do this the +long way. You can find instructions at the Cross Compiling HOW-TO +available at: + + http://hurddocs.sourceforge.net/howto/cross.html + +Farid Hajji <farid.hajji@ob.kamp.net> also talks about his experiences +at: + + http://lists.debian.org/debian-hurd-0012/msg00062.html + +?? Any general tips? + +{NHW} Yeah, building in the source tree is untested. Try: + + # ../src/hurd/configure ... + +? Development + +?? What is OSKit-Mach? + +{NHW,FH} There are two versions of GNU Mac that are in use: GNU Mach +1.x and GNU Mach 2.x, formerly known as OSKit-Mach. The former uses +the drivers from Linux 2.0.x while the latter uses the University of +Utah's OSKit library for drivers. You can find out more about the +OSKit library at: + + http://www.cs.utah.edu/flux/oskit + +GNU Mach 2.x is usable, but some things are still missing or not +working, like the serial port and scsi drivers. This is why GNU Mach +2.0 hasn't released yet and the two versions coexist. + +?? Where is the documentation? + +{NHW} There were several books written on the Mach kernel. The +information that they contain is still mostly pertinent and should be +considered required reading for potential hackers. They can be found +at: + + http://www.cs.cmu.edu/afs/cs/project/mach/public/www/doc/publications.html + +The documentation for the Hurd is quite inadequate. The starting of a +book, ``The GNU Hurd'' is in the doc directory in the Hurd source. You +can read this using: + + # info hurd + +The authoritative place is, of course, the source code; that does not, +however, mean that we would not welcome more documentation. To get +started, take a look at <hurd>/doc/navigating. + +?? How do I make sure that my code is POSIX compliant? + +{NHW} Unfortunately, you have to buy the POSIX standard from IEEE. The +Single Unix Specification version 2, a superset of POSIX, is available +for free on the Internet. Try: + + http://www.unix-systems.org/online.html + +?? Who do I submit patches to? + +{NHW} If they are against the Hurd, Mach or MiG, send a patch to the +bug-hurd mailing list. + +If they are against other packages, the Debian BTS is a good place. In +this case, be sure to advise the debian-hurd mailing list of the bug. + +?? In what format should patches for the Hurd and GNU Mach be? + +{MB} All patches should be sent in unified context diff format (option +`-u' to GNU diff). It is helpful for us if you also use the `-p' +option which includes information about the function changed by a +patch. Changes that are similar can be grouped together in one file, +but unrelated changes should be sent in seperate files. The patches +can be included in the message or as a MIME attachement. They should +not be compressed and/or archived unless they are very large, and if +they are very large it is probably better to store them on-line at +some place and only sent an URL. + +Write a ChangeLog entry for each change, following the format of the +existing files. Here is an example: + + 2000-12-02 Marcus Brinkmann <marcus@gnu.org> + + * ops.c (op_readlink): Before returning, check if the buffer + pointed to by transp is ours. If not, munmap it. + (op_read): Likewise for bp. + (op_readdir): Don't alloca a buffer here. Instead initialize + BUF and BUFSIZE to 0 and let the server (eh, MiG) do it. + munmap BUF before returning. + +The file name and the name of the function changed should always be +spelled out completely, and not abbreviated or otherwise mangled (like +foo.{c,h}), because that would make searching for all changes to a +file or function impossible. Local variable names are all +capitalized. There are two spaces between sentences. You can use +``C-x 4 a'' in Emacs to add a new ChangeLog entry. If you do that +with the mark being in a function, Emacs will automatically fill in +the file and function name for you. + +Do not send in a patch for the ChangeLog file. Rather include the +ChangeLog entries in the message that contains the patch. Patches for +ChangeLog files often conflict. + +If you have the original source tree in the directory `hurd-orig', and +the modified source tree in the directory `hurd', the following +command will produce a good patch (please make sure there are no extra +files like backups in the modified tree, or leave away the option +`-N'). You will need to collect the ChangeLog entries seperately. + + # diff -x ChangeLog -Nurp hurd-orig hurd + + +Answers were given by (in chronological order): +* {NHW} Neal H Walfield <neal@cs.uml.edu> +* {MB} Marcus Brinkmann <Marcus.Brinkmann@ruhr-uni-bochum.de> +* {AMS} Alfred M. Szmidt <ams@gnu.org> +* {OK} Ognyan Kulev <ogi@fmi.uni-sofia.bg> +* {FH} Frédéric Henry <neryel@reveries.info> +* {MM} Manuel Menal <mmenal@hurdfr.org> diff --git a/hurd/faq/old_hurd_faq.txt b/hurd/faq/old_hurd_faq.txt new file mode 100644 index 00000000..c7e0ffe8 --- /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 (Broken Link ?) + +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/faq/release.mdwn b/hurd/faq/release.mdwn new file mode 100644 index 00000000..d80c6825 --- /dev/null +++ b/hurd/faq/release.mdwn @@ -0,0 +1,15 @@ +[[!meta copyright="Copyright © 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="When will the Hurd be released?"]] + +Next year. + +Save that, read about the Hurd's [[status]]. diff --git a/hurd/faq/slash_usr_symlink.mdwn b/hurd/faq/slash_usr_symlink.mdwn new file mode 100644 index 00000000..5c47f4e1 --- /dev/null +++ b/hurd/faq/slash_usr_symlink.mdwn @@ -0,0 +1,20 @@ +[[!meta copyright="Copyright © 2001, 2002, 2003, 2004, 2005, 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="Why is `/usr' a symbolic link to `.'