Technotools/Technotools (Chestnut CD-ROM)(1993).ISO/unix/linstd/linux.faq

Text File | 1992-03-10 | 43.8 KB | 1,123 lines

From netnews.upenn.edu!jvnc.net!darwin.sura.net!convex!cs.utexas.edu!usc!rpi!think.com!mintaka.lcs.mit.edu!bloom-picayune.mit.edu!daemon Tue Mar 10 17:47:33 EST 1992


Hi, sorry for the delay but my system breakdown after the posting of CDIFF

Hi Linuxers!

The originall FAQ 1st version was posted in Dec. 19, by Robert Blum,

Most credits of this work to Linus, Robert and Ted, the rest was
either on the list posted by many (real) activists, not me ;-), either
in some other news groups, or else by direct posting to me (thanks
Humberto). I haven't copyrighted them, so thanks to every one who
participated even indirectly to this FAQ.

[To find what has changed, view the `Cdiff-faq' in my previous posting.
The last-change-date of this posting is always "two minutes ago".  :-)]

This is the introduction to a list of frequently asked questions (FAQ
for short) about Linux with answers (Yeap!).  This article contains a
listing of the sections, followed by the question/answer part.

This FAQ is supposed to reduce the noise level ;-) in the alt.os.linux
newsgroup (and also the 'linux-activists' mailing list), and spare the
time of many activists. I will post it twice a month, since there are
more and more new incomers, and new features.

BTW I think this FAQ should be available at the main Linux sites in
the doc directory (have you read this  Ary, Robert, Ted ?)

Please suggest any change, rephrasing, deletions, new questions,
answers ...
Please include "FAQ" in the subject of messages sent to me about FAQ.
Please use [e-mail] whatever will be the From part
of this message.


Thanks in advance,
                                Marc <[e-mail]>

Remind the vote for comp.os.linux;
post the YES vote to [e-mail]
The voting period will last through 00:00 UTC (7:00pm EST), 19 March
1992.

Future Plan:
        - mark question/answer that have heavily changed recently
        - verification/location/organization for files available
        via FTP (I've tried what a mess!!)
        - cross posting this to news.answers as soon as comp.os.linux
        is created (may be earlier, on march)

================================8<=====8<==============================
CONTENTS
        I.      LINUX GENERAL INFORMATION
        II.     LINUX USEFUL ADRESSES
        III.    INSTALLATION and SECURITY
        IV.     LINUX and DOS
        V.      SOME CLASSICAL PROBLEMS
        VI.     INSTALLATION HINTS
        VII.    FEATURES
        VIII.   MORE HINTS

I. LINUX GENERAL INFORMATION
=============================

QUESTION: What is linux?

ANSWER: Linux is a small unix for 386-AT computers, that has the added
advantage of being free. It is still in beta-testing, but is slowly
getting useful even for somewhat real developement.  The current
version is 0.12, date: Jan. 14th 1992. The next version will come out
in the end of February, beginning of March as the Linux v0.13/0.95

   LINUX 0.12 is a freely distributable UNIX clone.  It implements a
subset of System V and POSIX functionality.  LINUX has been written
from scratch, and therefore does not contain any AT&T or MINIX
code--not in the kernel, the compiler, the utilities, or the
libraries.  For this reason it can be made available with the complete
source code via anonymous FTP.  LINUX runs only on 386/486 AT-bus
machines; porting to non-Intel architectures is likely to be
difficult, as the kernel makes extensive use of 386 memory management
and task primitives.


QUESTION: What is the current state of Linux?

ANSWER: do "finger [e-mail]", or read the
alt.os.linux newsgroup.


QUESTION: I've just heard about linux, what should I do to get it?

ANSWER: First read all this FAQ, and the INFO-SHEET monthly post, then
go to the nearest ftp site (see below), download the Images there are
two a rootimage and a bootimage (in general in the images directory),
download the INSTALL and RELNOTES files.  Find the rawrite utility
(for example at tsx-11 it's in /pub/linux/INSTALL), then rawrite the
images on high density floppies (5.25 or 3.5), finally boot on the
root diskette and that's it.


QUESTION: Does it run on my computer?

ANSWER: Linux has been written on a clone-386, with IDE drives and a
VGA screen. It should work on most similar setups. The harddisk should
be AT-standard, and the system must be ISA.  A high density floppy
drive -- either 5".25 or 3".5

Otherwise the requirements seem relatively small: a 386 (SX, DX or any
486).  Any video card of the following: Hercules, CGA, EGA, (S)VGA.

It needs at least 2M to run, and 4M is definitely a plus. It can
happily use up to 16M (and more if you change some things).  People
are working on a SCSI-driver.

BTW it works for some ESDI drive (Joincom controller with Magtron
drive after you have commented out the "unexpected hd interrupt"-message
from hd.c). And quite recently for some SCSI adapter (adaptech-1542)
by Tommy Thorn in digest19 vol#1 of alt.os.linux.


QUESTION: How would this operate in an OS/2 environment?

ANSWER: Fine.


QUESTION: Will linux run on a PC or 286-AT? If not, why?

