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The Linux Bootdisk HOWTO
Tom Fawcett and Graham Chapman
v2.3, 4 April 1997
This document describes how to create Linux boot, boot/root and util
ity maintenance disks. These disks could be used as rescue disks or to
test new kernels. Note: if you haven't read the Linux FAQ and related
documents such as the Linux Installation HOWTO and the Linux Install
Guide, then you should not be trying to build boot diskettes.
1. Introduction
1.1. Why Build Boot Disks?
Linux boot disks are useful in a number of situations, such as:
· Testing a new kernel.
· Recovering from disk or system failure. Such a failure could be
anything from a lost boot sector to a disk head crash.
There are several ways of obtaining boot disks:
· Use one from a distribution such as Slackware. This will at least
allow you to boot.
· Use a rescue package to set up disks designed to be used as rescue
disks.
· Learn what is required for each of the various types of disk to
operate, then build your own.
I originally chose the last option - learn how it works so that you
can do it yourself. That way, if something breaks, you can work out
what to do to fix it. Plus you learn a lot about how Linux works along
the way.
Experienced Linux users may find little of use in this document.
However users new to Linux system administration who wish to protect
against root disk loss and other mishaps may find it useful.
A note on versions - this document has been updated to support the
following packages and versions:
· Linux 2.0.6
· LILO 0.19
Copyright (c) Tom Fawcett and Graham Chapman 1995, 1996, 1997.
Permission is granted for this material to be freely used and
distributed, provided the source is acknowledged. The copyright
conditions are intended to be no more restrictive than version 2 of
the GNU General Public License as published by the Free Software
Foundation.
No warranty of any kind is provided. You use this material at your own
risk.
1.2. Feedback and Credits
We welcome any feedback, good or bad, on the content of this document.
Please let us know if you find any errors or omissions. Send comments,
corrections and questions to Tom Fawcett (fawcett@nynexst.com) or
Graham Chapman (grahamc@zeta.org.au).
We thank the following people for correcting errors and providing
useful suggestions for improvement:
Randolph Bentson
Grant R. Bowman
Scott Burkett
Cameron Davidson
Bruce Elliot
Javier Ros Ganuza
HARIGUCHI Youichi
Duncan Hill
Bjxrn-Helge Mevik
Lincoln S. Peck
Dwight Spencer
Cameron Spitzer
Johannes Stille
1.3. Change History
v.2.3, 4 April 1997. Changes in this version:
· Moved first FAQ question ("Why doesn't my disk boot?") into its
own section ("Troubleshooting") and added Yard troubleshooting
information to it.
· Made a few changes suggested by D.Hill and J.R.Ganuza.
· Added ref and label tags in various places.
· Moved scripts and resources to appendices.
· Added URLs for distributions' bootdisks plus mirrors.
v2.2, 1 September 1996. Changes in this version:
· Fix: set ramdisk word via rdev on /dev/fd0 instead of zImage.
v2.1, 18 August 1996. Changes in this version:
Summary: this was a major cleanup to reflect changes between kernel
version 1.2 and 2.0. Specific changes are:
· Chg: replaced shell scripts and directory listings.
· Chg: removed most of the text of "oversize ramdisk" FAQ question.
· Fix: mkfs -i should have been mke2fs -i.
· Fix: missing parameter name in dd command to zero rootdisk device.
· Fix: remove accidental extra parameter from mke2fs command to
create rootdisk filesystem.
· Chg: minor changes to reflect less reliance on the Bootkit utility.
· Chg: change section cross-references to refer to section title, not
number (sometime I'll add hypertext links...)
· Add: use cpio as an alternate way of copying files.
· Add: tips for removing unnecessary device special files.
· Add: FAQ question - what to do if nothing happens at boot time.
· Add: various minor changes.
v2.0, 12 June 1996. Changes in this version:
· Add: additional author and maintainer, Tom Fawcett.
· Add: section 6.3, Ramdisk Usage.
· Add: section titled Advanced Bootdisk Creation, which describes how
to take advantage of ramdisk changes in kernels 1.3.48+
· Chg: rewrite section on /lib directory.
· Chg: various minor tips on changed ramdisk usage.
Version history:
· v1.02, 25 June 1995 - minor changes.
· v1.01, 6 February 1995 - minor changes.
· v1.0, 2 January 1995 - first release in standard HOWTO layout.
