Linux-Misc Digest #555, Volume #18 Sun, 10 Jan 99 16:13:11 EST
Contents:
Linux Frequently Asked Questions with Answers (Part 5 of 6) ([EMAIL PROTECTED])
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Crossposted-To: news.answers,comp.answers
Subject: Linux Frequently Asked Questions with Answers (Part 5 of 6)
From: [EMAIL PROTECTED]
Date: Sun, 10 Jan 1999 21:12:35 GMT
Linux has two different formats for executables, object files, and
object code libraries, known as, "ELF." (The old format is called
`a.out'.) They have advantages, including better support for shared
libraries and dynamic linking.
Both a.out and ELF binaries can coexist on a system. However, they use
different shared C libraries, both of which have to be installed.
If you want to find out whether your system can run ELF binaries, look
in /lib for a file named, "libc.so.5." If it's there, you probably
have ELF libraries. If you want to know whether your installation
actually is ELF you can pick a representative program, like ls, and
run file on it:
-chiark:~> file /bin/ls
/bin/ls: Linux/i386 impure executable (OMAGIC) - stripped
valour:~> file /bin/ls
/bin/ls: ELF 32-bit LSB executable, Intel 80386, version 1, stripped
There is a patch to get 1.2.x to compile using the ELF compilers, and
produce ELF core dumps, at tsx-11.mit.edu in /pub/packages/GCC/. You
do not need the patch merely to run ELF binaries. 1.3.x and later do
not need the patch at all.
8.3 What is a .gz file ? And a .tgz ? And ... ?
.gz (and .z) files are compressed using GNU gzip. You need to use
gunzip (which is a symlink to the gzip command which comes with most
Linux installations) to unpack the file.
.taz, .tar.Z, and .tz are tar files (made with tar) compressed using
compress.
.tgz (or .tpz) is a tar file compressed with gzip.
.lsm is a Linux Software Map entry, in the form of a short text file.
Details about the LSM and the LSM itself are available in the docs
subdirectory on sunsite.unc.edu.
.deb is a Debian Binary Package - the binary package format used by
the Debian GNU/Linux distribution. It is manipulated using dpkg and
dpkg-deb (available on Debian systems and from ftp.debian.org).
.rpm is a Red Hat RPM package, which is used in the Red Hat
distribution. They can be found on ftp.redhat.com.
.bz2 is a file compressed by the more recent bzip program.
The "file" command can often tell you what a file is.
If you find that gzip complains when you try to uncompress a gzip'ed
file you probably downloaded it in ASCII mode by mistake. You must
download most things in binary mode--remember to type binary as a
command in FTP before using, "get," to get the file.
8.4 What does VFS stand for?
Virtual File System. It's the abstraction layer between the user and
real file systems like ext2, Minix and MS-DOS. Among other things, its
job is to flush the read buffer when it detects a disk change on the
floppy disk drive.
VFS: Disk change detected on device 2/0
8.5 What is a BogoMip?
"BogoMips" is a contraction of "Bogus MIPS." MIPS stands for
(depending who you listen to) Millions of Instructions per Second, or
Meaningless Indication of Processor Speed.
The number printed at boot time is the result of a kernel timing
calibration, used for very short delay loops by some device drivers.
As a very rough guide, the BogoMips rating for your machine will be
approximately:
386SX clock * 0.14
386DX clock * 0.18
486Cyrix/IBM clock * 0.33
486SX/DX/DX2 clock * 0.50
586 clock * 0.39
If the number is wildly lower, you may have the Turbo button or CPU
speed set incorrectly, or have some kind of caching problem (as
described in "When I add more memory, the system slows to a
crawl..")
For values people have seen with other, rarer, chips, see the BogoMips
Mini-HOWTO, on sunsite.unc.edu in
/pub/Linux/docs/howto/mini/BogoMips/.
8.6 What is the Linux Journal and where can I get it?
The Linux Journal is a monthly magazine (printed on paper) that is
available on news stands and via subscription worldwide. Email
[EMAIL PROTECTED] for details. Their URL is http://www.ssc.com/.
8.7 What online/free periodicals exist for Linux?
There are a number of recent additions to the list of periodicals
devoted to Linux.
* Linux Gazette. http://www.linuxgazette.com.
* Linux Weekly News. http://www.lwn.net.
* Slashdot. http://www.slashdot.org.
* Freshmeat. http://www.freshmeat.org.
[Jim Dennis, Robert Kiesling]
8.8 How many people use Linux?
Linux is freely available, and no one is required to register with any
central authority, so it is difficult to know. Several businesses
survive solely on selling and supporting Linux. Linux news groups are
some of the most heavily read on Usenet. Accurate numbers are hard to
come by, but the number is likely in the millions.