ANSWER: Linux uses the 386 chip protected mode functions extensively,
and is a true 32-bit operating system. Thus x86 chips, x<3, will
simply not run it.


QUESTION: How big is the 'complete' Linux package?

ANSWER: Well, the boot and root image diskettes are about 750k
compressed.  The kernel sources are about 200k compressed, and the
libc sources are another 170k compressed.  The GNU C compiler is 670k,
and the other miscellaneous unix utilities are probably a bit over a
megabyte.

Now add sources to whatever you want to port and compile yourself.
The sources to GNU emacs are about 3 megabytes, compressed.  Groff (a
troff replacement) is just over 1 megabyte.

If you think this is big, remember that the OS/2 2.0 Limited
Availability release is 20 1.44 megabyte diskettes.


QUESTION: Since how long does linux exist?

ANSWER (partial): Few months, v0.10 went out in Nov. 91, v0.11 in Dec.
and the current version 0.12 is available since Jan. 14th 92. But even
it is pretty recent it is quite reliable. There are very few and small
bugs and in its current state it is mostly useful for people who are
willing to port code and write new code.


QUESTION: What's about the copywright of linux.

ANSWER: In the previous release, Linux was copyrighted by Linus
Torvalds but free. The copyright will change (v0.13 /0.95 ?) to
follows the same set of rules as the GNU copyleft.


QUESTION: Should I be a UNIX and/or a DOS wizard to install/use Linux?

ANSWER: Not at all, just follow the install rules, of course it will be
easier for you if you know things about Unix. Right now Linux is used
by more than 400 persons, very few of them enhance the kernel, some
adds/ports new soft and most of us are only (but USEFUL) beta testers.
So join us and choose your "caste"


QUESTION: What are the differences, pros and cons compared to Minix ?

ANSWER (partial):
Cons:
- Linux is not as mature as Minix, there is less working software right now.
- Linux v0.12 doesn't have real login yet, you are root all the time.
    this will change pretty soon in the next version (end Feb.). Right
    now, you can use the Peter Orbaek init/login package (see VIII.)
- Linux only works on 386 and 486 processors.
- Linux needs 2M of memory just to run, 4M to be useful.
- Linux is a more traditional unix kernel, it doesn't use message passing.

Pros:
- Linux is free, and freely distributable.
- Linux has some advanced features such as:
  - Memory paging with copy-on-write
  - Demand loading of executables
  - Page sharing of executables
  - Multi-threaded file system
  - job control and virtual memory, virtual consoles and pseudo-ttys.
- Linux is a more traditional unix kernel, it doesn't use message
passing.


QUESTION: Does Linux use TSS segments to provide multitasking?

ANSWER: Yes!


QUESTION: If my PC runs under Linux, is it possible to ftp, rlogin,
rsh etc.. to other Unix boxes?

ANSWER: Not yet, but kermit has been ported to Linux, and the ka9q too.


QUESTION: Does linux do paging? Can I have virtual memory on my small
machine?

ANSWER: Linux0.12 does do paging, but it's pretty rudimentary. It's
even more beta than the rest of linux. How it selects which page to be
thrown out of memory is particularly primitive. It is there though and
it does appear to work


QUESTION: Can I have tasks spanning the full 4GB of addressable 386
memory? No more 64kB limits like in coherent or standard minix?

ANSWER: Linux does limit the task-size, but at a much more reasonable
64MB (MEGA-byte, not kilos), so bigger programs are no problem.


QUESTION: Does the bigger program sizes mean I can run X?

ANSWER: X is not ported to linux, and I hope it will be some day,
people are working hard on it but it's big, and wants a lot from
the system.


II. LINUX USEFUL ADRESSES
=========================

QUESTION: Where can I get linux?

ANSWER: Linux can be gotten by anonymous ftp from
        nic.funet.fi (128.214.6.100):
                directory /pub/OS/Linux
        Tupac-Amaru.Informatik.RWTH-Aachen.DE (137.226.112.31):
                directory /pub/msdos/replace
        tsx-11.mit.edu (18.172.1.2):
                directory /pub/linux
        ftp.eecs.umich.edu (141.212.99.7):
                directory linux
        puffin.doc.ic.ac.uk (146.169.3.7):
                directory /pub/os/Linux
        ustsun.s.u-tokyo.ac.jp (133.11.11.11):
                directory misc/linux

You might want to check out which of these is the most up-to-date.

If you don't have ftp-capability, you are in trouble. See next Q/A.  If
you have no uncompress utility, there are a lot even for DOS, have a
look on SIMTEL, or else use facilities provided by some sites to
uncompress for you. Don't do that if you can, because it's lengthy,
expensive and causes troubles to other users on ftp sites.


QUESTION: I do not have FTP access, what can I do to get linux?

ANSWER: Try to contact a friend on the net with those access, or try
mailserver/ftpmail server otherwise contact [e-mail]. You
might try mailing "[e-mail]" with "help" in the body of
the mail.  If you choose ftpmail server (example: [e-mail]),
with "help" in the body, the server will send back instructions and
command list. As an exemple to get the list of files available at tsx-11
in /pub/linux send:

                mail [e-mail]
                subject: anything
                reply <your e-mail>
                connect tsx-11.mit.edu
                chdir /pub/linux
                dir -R
                quit

QUESTION: Is there a newsgroup or mailing-list about linux? Where can
I get my questions answered? How about bug-reports?