· v0.10, 1 Novemer 1994 - original version, labelled "Draft".
2. Disks
2.1. Summary of Disk Types
I classify boot-related disks into four types. The discussion here and
throughout this document uses the term "disk" to refer to diskettes
unless otherwise specified. Most of the discussion could be equally
well applied to hard disks.
A summary of disk types and uses is:
boot
A disk containing a kernel which can be booted. The disk can
contain a filesystem and use a boot loader to boot, or it can
simply contain the kernel only at the start of the disk. The
disk can be used to boot the kernel using a root file system on
another disk. This could be useful if you lost your boot loader
due to, for example, an incorrect installation attempt.
root
A disk with a file system containing everything required to run
a Linux system. It does not necessarily contain either a kernel
or a boot loader.
This disk can be used to run the system independently of any
other disks, once the kernel has been booted. A special kernel
feature allows a separate root disk to be mounted after booting,
with the root disk being automatically copied to a ramdisk.
You could use this type of disk to check another disk for
corruption without mounting it, or to restore another disk after
a disk failure or loss of files.
boot/root
A disk which is the same as a root disk, but contains a kernel
and a boot loader. It can be used to boot from, and to run the
system. The advantage of this type of disk is that is it compact
- everything required is on a single disk. However the
gradually increasing size of everything means that it won't
necessarily always be possbile to fit everything on a single
diskette, even with compression.
utility
A disk which contains a file system, but is not intended to be
mounted as a root file system. It is an additional data disk.
You would use this type of disk to carry additional utilities
where you have too much to fit on your root disk.
The term "utility" only really applies to diskettes, where you
would use a utility disk to store additional recovery utility
software.
The most flexible approach for rescue diskettes is probably to use
separate boot and root diskettes, and one or more utility diskettes to
handle the overflow.
2.2. Boot
2.2.1. Overview
All PC systems start the boot process by executing code in ROM to load
the sector from sector 0, cylinder 0 of the boot drive and try and
execute it. On most bootable disks, sector 0, cylinder 0 contains
either:
· code from a boot loader such as LILO, which locates the kernel,
loads it and executes it to start the boot proper.
· the start of an operating system kernel, such as Linux.
If a Linux kernel has been written to a diskette as a raw device, then
the first sector will be the first sector of the Linux kernel itself,
and this sector will continue the boot process by loading the rest of
the kernel and running Linux. For a more detailed description of the
boot sector contents, see the documentation in lilo-01.5 or higher.
An alternative method of storing a kernel on a boot disk is to create
a filesystem, not as a root filesystem, but simply as a means of
installing LILO and thus allowing boot-time command line options to be
specified. For example, the same kernel could then be used to boot
using a hard disk root filesystem, or a diskette root filesystem. This
could be useful if you were trying to rebuild the hard disk
filesystem, and wanted to repeatedly test results.
2.2.2. Setting Pointer to Root
The kernel must somehow obtain a pointer to the drive and partititon
to be mounted as the root drive. This can be provided in several ways:
· By setting ROOT_DEV = devicename in the Linux kernel makefile and
rebuilding the kernel (for advice on how to rebuild the kernel,
read the Linux FAQ and look in /usr/src/linux). Comments in the
Linux makefile describe the valid values for devicename.
· By running the rdev utility:
rdev filename devicename
This will set the root device of the kernel contained in filename to
be devicename. For example:
rdev zImage /dev/sda1
This sets the root device in the kernel in zImage to the first parti
tion on the first SCSI drive.
There are some alternative ways of issuing the rdev command. Try:
rdev -h
and it will display command usage.
There is usually no need to configure the root device for boot
diskette use, because the kernel currently used to boot from probably
already points to the root drive device. The need can arise, howoever,
if you obtain a kernel from another machine, for example, from a
distribution, or if you want to use the kernel to boot a root
diskette. It is probably a good idea to check the current root drive
setting, just in case it is wrong. To get rdev to check the current
root device in a kernel file, enter the command:
rdev <filename>
It is possible to change the root device set in a kernel by means
other than using rdev. For details, see the FAQ at the end of this
document.
2.2.3. Copying Kernel to Boot Diskette
Once the kernel has been configured it must be copied to the boot
diskette.
The commands described below (and throughout the HOWTO) assume that
the diskettes have been formatted. If not, then use fdformat to format
the diskettes before continuing.
