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diff --git a/hurd/faq/old_faq.txt b/hurd/faq/old_faq.txt deleted file mode 100644 index 617d7661..00000000 --- a/hurd/faq/old_faq.txt +++ /dev/null @@ -1,562 +0,0 @@ -[[!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> |