However, people can register as Linux users at the Linux Counter
project, which has been in existence since 1993. In August, 1998, the
project counted more than 70,000 users.
Visit the Web site at http://counter.li.org and fill in the
registration form. If you don't want to use the Web, send e-mail to
[EMAIL PROTECTED] with the subject line, "I use LInux at home,"
or "I use LInux at work."
The current count is posted monthly to comp.os.linux.misc, and is
always available from the Web site.
[Harald Tveit Alvestrand]
8.9 How should I pronounce Linux?
This is a matter of religious debate, of course!
If you want to hear Linus himself say how he pronounces it, download
english.au or swedish.au from ftp.funet.fi (in
/pub/Linux/PEOPLE/Linus/SillySounds/). If you have a sound card or the
PC-speaker audio driver you can hear them by typing
cat english.au >/dev/audio
The difference isn't in the pronunciation of Linux but in the language
Linus uses to say, "hello."
For the benefit of those who don't have the equipment or inclination:
Linus pronounces Linux approximately as Leenus, where the "ee" is
pronounced as in "feet," but rather shorter, and the "u" is like a
much shorter version of the French "eu" sound in "peur"
(pronouncing it as the "u" in "put" is probably passable).
9. Frequently encountered error messages.
9.1 Modprobe can't locate module, "XXX," and similar messages.
These types of messages mostly occur at boot time or shutdown. If
modprobe, insmod, or rmmod complain about not being able to find a
module, add the following to the /etc/modules.conf or
/etc/modutils/aliases file, whichever is present on your system.
alias <module-name> off
And use the name of the module that appears in the error message.
[J.H.M. Dassen]
9.2 Unknown terminal type linux and similar.
In early kernels the default console terminal type has changed from
"console" to "linux." You must edit /etc/termcap to change the
line reading:
console|con80x25:\
to
linux|console|con80x25:\
(there may be an additional dumb in there--if so it should be
removed.)
To get the editor to work you may need say
TERM=console
(for bash and ksh), or
setenv TERM console
for csh or tcsh.
Some programs use /usr/lib/terminfo instead of /etc/termcap. For these
programs you should upgrade your terminfo, which is part of ncurses.
9.3 lp1 on fire
This is a joke/traditional error message indicating that some sort of
error is being reported by your printer, but that the error status
isn't a valid one. It may be that you have some kind of I/O or IRQ
conflict-- check your cards' settings. Some people report that they
get this message when their printer is switched off. Hopefully it
isn't really on fire ...
In newer kernels, this message reads, "lp1 reported invalid error
status (on fire, eh?)"
9.4 INET: Warning: old style ioctl... called!
You are trying to use the old network configuration utilities. The new
ones can be found on ftp.linux.org.uk in
/pub/linux/Networking/PROGRAMS/NetTools/ (source only, I'm afraid).
Note that they cannot be used just like the old-style programs. See
the NET-2 HOWTO for instructions on how to set up the old-style
networking programs correctly. Even better, see the NET-3 HOWTO and
upgrade your networking software.
9.5 ld: unrecognized option '-m486'
You have an old version of ld. Install a newer binutils package--this
will contain an updated ld. Look on tsx-11.mit.edu in
/pub/linux/packages/GCC/ for binutils-2.6.0.2.bin.tar.gz.
9.6 GCC says Internal compiler error.
If the fault is repeatable (i.e., it always happens at the same place
in the same file--even after rebooting and trying again, using a
stable kernel) you have discovered a bug in GCC. See the GCC Info
documentation (type Control-h i in Emacs, and select GCC from the
menu) for details on how to report the error--make sure you have the
latest version, though.
Note that this is probably not a Linux-specific problem. Unless you
are compiling a program many other Linux users also compile, you
should not post your bug report to any of the comp.os.linux groups.
If the problem is not repeatable, you may be experiencing memory
corruption--see make says Error 139.
9.7 make says Error 139
Your compiler driver (gcc) dumped core. You probably have a corrupted,
buggy, or old version of GCC--get the latest release. Alternatively,
you may be running out of swap space--see My machine runs very
slowly when I run GCC / X / ....
If this doesn't fix the problem, you are probably having problems with
memory or disk corruption. Check that the clock rate, wait states, and
refresh timing for your SIMMS and cache are correct (hardware manuals
are sometimes wrong, too). If so, you may have some marginal SIMMS, or
a faulty motherboard or hard disk or controller.
Linux is a very good memory tester--much better than MS-DOS based
memory test programs.
Reportedly, some clone x87 math coprocessors can cause problems. Try
compiling a kernel with math emulation ( How do I
upgrade/recompile my kernel?.) You may need to use the "no387"
kernel command line flag on the LILO prompt to force the kernel to use
math emulation, or it may be able to work and still use the '387, with
the math emulation compiled in but mainly unused.