ANSWER: alt.os.linux is formed, and comp.os.linux is on the way, for
those who can't access to the news you can ask for digest to:
[e-mail]. On the other hand, mail
sent to [e-mail] are posted to
alt.os.linux

DO NOT mail "I want to [un]subscribe" to the newsgroup, use
the request-address. IF not your mail-box will be over-crowded by
activists.

Questions and bug-reports can be sent either to the newsgroup or to
"[e-mail]", depending on which you find more
appropriate.

BTW People are working on the organization of Linux, this is done on
a separate mailing-list.

linux-standards: Discussion of distribution and directory standards
for the Linux operating system, including directory structure, file
location, and release disk format.

Requests to be added to this list must be sent to:
              [e-mail]

QUESTION: Does there exist a place where the traffic of the newsgroup
is kept?

ANSWER: Yes, on nic and tsx-11 (see the ftp adresses above)

III. INSTALLATION and SECURITY
==============================

QUESTION: How can I be sure I won't be writing over anything
important?  I have to use DOS on my machine, and I don't want to
lose any files.

ANSWER: Back up everything. Just in case. Then, write some easily
recognizable pattern to the partition you have reserved for linux,
using some DOS tool. You can then use "cat /dev/hdX" under linux to
examine which of the partitions you used.


QUESTION: Linux mkfs doesn't accept the size I give the device,
although I double-checked with fdisk, and it's correct.

ANSWER: Be sure you give the size in BLOCKS, ie 1024 bytes, not
sectors. The mkfs doesn't work for very big partition (over than 64
Megs). Also, make doubly certain that you have the correct partition.

There are a few rules about this: /dev/hd0 and /dev/hd5 are always the
same under linux and minix.  DO NOT USE THEM, they are the whole raw
disk, not partitions. Also if a partition is on drive 1 under minix
(ie /dev/hd1-4), it is drive 1 under linux as well.  Moreover, there
is no real consensus on whether partition #1 is the first partition on
the disk, or is the first entry in the partition table.  Some parition
programs sort this information on the screen only, some will write the
sorted information back to the hard disk.  Linux assumes that the
first entry is hd1, and so if some utility starts sorting/reordering
the table these things can change.  Moreover, do not use extended
partition (this is in the installation notes).

REMARK Minix does some reordering.

A useful hack is to make each of your partitions a different size.
Then after any editting or possible change to the partition table you
can boot a floppy system and run fdisk (linux's, not DOS) to see if
the assignments still hold.


QUESTION: I have a one partitionned 40Mb disk. If I run mkfs, what
happens?

ANSWER: If you do that, you will have an empty 40Mb Linux file system
(currently the same fs as Minix). You should, at least, make on your
hard disk, one partition per operating system you want to use.


QUESTION: I mounted the linux filesystem, and copied the files from
the root-disk to the harddisk. Now I cannot find them any more, and
somethimes linux dies with a "panic: trying to free unused inode".

ANSWER: You have probably forgot to sync before rebooting. Linux, like
all unices, use a "buffer cache" to speed up reads and writes to disk.
On a machine that has enough memory, this buffer-cache is 1.5MB, and
if you forget to sync before exiting, it may not be fully written out
to disk. Re-mkfs and re-install (or try to use the preliminary fsck,
but remember that although fsck tries to correct the faults it finds,
it may fail.)


IV. LINUX and DOS
=================

QUESTION: Is it possible to access to DOS world from Linux

ANSWER: Yes, there is the mtools package (with patches for devices.c)
The original sources of mtools can be found at any places not only at
nic, tupac and tsx-11, and the patches for Linux (with fix for big DOS
partitions are in the directory patches or ports). Moreover you should
download the file patch.Z to apply patches :)

QUESTION: the mtools package won't work. I get an ENOENT error message
for all devices.

ANSWER: mtools needs to be told which device to look for. Use 'ln' or
'mknod' to create a special file called "/dev/dosX", where X is A, B,
C, X or Y. A and B are for floppies (12 bits), C is for hard disk and
X, Y for any. This file should point to the device you want to read.
About the minor/major pair have a look in section INSTALLATION HINTS.


QUESTION: What is as86.tar.Z ?

ANSWER: It's the port of Bruce Evans' minix assembler, you need it to
be able to recompile Linux at your convenience.


QUESTION: Turbo (Microsoft) Assembler won't compile the Linux boot
code.  In fact, some of the opcodes in these files look completely
unfamiliar.  Why?

ANSWER: The Linux boot codes are written in Bruce Evans' minix
assembler, which has the same opcodes as the original minix assembler
ported to linux get as86.tar.Z Anyway there are a few differences
between these and normal DOS assemblers:

 - No segments - everything is in the same segment (at least in the
   bootsectors and setup, as they don't use the .data segments)

 - mov[b|w|l] are shorter versions of mov ax,[byte|word|long] ptr
[XXX].
   This is how unix assemblers normally give the size (byte, word or
long).
   Gas has similar constructs.