If the disk is not intended to contain a file system, then the kernel
can be copied using the dd command, as follows:
dd if=infilename of=devicename
where infilename is the name of the kernel
and devicename is the diskette raw device,
usually /dev/fd0
The cp command can also be used:
cp filename devicename
For example:
dd if=zImage of=/dev/fd0
or
cp zImage /dev/fd0
The seek parameter to the dd command should NOT be used. The file must
be copied to start at the boot sector (sector 0, cylinder 0), and
omitting the seek parameter will do this.
The output device name to be used is usually /dev/fd0 for the primary
diskette drive (i.e. drive "A:" in DOS), and /dev/fd1 for the
secondary. These device names will cause the kernel to autodetect the
attributes of the drives. Drive attributes can be specified to the
kernel by using other device names: for example /dev/fd0H1440
specifies a high density 1.44 Mb drive. It is rare to need to use
these specific device names.
Where the kernel is to be copied to a boot disk containing a
filesystem, then the disk is mounted at a suitable point in a
currently-mounted filesystem, then the cp command is used. For
example:
mount -t ext2 /dev/fd0 /mnt
cp zImage /mnt
umount /mnt
Note that for almost all operations in this HOWTO, the user should be
operating as the superuser.
2.3. Root
2.3.1. Overview
A root disk contains a complete working Linux system, but without
necessarily including a kernel. In other words, the disk may not be
bootable, but once the kernel is running, the root disk contains
everything needed to support a full Linux system. To be able to do
this, the disk must include the minimum requirements for a Linux
system:
· File system.
· Minimum set of directories - dev, proc, bin, etc, lib, usr, tmp.
· Basic set of utilities - bash (to run a shell), ls, cp etc.
· Minimum set of config files - rc, inittab, fstab etc.
· Runtime library to provide basic functions used by utilities.
Of course, any system only becomes useful when you can run something
on it, and a root diskette usually only becomes useful when you can do
something like:
· Check a file system on another drive, for example to check your
root file system on your hard drive, you need to be able to boot
Linux from another drive, as you can with a root diskette system.
Then you can run fsck on your original root drive while it is not
mounted.
· Restore all or part of your original root drive from backup using
archive/compression utilities including cpio, tar, gzip and ftape.
2.4. Boot/Root
This is essentially the same as the root disk, with the addition of a
kernel and a boot loader such as LILO.
With this configuration, a kernel file is copied to the root file
system, and LILO is then run to install a configuration which points
to the kernel file on the target disk. At boot time, LILO will boot
the kernel from the target disk.
Several files must be copied to the diskette for this method to work.
Details of these files and the required LILO configuration, including
a working sample, are given below in the section titled "LILO".
2.4.1. RAM Disks and Root Filesystems on Diskette
For a diskette root filesystem to be efficient, you need to be able to
run it from a ramdisk, i.e. an emulated disk drive in main memory.
This avoids having the system run at a snail's pace, which a diskette
would impose. The Ftape HOWTO states that a ramdisk will be required
when using Ftape because Ftape requires exclusive use of the diskette
controller.
There is an added benefit from using a ramdisk - the Linux kernel
includes an automatic ramdisk root feature, whereby it will, under
certain circumstances, automatically copy the contents of a root
diskette to a ramdisk, and then switch the root drive to be the
ramdisk instead of the diskette. This has three major benefits:
· The system runs a lot faster.
· The diskette drive is freed up to allow other diskettes to be used
on a single-diskette drive system.
· With compression, the ramdisk image on a disk can be substantially
smaller than (eg, 40% the size of) the corresponding disk image.
This means that a 1.44 meg floppy disk may hold a root containing
roughly 3.6 meg.
For kernels 1.3.48+, the ramdisk code was substantially rewritten.
You have some more options and the commands for using the ramdisk are
somewhat different. Section ``Advanced Bootdisk Creation'', below,
discusses how to take advantage of these.
You must configure your kernel to have ramdisk support, but the
ramdisk is dynamically expandible so you need not specify the size.
rdev -r is no longer used to specify the ramdisk size, but instead
sets a ramdisk word in the kernel image. Section ``Advanced Bootdisk
Creation'' discusses this in more detail.
If you have a kernel before 1.3.48, the following requirements apply.
Note that this applies ONLY to kernels prior to 1.3.48.