?"]] + +The distinction between `/` and `/usr` has historical reasons. Back when [[Unix]] +systems were booted from two tapes, a small root tape and a big user tape. +Today, we like to use different partitions for these two spaces. The Hurd +throws this historical garbage away. We think that we have found a more +flexible solution called union filesystems, which allow to create virtual +filesystems which are the union of several other filesystems. However, support +for union filesystems is still in early development. diff --git a/hurd/faq/smp.mdwn b/hurd/faq/smp.mdwn new file mode 100644 index 00000000..953784da --- /dev/null +++ b/hurd/faq/smp.mdwn @@ -0,0 +1,17 @@ +[[!meta copyright="Copyright © 2009 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="Does GNU/Hurd support SMP/Multicore?"]] + +The Hurd servers themselves are multithreaded, so they should be able to take benefit of the parallelism brought by SMP/Multicore boxes. This has however never been tested yet because of the following. + +Mach used to be running on SMP boxes like the [[http://en.wikipedia.org/wiki/Intel_iPSC/860 | iPSC 860]], so has an infrastructure for running on them. It has however not (yet) been ported to nowadays' SMP standards like ACPI etc. + +That is why for now GNU/Hurd will only uses one logical processor (i.e. one core or one thread, depending on the socket type). diff --git a/hurd/faq/still_useful.mdwn b/hurd/faq/still_useful.mdwn new file mode 100644 index 00000000..bffeaebd --- /dev/null +++ b/hurd/faq/still_useful.mdwn @@ -0,0 +1,46 @@ +[[!meta copyright="Copyright © 2009 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]]."]]"""]] + +what are the advantages with the Hurd over Linux, in general of course, nothing +in depth + +> Flexibility for the user: +> +> transparent ftp +> +> $ cd /ftp://ftp.debian.org/debian +> $ ls +> +> personnal filesystem +> +> $ dd < /dev/zero > myspace.img bs=1M count=1024 +> $ mke2fs myspace.img +> $ settrans myspace /hurd/ext2fs myspace.img +> $ cd myspace + +>> Just curious, but I keep seeing these (and other similar) concepts being +>> brought up as the amazing selling points of the Hurd, but all of this is +>> entirely doable now in Linux with FUSE or things like it. + +>>> Nowadays, at LAST, yes, partly. + +>> I'm not sure if an ftp filesystem has been implemented for FUSE yet, but its +>> definately doable; and loopback filesystems like in your second example have +>> been supported for years. + +>>> As a normal user? And establish a tap interface connected through ppp over +>>> ssh or whatever you could want to imagine? + +>> What, then, are the major selling points or benefits? + +>>> These were just examples, Linux is trying to catch up in ugly ways indeed +>>> (yes, have a look at the details of fuse, it's deemed to be inefficient). +>>> In the Hurd, it's that way from the _ground_ and there is no limitation +>>> like having to be root or ask for root to add magic lines, etc. diff --git a/hurd/faq/top.mdwn b/hurd/faq/top.mdwn new file mode 100644 index 00000000..9e385c0f --- /dev/null +++ b/hurd/faq/top.mdwn @@ -0,0 +1,16 @@ +[[!meta copyright="Copyright © 2009 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 a replacement for procps' top?"]] + +Here is a replacement to use, until the real `top` works, which depends on +[[hurd/translator/procfs]] and some [[!taglink porting|open_issue_porting]]. + + $ while :; do ps -e -v -s CPU --top=22 -r; sleep 5; done diff --git a/hurd/faq/which_microkernel.mdwn b/hurd/faq/which_microkernel.mdwn new file mode 100644 index 00000000..6180dbbb --- /dev/null +++ b/hurd/faq/which_microkernel.mdwn @@ -0,0 +1,19 @@ +[[!meta copyright="Copyright © 2009 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 happened to the L4/Coyotos/viengoos micro-kernels?"]] + +L4 was promising but happened to not be suitable for implementing a general-purpose operating system on top of it. See [[history/port_to_l4]]. + +Coyotos is abandoned upstream + +Neal Walfield started working on a newly designed kernel called [[viengoos|microkernel/viengoos]]. Unfortunately, he currently lacks time and the projects it paused. + +In the meanwhile, people are thus continuing with [[microkernel/mach]]. |