 - There is no "jmp short", the opcodes are "j" for a short jump and
   "jmp" for a long one.

 - "jmpi" is a jump with a segment:offset pair. I don't know how this
is
   written in DOS assembly.


V. SOME CLASSICAL PROBLEMS
==========================

QUESTION: While running du I get "Kernel panic: free_inode: bit
already cleared".  Also, du produces a ENOENT error for all the files
in certain of my directories.  What's going on?

ANSWER: These are both consistent with a bad file-system.  That's
relatively easy to produce by not syncing before rebooting, as linux
usually has 1.5MB of buffer space held in memory (unless you have <=4M
RAM, in which case the buffers are only about 0.5MB). Also linux
doesn't do anything special about the bit-map blocks, and as they are
used often, those are the thing most likely to be in memory. If you
reboot, and they haven't been written to disk ...

Just do an fsck on the device, the -a flag might repair it otherwise,
the only thing to do is to reinstall the filesystem from the Images.

A sync is done only every 30 seconds normally (standard unix
practice), so do one by hand (some people think you should do 3 syncs
after each other, but that's superstition), or by logging out from the
startup-shell, which automatically syncs the system. Unmounting a
filesystem also syncs it (but of course you can never unmount root).

Another (sad) possibility is that you have bad blocks on your disk.
Not very probable, as they would have to be in the inode-tables, just
a couple of blocks in size. Again there aren't programs available to
read a disk for bad sectors and put them in some kind of
"bad-sector-file".  On IDE drives this is no problem (bad sectors are
automatically mapped away).


QUESTION: How can I partition my hard-drive to use Linux?

ANSWER: There are (at least) two ways to answer this. The easy way is
probably to use a program which will do it for you, such as the MS-DOS
fdisk, Minix fdisk, Xenix/Unix fdisk, or programs such as edpart.exe
or part.exe.

On the other hand, you can use a disk editor and modify the contents
of the partition table directly. This has been already done, and an
extensive explanatory note can be found in the mailing-list archives
(25th Jan. 92).

BTW It might be useful to set three (3) separated partitions for
Linux, one for the root, another one for the usr and a third one for
swap, as an illustration, my root partition is 10Meg, the usr is 40Meg
and the swap partition is 8Meg (twice the size of RAM on my box). As
an experience I have used MS-DOS fdisk to partition my two hd and got
no peculiar difficulties.

QUESTION: What must I do to mkfs a floppy?

ANSWER: blocks are of size 1K so 1.44 floppy is 1440 blocks. The
floppy has to be formatted before this will work.


QUESTION: When I run kermit under Linux, I get "Warning, Read access
to lock directory denied". What am I doing wrong?

ANSWER: Nothing, you just need to create /usr/spool/uucp, which is
where kermit like to lock files.


QUESTION: du seems buggy when i used it the number of disk occupation
is wrong.

ANSWER: Take care, if you want size in kbytes use the -k flags.


QUESTION: du works just fine on directories, except on / and /dev,
moreover "ls -l" returns either big or negative number on /dev. Why?

ANSWER: This is a "feature" added in Linux 0.12; it was originally
present in Minix; more specifically, when you stat a device file
belong to a block device, it will return the maximum size of the block
device in the st_size member of the stat structure. If you don't like
it, it's very simple to patch it out. Look in the fs/inode.c, in the
subroutine read_inode().


QUESTION: When I try to (un)compress many files in one command, the
command partially fails?

ANSWER: This is a bug, many partial fixes are floating around but ..
You can solve it by a bash command "for i in whateverfiles;do
compress $i; done"


VI. INSTALLATION HINTS
======================

QUESTION: Where can I find the basic starting help?

ANSWER: You have to download the INSTALL notes, and more specially
the 0.11 and 0.12


QUESTION: I've got all the things on site ??? but I don't know what
goes where.

ANSWER: include.tar.Z goes to /usr/include;  system.tar.Z contains
the latest sources of the
system files (mkswap, mkfs, fsck and fdisk). In version 0.12
utilbin.tar.Z has been replaced by fileutil.tar.Z and utils.tar.Z
which contains a new tar to handle the symbolic links, make, uemacs
kermit and minor programs (sed,...).  Other utilities have been ported
separately.


QUESTION: I don't know how to install gcc stuff, is there special places?

ANSWER: It depends on the release of gcc you are using. Right now
there are two packages : the original one gccbin.tar.Z contains all
the gcc-1.37 binary distrib; and quite recently there is a
newgcc.tar.Z which contains the gcc-1.40 stuff. Choose yours

A) gccbin.tar.Z goes in /usr/local/lib except gcc which goes in
/usr/local/bin. Moreover each gcc-xxx of /usr/local/lib should be
linked with gxxx and xxx in /usr/local/bin.

B) newgcc.tar.Z goes in /usr, then uncompress and untar it. Files are
directed to /usr/lib, /usr/include and /usr/bin. You have to link ar,
as, ld with gar, gas and gld, this will prevent some error while using
make (especially whilst re-compiling Linux kernel). More information can
be found in section VIII.