· The file system on the diskette drive must be either a minix or an
ext2 file system. The ext2 file system is generally the preferred
file system to use. Note that if you have a Linux kernel earlier
than 1.1.73, then you should see the comments in the section titled
"File Systems" to see whether your kernel will support ext2. If
your kernel is old then you may have to use minix. This will not
cause any significant problems.
· A ramdisk must be configured into the kernel, and it must be at
least as big as the diskette drive.
A ramdisk can be configured into the kernel in several ways:
· By uncommenting the RAMDISK macro in the Linux kernel makefile, so
that it reads:
RAMDISK = -DRAMDISK=1440
to define a ramdisk of 1440 1K blocks, the size of a high-density
diskette.
· By running the rdev utility, available on most Linux systems. This
utility displays or sets values for several things in the kernel,
including the desired size for a ramdisk. To configure a ramdisk of
1440 blocks into a kernel in a file named zImage, enter:
rdev -r zImage 1440
this might change in the future, of course. To see what your version
of rdev does, enter the command:
rdev -h
and it should display its options.
· By using the boot loader package LILO to configure it into your
kernel at boot time. This can be done using the LILO configuration
parameter:
ramdisk = 1440
to request a ramdisk of 1440 1K blocks at boot time.
· By interrupting a LILO automatic boot and adding ramdisk=1440 to
the command line. For example, such a command line might be:
zImage ramdisk=1440
See the section on LILO for more details.
· By editing the kernel file and altering the values near the start
of the file which record the ramdisk size. This is definitely a
last resort, but can be done. See the FAQ near the end of this
document for more details.
The easiest of these methods is LILO configuration, because you need
to set up a LILO configuration file anyway, so why not add the ramdisk
size here?
LILO configuration is briefly described in a section titled "LILO"
below, but it is advisable to obtain the latest stable version of LILO
from your nearest Linux mirror site, and read the documentation that
comes with it.
Ramdisks can be made larger than the size of a diskette, and made to
contain a filesystem as large as the ramdisk. This can be useful to
load all the software required for rescue work onto a single high-
performance ramdisk. The method of doing this is described in the FAQ
section under the question "How can I create an oversize ramdisk
filesystem?"
2.5. Utility
Often one disk is not sufficient to hold all the software you need to
be able to perform rescue functions of analysing, repairing and
restoring corrupted disk drives. By the time you include tar, gzip
e2fsck, fdisk, Ftape and so on, there is enough for a whole new
diskette, maybe even more if you want lots of tools.
This means that a rescue set often requires a utility diskette, with a
file system containing any extra files required. This file system can
then be mounted at a convenient point, such as /usr, on the boot/root
system.
Creating a file system is fairly easy, and is described in the section
titled "File Systems".
3. Components
3.1. File Systems
The Linux kernel now supports two file system types for root disks to
be automatically copied to ramdisk. These are minix and ext2, of
which ext2 is the preferred file system. The ext2 support was added
sometime between 1.1.17 and 1.1.57, I'm not sure exactly which. If
you have a kernel within this range then edit
/usr/src/linux/drivers/block/ramdisk.c and look for the word "ext2".
If it is not found, then you will have to use a minix file system, and
therefore the "mkfs" command to create it. If using ext2, then you
may find it useful to use the -i option to specify more inodes than
the default; -i 2000 is suggested so that you don't run out of inodes.
Alternatively, you can save on inodes by removing lots of unnecessary
/dev files. Mke2fs will by default create 360 inodes on a 1.44Mb
diskette. I find that 120 inodes is ample on my current rescue root
diskette, but if you include all the devices in the /dev directory
then you will easily exceed 360. Using a compressed root filesystem
allows a larger filesystem, and hence more inodes by default, but you
may still need to either reduce the number of files or increase the
number of inodes.
To create an ext2 file system on a diskette on my system, I issue the
following command:
mke2fs -m 0 /dev/fd0
The mke2fs command will automatically detect the space available and
configure itself accordingly. If desired, the diskette size in 1Kb
blocks can be specified to speed up mke2fs operation. The -m 0
parameter prevents it from reserving space for root, and hence
provides more usable space on the disk.
An easy way to test the result is to create a system using the above
command or similar, and then attempt to mount the diskette. If it is
an ext2 system, then the command:
mount -t ext2 /dev/fd0 /<mount point>
should work.