More information about this problem is available on the Web at
http://www.bitwizard.nl/sig11/.
9.8 shell-init: permission denied when I log in.
Your root directory and all the directories up to your home directory
must be readable and executable by everybody. See the manual page for
chmod or a book on Unix for how to fix the problem.
9.9 No utmp entry. You must exec ... when I log in.
Your /var/run/utmp is screwed up. You should have
> /var/run/utmp
in your /etc/rc.local or /etc/rc.d/*. See ("I have screwed up
my system and can't log in to fix it.") Note that the utmp may also
be found in /var/adm/ or /etc/ on some older systems.
9.10 Warning--bdflush not running.
Modern kernels use a better strategy for writing cached disk blocks.
In addition to the kernel changes, this involves replacing the old
update program which used to write everything every 30 seconds with a
more subtle daemon (actually a pair), known as bdflush.
Get bdflush-n.n.tar.gz from the same place as the kernel source code (
How do I upgrade/recompile my kernel?) and compile and install
it. Bdflush should be started before the usual boot-time file system
checks. It will work fine with older kernels as well, so there's no
need to keep the old update around.
9.11 Warning: obsolete routing request made.
This is nothing to worry about. The message means that your version
route is a little out of date, compared to the kernel. You can make
the message go away by getting a new version of route from the same
place as the kernel source code. ( How do I upgrade/recompile my
kernel?)
9.12 EXT2-fs: warning: mounting unchecked file system.
You need to run e2fsck (or fsck -t ext2 if you have the fsck front end
program) with the -a option to get it to clear the `dirty' flag, and
then cleanly unmount the partition during each shutdown.
The easiest way to do this is to get the latest fsck, umount, and
shutdown commands, available in Rik Faith's util-linux package (`
Where can I get Linux material by FTP?") You have to make sure
that your /etc/rc*/ scripts use them correctly.
NB: don't try to check a file system that's mounted read/write--this
includes the root partition if you don't see
VFS: mounted root ... read-only
at boot time. You must arrange to mount the root file system read/only
to start with, check it if necessary, and then remount it read/write.
Read the documentation that comes with util-linux to find out how to
do this.
Note that you need to specify the -n option to mount so it won't try
to update /etc/mtab, since the root file system is still read-only,
and this will otherwise cause it to fail.
9.13 EXT2-fs warning: maximal count reached.
This message is issued by the kernel when it mounts a file system
that's marked as clean, but whose "number of mounts since check"
counter has reached the predefined value. The solution is to get the
latest version of the ext2fs utilities (e2fsprogs-0.5b.tar.gz at the
time of writing) from the usual sites. (` Where can I get Linux
material by FTP?")
The maximal number of mounts value can be examined and changed using
the tune2fs program from this package.
9.14 EXT2-fs warning: checktime reached.
Kernels from 1.0 onwards support checking a file system based on the
elapsed time since the last check as well as by the number of mounts.
Get the latest version of the ext2fs utilities. "( EXT2-fs
warning: maximal count reached.")
9.15 df says Cannot read table of mounted file systems.
There is probably something wrong with your /etc/mtab or /etc/fstab
files. If you have a reasonably new version of mount, /etc/mtab should
be emptied or deleted at boot time (in /etc/rc.local or /etc/rc.d/*),
using something like
rm -f /etc/mtab*
Some versions of SLS have an entry for the root partition in /etc/mtab
made in /etc/rc* by using rdev. This is incorrect--the newer versions
of mount do this automatically.
Other versions of SLS have a line in /etc/fstab that looks like:
/dev/sdb1 /root ext2 defaults
This is wrong. /root should read simply /.
9.16 fdisk says Partition X has different physical/logical ...
If the partition number (X, above) is 1, this is the same problem as
in "fdisk: Partition 1 does not start on cylinder boundary."
If the partition begins or ends on a cylinder numbered greater than
1024, this is because the standard DOS disk geometry information
format in the partition table can't cope with cylinder numbers with
more than 10 bits. You should see "How can I get Linux to work
with my disk?"
9.17 fdisk: Partition 1 does not start on cylinder boundary.
The version of fdisk that comes with many Linux systems creates
partitions that fail its own validity checking. Unfortunately, if
you've already installed your system, there's not much you can do
about this, apart from copying the data off the partition, deleting
and remaking it, and copying the data back.
You can avoid the problem by getting the latest version of fdisk, from
Rik Faith's util-linux package (available on all the usual FTP sites).
Alternatively, if you are creating a new partition 1 that starts in
the first cylinder, you can do the following to get a partition that
fdisk likes.
* Create partition 1 in the normal way. A `p' listing will produce
the mismatch complaint.
* Type `u' to set sector mode and do `p' again. Copy down the number
from the "End" column.
* Delete partition 1.