QUESTION: When I use the images, and i type "tar xvf ..." I got
"command not found". What did I wrong?

ANSWER: Nothing, in the distribution the tar is in compressed form
(lack of place). You have first to copy tar.Z on another disk/diskette
and uncompress it, this command is available on your diskettes.


QUESTION: What is the "em" binary?

ANSWER: Em is micro-EMacs (probably version 3.10).


QUESTION: It seems that $#@! ported on linux don't run correctly

ANSWER: Possible, but check first if the size of your file corresponds
to the one on the ftp sites, if it is then do a complete report of the
error, try to correct it.


QUESTION: Does anyone port this to linux?, if not i'll compile it

ANSWER: First check on the sites, have a look to the info-sheet
monthly post and also available on sites. Have a look in the "old"
digest files and mail-archives of linux-activists, these are kept at
least at tsx-11 and nic possibly at tupac. Look also at the GNU(*)
utilities to see if someone has already written a freely distribuable
version. Ask then on the list/news.


(*) GNU stands for GNU's Not Unix, which (besides being a recursive
acronym) is a project started by the Free Software Foundation (the FSF)
to write a freely distributable version of Unix.  The GNU kernel is
named HURD, and is based on Mach.  It is currently being written, and is
not yet done.  Many of the GNU utilities, however, are completed and are
much more functional than the original Unix utilities.  Since they are
freely available, Linux is using them as well.


QUESTION: I've ported *** to Linux, what should i do to add it in the
standard distribution?

ANSWER: Read first the previous Q/A, then to make something available to
others you have to post it (with cdiffs of the source, a short README if
needed) in the incoming directory of one of nic,tupac,tsx-11, then drop
a short note to the list/group and to the site advisor.
On nic    it's [e-mail] (Ari Lemmke)
On tupac  it's [e-mail] (Robert Blum)
On tsx-11 it's [e-mail] (Ted Ts'o)


QUESTION: I want to port *** to Linux, what are the flags?

ANSWER: Recall that Linux implements subset of SYSV and POSIX, so
-DUSG and -DPOSIX work in general. Moreover throw away most of the ld
flags such as -ltermcap, -lg, since the libg.a and libtermcap.a are
missing.


QUESTION: Linux lacks on ****/ Linux has a bug in ***, what are the
rules to enhance/correct the kernel?

ANSWER: Before anything check if some one else is working on that
subject, contact those people. Test your improvment (it should work is
NOT enough), then send the patches in cdiffs form to Linus and/or the
list, moreover the localization must be clear. This does NOT mean that
bug-reports and patches are not accepted.


QUESTION: I seem to be unable to compile anything with gcc. Why?

ANSWER: If you have only 2 MB RAM, gcc will die silently without
compiling anything. You must have at least 4 MB to do compilations

BTW Since swapping is possible, I have heard that compilation is
possible with only 2Meg and a lot disk traffic :) Isn't it great?

QUESTION: I'm using a program that uses signal handlers which are
installed using sigaction() with the SA_NOMASK, and they get a general
protection error right after the signal handler tries to return.
What's going wrong?

ANSWER: You are using a libc.a that has an out-of-date signal.o and
sig_restore.o file, and they don't know how to deal with SA_NOMASK.
(The one in gccbin.tar.Z is out-of-date). Get the new libc.a and put
it in /usr/lib or /usr/local/lib


QUESTION: gcc complains about not finding crt0.o and the system
include files What am I doing wrong ?

ANSWER: The include files normal place is in /usr/include. lib*.a and
*.o should be in /usr/lib or /usr/local/lib


QUESTION: While compiling some GNU packages gcc chokes on regex.c with
an insn code, what can I do?

ANSWER: There is a little bug in the port of gcc-1.37, this will be
corrected on the port of v2.0 (with g++). Right now throw away the -O
flag (to compile regex) and every thing will be alright.

BTW there are some minor bugs with this release of gcc because it was
compiled under linux-0.10, whith odd libraries. These problems have
disappeared with the new gcc-1.40 package.

QUESTION: I tried to port a /new/ version of gnu stuff. But in the
linking phase, gcc complains about the missing libg.a.

ANSWER: Yes this is well known, throw away the flag -g that's all,
anyway libg.a is /only/ for debugging purpose.


QUESTION: I can't move directories under Linux, why ?, what can I do?

ANSWER: mvdir needs kernel resources which don't exist yet.  The
reason the rename system call isn't implemented yet is that there are
a couple of problems with it: it isn't as straightforward as you'd
imagine. Race conditions, inclusion checking etc..

It will befinitely be in 0.13/0.95. It's not /that/ difficult, just
needs a little thought. In the meantime, you might fake it with "cp
+recursive" and "rm -rf". Be careful with that though..
You can also write a bash script, which simulates the mvdir (really a
good exercice :) )

This also appears to be the reason why mv's of sym links do not work
properly.

BTW Linus has already done it for linux v0.12 it's a patch available
in the digest10 vol #1 of alt.os.linux.

QUESTION: What are the device minor/major numbers?