3.2. Kernel
3.2.1. Building a Custom Kernel
In most cases it would be possible to copy your current kernel and
boot the diskette from that. However there may be cases where you
wish to build a separate one.
One reason is size. The kernel is one of the largest files in a
minimum system, so if you want to build a boot/root diskette, then you
will have to reduce the size of the kernel as much as possible. The
kernel now supports changing the diskette after booting and before
mounting root, so it is not necessary any more to squeeze the kernel
into the same disk as everything else, therefore these comments apply
only if you choose to build a boot/root diskette.
There are two ways of reducing kernel size:
· Building it with the minumum set of facilities necessary to support
the desired system. This means leaving out everything you don't
need. Networking is a good thing to leave out, as well as support
for any disk drives and other devices which you don't need when
running your boot/root system.
· Compressing it, using the standard compressed-kernel option
included in the makefile:
make zImage
Refer to the documentation included with the kernel source for up-to-
date information on building compressed kernels. Note that the kernel
source is usually in /usr/src/linux.
Having worked out a minimum set of facilities to include in a kernel,
you then need to work out what to add back in. Probably the most
common uses for a boot/root diskette system would be to examine and
restore a corrupted root file system, and to do this you may need
kernel support.
For example, if your backups are all held on tape using Ftape to
access your tape drive, then, if you lose your current root drive and
drives containing Ftape, then you will not be able to restore from
your backup tapes. You will have to reinstall Linux, download and
reinstall Ftape, and then try and read your backups.
It is probably desirable to maintain a copy of the same version of
backup utilities used to write the backups, so that you don't waste
time trying to install versions that cannot read your backup tapes.
The point here is that, whatever I/O support you have added to your
kernel to support backups should also be added into your boot/root
kernel.
The procedure for actually building the kernel is described in the
documentation that comes with the kernel. It is quite easy to follow,
so start by looking in /usr/src/linux. Note that if you have trouble
building a kernel, then you should probably not attempt to build
boot/root systems anyway.
3.3. Devices
A /dev directory containing a special file for all devices to be used
by the system is mandatory for any Linux system. The directory itself
is a normal directory, and can be created with the mkdir command in
the normal way. The device special files, however, must be created in
a special way, using the mknod command.
There is a shortcut, though --- copy your existing /dev directory
contents, and delete the ones you don't want. The only requirement is
that you copy the device special files using the -R option. (--
Warning: The cp command supplied with the most recent version of
fileutils (3.13) is reported not to respect the -R flag.--)
This will copy the directory without attempting to copy the contents
of the files. Note that if you use lower caser, as in "-r", there will
be a vast difference, because you will probably end up copying the
entire contents of all of your hard disks - or at least as much of
them as will fit on a diskette! Therefore, take care, and use the
command:
cp -dpR /dev /mnt
assuming that the diskette is mounted at /mnt. The dp switches ensure
that symbolic links are copied as links (rather than the target file
being copied) and that the original file attributes are preserved,
thus preserving ownership information.
You can also use the -p option of cpio, because cpio will handle
device special files correctly, and not try and copy the contents.
For example:
cd /dev
find . -print | cpio -pmd /mnt/dev
will copy all device special files from /dev to /mnt/dev. In fact it
will copy all files in the directory tree starting at /dev, and will
create any required subdirectories in the target directory tree.
If you want to do it the hard way, use ls -l to display the major and
minor device numbers for the devices you want, and create them on the
diskette using mknod.
Many distributions include a shell script called MAKEDEV in the /dev
directory. This shell script could be used to create the devices, but
it is probably easier to just copy your existing ones, especially for
rescue disk purposes.
Whichever way the device directory is copied, it is worth checking
that any special devices you need have been placed on the rescue
diskette. For example, Ftape uses tape devices, so you will need to
copy all of these.
Note that an inode is required for each device special file, and
inodes can at times be a scarce resource, especially on diskette
filesystems. It therefore makes sense to remove any device special
files that you don't need from the diskette /dev directory. Many
devices are obviously unnecessary on specific systems. For example, if
you do not have SCSI disks, then you can safely remove all the device
files starting with "sd". Similarly, if you don't intend to use your
serial port then all the device files starting with "cua" can go.