* While still in sector mode, re-create partition 1. Set the first
sector to match the number of sectors per track. This is the
sector number in the first line of the `p' output. Set the last
sector to the value you wrote down in the step above.
* Type `u' to reset cylinder mode and continue with other
partitions.
Ignore the message about unallocated sectors--they refer to the
sectors on the first track apart from the Master Boot Record, and they
are not used if you start the first partition in track 2.
9.18 fdisk says partition n has an odd number of sectors.
The PC disk partitioning scheme works in 512-byte sectors, but Linux
uses 1K blocks. If you have a partition with an odd number of sectors,
the last sector is wasted. Ignore the message.
9.19 mtools says cannot initialize drive XYZ
This means that mtools is having trouble accessing the drive. This can
be due to several things.
Often this is due to the permissions on floppy drive devices
(/dev/fd0* and /dev/fd1*) being incorrect--the user running mtools
must have the appropriate access. See the manual page for chmod for
details.
Most versions of mtools distributed with Linux systems (not the
standard GNU version) use the contents of a file /etc/mtools to
determine which devices and densities to use, in place of having this
information compiled into the binary. Mistakes in this file often
cause problems. There is often no documentation about this.
For the easiest way to access your MS-DOS files (especially those on a
hard disk partition) see How do I access files on my DOS
partition or floppy? Note--you should never use mtools to access files
on an msdosfs mounted partition or disk!
9.20 At the start of booting: Memory tight
This means that you have an extra-large kernel, which means that Linux
has to do some special memory-management magic to be able to boot
itself from the BIOS. It isn't related to the amount of physical
memory in your machine. Ignore the message, or compile a kernel
containing only the drivers and features you need. ("How do I
upgrade/recompile my kernel?)"
9.21 My syslog says `end_request: I/O error, ...'.
This error message, and messages like it, almost always indicate a
hardware error with a hard drive.
This commonly indicates a hard drive defect. The only way to avoid
further data loss is to completely shut own the system. You must also
make sure that whatever data is on the drive is backed up, and restore
it to a non-defective hard drive.
This error message may also indicate a bad connection to the drive,
especially with homebrew systems. If you install an IDE drive, ALWAYS
use new cables. It's probably is a good idea with SCSI drives, too.
In one instance, this error also seemed to coincide with a bad ground
between the system board and the chassis. Be sure that all electrical
connections are clean and tight before placing the blame on the hard
drive itself.
[Peter Moulder, Theodore T'so]
9.22 You don't exist. Go away.
This is not a viral infection :-). It comes from programs like write,
talk, and wall, if your invoking UID doesn't correspond to a valid
user (probably due to /etc/passwd being corrupted), or if the session
(pseudoterminal, specifically) you're using isn't properly registered
in the utmp file (probably because you invoked it in a funny way).
10. The X Window System.
10.1 Does Linux support X?
Yes. Linux uses XFree86 (the current version is 3.3.2, which is based
on X11R6). You need to have a video card which is supported by
XFree86. See the Linux XFree86 HOWTO for more details.
Most Linux distributions nowadays come with an X installation.
However, you can install or upgrade your own, from
/pub/Linux/X11/Xfree86-* on sunsite.unc.edu and its mirror sites.
10.2 Where can I get an XF86Config for my system?
See the Linux XFree86 HOWTO, recent versions of Installation and
Getting Started, and the instructions for the XF86Setup program.
The contents of the XF86Config file depend on the your exact
combination of video card and monitor. It can either be configured by
hand, or using the XF86Setup utility. Read the instructions that came
with XFree86, in /usr/X11R6/lib/X11/etc. The file you probably need to
look at most is README.Config.
You should not use the sample XF86Config.eg file which is included
with newer versions of XFree86 verbatim, because the wrong video clock
settings can damage your monitor.
Please don't post to comp.os.linux.x asking for an XF86Config, and
please don't answer such requests.
10.3 xterm logins show up strangely in who, finger.
The xterm that comes with XFree86 2.1 and earlier doesn't correctly
understand the format that Linux uses for the /var/adm/utmp file,
where the system records who is logged in. It therefore doesn't set
all the information correctly.
The Xterms in XFree86 3.1 and later versions fix this problem.
10.4 I can't get X to work right.
Read the XFree86 HOWTO--note the question and answer section.
Try reading comp.windows.x.i386unix--specifically read the the FAQ for
that group.
Please don't post X or XFree86 related questions to comp.os.linux.x
unless they are Linux-specific.
11. Questions applicable to very out-of-date software.
The questions in this section are only relevant to users of software
that is at least three months old.
Please let me know if you find the answer to a problem you had here,
as unused questions in this section will eventually disappear. (See "
--
Robert Kiesling
[EMAIL PROTECTED]
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End of Linux-Misc Digest
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