ANSWER: (early Linus mail Nov. 6th 91, last update Jan. 19th 92)
                Memory devices: Major = 1 (characted devices) minor
0       /dev/ram
1       /dev/mem
2       /dev/kmem - not implemented (easy, but I haven't done it)
3       /dev/null
4       /dev/port (implemented, but untested - don't play with it)

example: "mknod /dev/null c 1 3"


                Floppy disks: Major = 2 (block devices)

minor = drive + 4*type, drive = 0,1,2,3 for A,B,C or D-diskette

type    1: 360kB floppy in 360kB drive (5.25")
        2: 1.2M floppy in 1.2M drive (5.25")
        3: 360kB floppy in 720kB/1.44Mb drive (3.5")
        4: 720kB floppy in 720kB/1.44Mb drive (3.5")
        5: 360kB floppy in 1.2M drive (5.25")
        6: 720kB floppy in 1.2M drive (5.25")
        7: 1.44M floppy in 1.44M drive (3.5")

Thus minor nr for a 1.44Mb floppy in B is: 1 + 4*7 = 29, and to read
an old 360kB floppy in a 1.2M A-drive you need to use minor= 0 + 4*5
= 20.

Example: "mknod /dev/PS0 b 2 28" (b for block: 2 for floppy, 28 for
1.44 in A)


                Hard disks: Major = 3 (block devices) minor
0       /dev/hd0 - The whole hd0, including partition table sectors
etc.
1       /dev/hd1 - first partition on hd0
...
4       /dev/hd4 - fourth partition on hd0
5       /dev/hd5 - The whole hd1, again including partition table info
6       /dev/hd6 - first partition on hd1
...
9       /dev/hd9 - fourth partition on hd1

NOTE! Be /very/ careful with /dev/hd0 and /dev/hd5 - you seldom need
them, and if you write to them you can destroy the partition tables:
something you probably don't want.  The only things that use /dev/hd0
are things like "fdisk" etc.

NOTE 2!! The names for hd's are the same as under minix, but I think
minix orders the partitions in some way (so that the partition numbers
will be in the same order as the partitions are physically on the
disk).  Linux doesn't order anything: it has the partitions in the
same order as in the partition table (ie /dev/hd1 might be physically
after /dev/hd2).

                        Tty's: Major = 4 (character devices) minor
0       /dev/tty0       - general console 1 -
63                      - reserved for virtual console
64-127                  - reserved for serial io
128-                    - reserved for pty's

And more particularly we have:
64      /dev/tty64      - com1
65      /dev/tty65      - com2


QUESTION: How to start Linux from drive B?

ANSWER: There is a DOS utility called boot_b.exe (look at DOS ftp).
Another simple way is to open the box and invert the cables.

QUESTION: The program boot_b works fine /but/ once the first disk is
read the system go back to the first drive, any hints?

ANSWER: Yes, change the bootimage in just the same way that you change
it to boot on the hard drive, execept that the major/minor pair is
different. All these information are in the file INSTALL-0.10.
Remember that if you use a sun or other endian machine, you will need
to reverse the byte order when you run the filter program (also in the
same file).


VII. FEATURES

=============

QUESTION: I've read that linux has virtual consoles, what must I do to
get them?

ANSWER: Yes there are, you can access them with the left <alt>-key
together with <Fn>-key. But first you have to activate them with doshell
/dev/ttyn /bin/sh & where n is the number of the Virtual console.
With the Linux 0.12 Images distribution, two consoles are available,
but if you want to use the second do first:
                     "doshell /dev/tty2 /bin/sh&"
Moreover if you want to activate automatically the Virtual console,
you should add this command in the /etc/rc file.

BTW: the serial ports are now /dev/tty64 and /dev/tty65. tty0 is the
general console. tty128- are reserved to pty's


QUESTION: What kind of shell is /bin/sh ?

ANSWER: It's the Bourne Again Shell, bash-1.11 and compilation was
straightforward (Linus dixit), just "make" that's all or nearly.


QUESTION: Does there exist a man page for **** ?

ANSWER: Download man.tar.Z from your favorite linux ftp site, there is
most of the fileutils man page -- either **** or g****, example there
is nothing on ld, but there is for gld :) --, check the whatis
database provided. The files in the cat1 dir are pre-formatted man
pages that the man program can use.

BTW there is no roff,troff nor nroff for Linux. Cawf 2.0 works just
fine for simple man pages, and a partial ms support too.


QUESTION: What are the editors available in linux?

ANSWER: Right now there are uemacs, elvis-1.4, some one (R. Blum)
is working on some other vi clone. The port of emacs 18.57 has been
done by John T Kohl, files can be found at the different sites
at nic          it's in the directory xtra
at tsx-11       it's in the directory ports/emacs-18.57.
Also the port of mg (micro gnu) has been done and can be found at
least at athos.rutgers.edu (128.6.4.4) in pub/linux, mg is the binary
and mg.tar.Z is the sources file.

QUESTION: Does there exist a printer package for Linux?

ANSWER: There are lp patches for linux.0.12, which implement a
parallel printer interface and feature a greatly improved driver
design. the patches are in lp.12.tar.Z As I have no printer (yet), I
don't know how good it is.


QUESTION: Does there exist a ps for Linux?