3.4. Directories
It might be possible to get away with just /dev, /proc and /etc to run
a Linux system. I don't know - I've never tested it. However it will
certainly be difficult, because without shared libraries all your
executables would have to be statically linked. A reasonable minimum
set of directories consists of the following:
/dev
Required to perform I/O with devices
/proc
Required by the ps command
/etc
System configuration files
/bin
Utility executables considered part of the system
/lib
Shared libraries to provide run-time support
/mnt
A mount point for maintenance on other disks
/usr
Additional utilities and applications
Note that the directory tree presented here is for root diskette use
only. Refer to the Linux File System Standard for much better
information on how file systems should be structured in "standard"
Linux systems.
Four of these directories can be created very easily:
· /dev is described above in the section titled DEVICES.
· /proc only needs to exist. Once the directory is created using
mkdir, nothing more is required.
· Of the others, /mnt and /usr are included in this list only as
mount points for use after the boot/root system is running. Hence
again, these directories only need to be created.
The remaining 3 directories are described in the following sections.
3.4.1. /etc
This directory must contain a number of configuration files. On most
systems, these can be divided into 3 groups:
· Required at all times, e.g. rc, fstab, passwd.
· May be required, but no-one is too sure.
· Junk that crept in.
Files which are not essential can be identified with the command:
ls -ltru
This lists files in reverse order of date last accessed, so if any
files are not being accessed, then they can be omitted from a root
diskette.
On my root diskettes, I have the number of config files down to 15.
This reduces my work to dealing with three sets of files:
· The ones I must configure for a boot/root system:
rc.d/* system startup and run level change scripts
fstab list of file systems to be mounted
inittab parameters for the init process - the
first process started at boot time.
· the ones I should tidy up for a boot/root system:
passwd list of logins
shadow contains passwords
These should be pruned on secure systems to avoid copying user's pass
words off the system, and so that when you boot from diskette,
unwanted logins are rejected. (-- Note that there is a reason not to
prune passwd and shadow. Tar (and probably other archivers) stores
user and group names with files. If you restore files to your hard
disk from tape, the files will be restored with their original names.
If these names do not exist in passwd/group when they are restored,
the UID/GID will not be correct.--)
· The rest. They work at the moment, so I leave them alone.
Out of this, I only really have to configure two files, and what they
should contain is surprisingly small.
· rc should contain:
#!/bin/sh
/etc/mount -av
/bin/hostname boot_root
and I don't really need to run hostname - it just looks nicer if I do.
Even mount is actually only needed to mount /proc to support the ps
command - Linux will run without it, although rescue operations are
rather limited without mount!
· fstab should contain:
/dev/ram / ext2 defaults
/dev/fd0 / ext2 defaults
/proc /proc proc defaults
I don't think that the first entry is really needed, but I find that
if I leave it out, mount won't mount /proc.
Inittab should be ok as is, unless you want to ensure that users on
serial ports cannot login. To prevent this, comment out all the
entries for /etc/getty which include a ttys or ttyS device at the end
of the line. Leave in the tty ports so that you can login at the
console.
Inittab defines what the system will run or rerun in various states
including startup, move to multi-user mode, powerfail, and others. A
point to be careful of here is to carefully check that the commands
entered in inittab refer to programs which are present and to the
correct directory. If you place your command files on your rescue disk
using the sample directory listing in this HOWTO as a guide, and then
copy your inittab to your rescue disk without checking it, then the
probability of failure will be quite high, because half of the inittab
entries will refer to missing programs or to the wrong directory.
It is worth noting here as well that some programs cannot be moved
from one directory to another or they will fail at runtime because
they have hardcoded the name of another program which they attempt to
run. For example on my system, /etc/shutdown has hardcoded in it
/etc/reboot. If I move reboot to /bin/reboot, and then issue a
shutdown command, it will fail because it can't find the reboot file.
For the rest, just copy all the text files in your /etc directory,
plus all the executables in your /etc directory that you cannot be
sure you do not need. As a guide, consult the sample ls listing in
"Sample Boot/Root ls-lR Directory Listing" - this is what I have, so
probably it will be sufficient for you if you copy only those files -
but note that systems differ a great deal, so you cannot be sure that
the same set of files on your system is equivalent to the files on
mine. The only sure method is to start with inittab and work out what
is required.