ANSWER: Yes in the vc2.tar.Z file, however the command is very kludgy.

QUESTION: It's nice to have the df utility, but it would be nicer if
it would give statistics of the root file system. Would it be
difficult to do?

ANSWER: surely not, in your file /etc/rc, instead of the line
                        > etc/mtab
put the following
                        echo "/dev/hdX (root)" > /etc/mtab
where the X is the hard drive you use as root partition.


QUESTION: How do I make swapping work?, when I boot I get the
following message: "Unable to get size of swap device"

ANSWER: There are two ways (as far as I know). Recompile the kernel
and makes the swap device available (have a look in the main
Makefile). Or else you can modify the bootimage, in that case you have
to put a full device number in the word reserved for the swap device:
the logic is the same as for the root device. Thus, if you want
/dev/hd2 to be your swap-device, you'll have to write a 2 (minor nr)
into byte 506, and a 3 (= harddisk) into byte 507. You can use
virtually the same program as for the root-device (look in INSTALL
files).


QUESTION: When I boot I get one of the following messages:
"Unable to find swap signature" or "Bad swap-space bitmap"

ANSWER: You probably forgot to make your swap-device, use the mkswap
command.


QUESTION: How do I know if it is swapping?

ANSWER: You will notice it :)) First of all, Linux tells you at boot
time, "Adding swap: XXX pages of swap space", and if you start running
out of memory, you will notice that the disk will work overtime, and
things slow down. Generally a 2Meg RAM will make the system swap
constantly while running gcc, 4 Meg will swap occasionnaly when
optimizing big files (and having other things active, such as make).


QUESTION: Is there only the %$#@ keyboard ?

ANSWER: There are Finnish, French, German,and US keyboards. Set it in
linux/kernel/chr_drv/keyboard.S, then  compile the kernel again.

BTW a Dannish keyboard patch (Tommy Thorn) is now available look the
digest19 vol#1 file. There is an Uk keyboard too (Jan 25. by Leblanc),
I have not seen it in the newsgroup so ask directly to
[e-mail]


QUESTION: Does there exist shared libs ?

ANSWER: They seem to work. The kernel features are in Linux 0.12
already.


QUESTION: Does Linux permit/support bitmapped graphics on vga/svga
cards?

ANSWER: No, there is no interface for graphics operations on Linux
(yet).

QUESTION: There are a lot of patches available (fd patch, lp patch
login patch ...) can I be fairly confident the subsequent patches will
work?

ANSWER: No you can't, patching is a real beta tester art :)). People
are not working on the same patched release, so you have to check if
the patches you already applied works on the same kernel part, if not,
/great/, just apply them. If yes, check if there is an order, patch
creator knows that, and (should) try to warn patch user (in other
words: beta tester) otherwise you should edit the patch files (and
possibly make a brief note to others on this list/newsgroup or even
a cdiff) before applying them, another solution is to keep cool and
wait for the next version of Linux where, in general, the
modifications have been done but this behavior is /not/ Linux
helpful.


QUESTION: I got the patches on some ftp sites, and applied them to the
kernel and tried to compile. It didn't !!. Are the patches buggy?

ANSWER: Before remake, just do a make clean in the directories
involved by the patches. This will force a rebuild of the .o and .a
files.
If you have a RCS running on your source tree, did you checked a
patched version of the files changed before /any/ CO either by you or
make

VIII. MORE HINTS
================
This part is quite recent and try to keep track of the different
information that appeared in alt.os.linux and on the list since
beginning of February. I have not checked all of these information.
But the one I know correct are marked by a (+). Fill free to contact
me and infirm/confirm what is written below. Moreover take care to use
the correct library and include stuff for linux-0.12 and the ad-hoc
gcc you use !!!


QUESTION: How can I backup my Hd under Linux ?

ANSWER: I know at least two ways. One possibility is tar and mtools,
another possibility is the diskbackup/diskrestore of Diamano Bolla
(digest44 vol. #1) which saves big hd to floppies using the
stdin/stdout.


QUESTION: How to use setterm: for the novice?

(+)ANSWER:The setterm utility provides access to most of Virtual Consoles
(VCs) functionality.  You can set your screen up to blank at 10
minutes using:
                setterm -blank 10

You can set colors, and clear the screen.  For a full list of commands,
just type "setterm" with no arguments.

There are a few tricks with the screen dumper can really make VCs go a
long way.  Here are a few of the common ones that I use:

                setterm dump

Dumps the contents of the current VC to screen.dump (in the current dir).

                setterm dump 4

Dumps the contents of VC 4 to screen.dump

                setterm -file mydumpfile -dump 4

Dump the contents of VC 4 to the file mydumpfile

                setterm -file /dev/tty0 -dump 4

Dumps the contents of VC 4 to the current VC.

                setterm -file /dev/tty4 -dump

Dumps the contents of the current VC to VC 4.

                setterm -file /dev/tty64 -dump

Dumps the contents of the current VC to the serial port.
Handy if you are logged on and want to paste a screen full without
having to resort to doing a file transfer.

                setterm -file mydumpfile -append 4

Appends to instead of overwriting the dump file.  Useful if you
have several screens you wish to concatenate.


QUESTION: I know there are VC, but where is the setterm stuff?

(+)ANSWER: It is in virtcons.tar.Z (at least on nic). It provides a
number of features that are not available with the standard release of
linux-0.12, among them blanking/dumping screen.


QUESTION: While using emacs in 80x25 mode, the mode line is constantly
moving around, why?

ANSWER: This appear to be a bug in the scroll region handling of the
console. Some one has suggested to simply remove the last entry in the
vt100 termcap that refers to the scroll region escape. Namely remove
the cs entry.


QUESTION: I have read that there are patches for an init/login in
Linux-0.12, where can I find them.

(+)ANSWER: There are many, one is the qpl-init.tar.Z package available
at the 3 main sites, but it is not that good (it's a quick hack).
There is also the Peter Orbaek init/login stuff that can be down-load
from ftp.daimi.aau.dk (130.225.16.1); the last version is in the file
poeigl-1.1.tar.Z and it is in pub/Linux-source. Among other things it
contains a patch to main.c of Linux kernel v0.12 (directory init). You
have to recompile the kernel (after patching it) to use /etc/init
rather than /etc/rc at boot time.


QUESTION: How can I change user password in login?

(+)ANSWER: There is no passwd program yet, you should do it by hand
with the encrypt stuff provided.


QUESTION: When I use make as non root, it doesn't work, why?

(+)ANSWER: ?????, the message is either (null) setuid ..., or (null)
setgid... I don't know how to fix it.
BTW This problem does not exist with the pmake (make for BSD 4.3 Reno
and BSD 4.4) package.


QUESTION: How can I get Linux to boot directly from the harddisk?

ANSWER: Right now, this can be done via the shoelace stuff or the
bootany package.


QUESTION: Sometimes, when I want to remove a directory, I get an error
message, is it a (known) bug?

(+)ANSWER: No, There is no bug at all, you probaly have another shell
on another VC whose working directory is either the one you try to
remove, either a subdirectory of it.


QUESTION: can anyone give me a sample /etc/inittab entry for login
from a pc attached to serial line /dev/tty65?

ANSWER: "Humberto speaking :)"
I've got a Hayes Smartmodem 1200 hooked up to /dev/tty65, and log
in daily from work. My inittab entry is

            tty65:console:/bin/agetty -m -t 30 1200 tty65

but it works without the -t OK too. The real problem I suspect you're
having is initializing the modem properly. Before setting up logins, you
have to disable echo and enable auto-answer on the modem. I do this here
by firing up kermit at 1200, connecting, then sending 'ate0s0=5'
followed by enter to the modem.


QUESTION: When compiling some code, cc1 complains about some insn
code, what's that?

(+)ANSWER: An insn is an internal representation that gcc uses when
compiling. The main part of gcc is to take ordinary c (or c++) code,
and compile it, while ding optimizations in insn part, which is
soft/hard independant. Then another part which is hard/Os dependant
takes the insns and translate it in assembly language. The fix is only
to turn off the optimization flag (-O) or download the new gcc release
(1.4) which has been made available at tsx-11 (newgcc.tar.Z and the
ad-hoc libraries newlibc.tar.Z).

BTW I've checked tsx-11 on Sat. 22nd Feb. and nothing is available,
but you can find one in /incoming at ftp.eecs.umich.edu.

QUESTION: While compiling some stuff, I'm getting the following
error message:
Undefined symbol ___addsf3 referenced from text segment
as well as ___mulsf3 and __cmpsf2.
These symbols are not in the program or in it's header files.

ANSWER: These are math helper functions, and you can usually compile
these programs to use the kernel floating point routines by adding
'-m80387' to the compiler switches. If the program does any wierd
fp math (exp(), sin()) it'll die when you run it though.


QUESTION: What are the enhancement of the newgcc.tar.Z ?

(+)ANSWER: There were some bugs in the old port that have been corrected,
moreover this package contains 387 support
there is libm.a (for those with 387)
         libsoft.a (for those without, I for example)
         libtermcap.a (from tput 1.10)

The -mstring-insns option is no longer needed nor supported :( [As
an example to recompile (successfully) linux you have to throw away
this flag in all the Makefile]

BTW Notice also that include files have changed (stdio.h which is no
more ansi compliant). Right now (Feb. 24th), there are some little
bugs which will be fixed in a short while.
The port of gcc 2.0 has begun ...


QUESTION: I've been trying to get Linux to run on my [3/4]86 box. It
can't even boot. Any suggestions?

(+)ANSWER: The most common error/problem is writing the bootimage to a
low density disk. It fits, but the bootstrap code will only recognize
high density disk. So try to format explicitely disk as high density:
- for 3.5",  'format a: /n:18 /t:80 '
- for 5.25", 'format a: /n:15 /t:80 '

QUESTION: Does there exist games, languages (other than C), and
anything which make the system more friendly?

ANSWER: Yes, among other things there are rogue and yatzee; TeX;
Prolog.. but in general, if you want some extra tool port it to Linux
this is also a good beta-testing exercice.

           ===================8<==========>8================


[/home1/c/colin/News] >