Most systems now use an /etc/rc.d directory containing shell scripts
for different run levels. The absolute minimum is a single rc script,
but it will probably be a lot simpler in practice to copy the inittab
and /etc/rc.d directory from your existing system, and prune the shell
scripts in the rc.d directory to remove processing not relevent to a
diskette system environment.
3.4.2. /bin
Here is a convenient point to place the extra utilities you need to
perform basic operations, utilities such as ls, mv, cat, dd etc.
See the section titled "Sample Boot/Root ls-lR Directory Listing" for
the list of files that I place in my boot/root /bin directory. You may
notice that it does not include any of the utilities required to
restore from backup, such as cpio, tar, gzip etc. That is because I
place these on a separate utility diskette, to save space on the
boot/root diskette. Once I have booted my boot/root diskette, it then
copies itself to the ramdisk leaving the diskette drive free to mount
another diskette, the utility diskette. I usually mount this as /usr.
Creation of a utility diskette is described below in the section
titled "Adding Utility Diskettes".
3.4.3. /lib
In /lib you place necessary shared libraries and loaders. If the
necessary libraries are not found in your /lib directory then the
system will be unable to boot. If you're lucky you may see an error
message telling you why.
Nearly every program requires at least the libc library:
libc.so.X
where X is the current version number. Check your /lib directory.
Note that libc.so.4 may be a symlink to a libc library with version
number in the filename. If you issue the command:
ls -l /lib
you will see something like:
libc.so.4 -> libc.so.4.5.21
In this case, the libc library you want is libc.so.4.5.21. This is an
example only - the ELF libc library is currently libc.so.5.xxxx.
To find other libraries you should go through all the binaries you
plan to include and check their dependencies. You can do this with
ldd command. For example, on my system the command:
ldd /bin/mount
produces the output:
/bin/mount:
libc.so.5 => /lib/libc.so.5.2.18
indicating that /bin/mount needs the library libc.so.5, which is a
symbolic link to libc.so.5.2.18.
In /lib you must also include one or more loaders to load the
libraries. The loader file is either ld.so (for a.out libraries) or
ld-linux.so (for ELF libraries). If you're not sure which you need,
run the "file" command on the library. For example, on my system:
file /lib/libc.so.5.2.18
tells me:
/lib/libc.so.5.2.18: ELF 32-bit LSB shared object ...
so it needs an ELF loader. If you have an a.out library you'll
instead see something like:
/lib/libc.so.4.7.2: Linux/i386 demand-paged executable (QMAGIC) ...
Copy the specific loader(s) you need.
Libraries and loaders should be checked carefully against the included
binaries. If the kernel cannot load a necessary library, the kernel
will usually hang with no error message.
3.5. LILO
3.5.1. Overview
For the boot/root to be any use, it must be bootable. To achieve this,
the easiest way is to install a boot loader, which is a piece of
executable code stored at sector 0, cylinder 0 of the diskette. See
the section above titled "BOOT DISKETTE" for an overview of the boot
process.
LILO is a tried and trusted boot loader available from any Linux
mirror site. It allows you to configure the boot loader, including:
· Which device is to be mounted as the root drive.
· Whether to use a ramdisk.
3.5.2. Sample LILO Configuration
This provides a very convenient place to specify to the kernel how it
should boot. My root/boot LILO configuration file, used with LILO
0.15, is:
______________________________________________________________________
boot = /dev/fd0
install = ./mnt/boot.b
map = ./mnt/lilo.map
delay = 50
message = ./mnt/lilo.msg
timeout = 150
compact
image = ./mnt/zImage
ramdisk = 1440
root = /dev/fd0
______________________________________________________________________
Note that I have not tested this recently, because I no longer use
LILO-based boot/root diskettes. There is no reason to suppose that it
does not still work, but if you try it and it fails, you must read the
LILO documentation to find out why.
Note also that boot/root systems no longer rely on LILO, because since
1.3.48, the kernel supports loading a compressed root filesystem from
the same diskette as the kernel. See section ``Advanced Bootdisk
Creation'' for details.
If you have a kernel later than 1.3.48, the "ramdisk = 1440" line is
unnecessary and should be removed.
Note that boot.b, lilo.msg and the kernel must first have been copied
to the diskette using a command similar to:
______________________________________________________________________
cp /boot/boot.b ./mnt
______________________________________________________________________
If this is not done, then LILO will not run correctly at boot time if
the hard disk is not available, and there is little point setting up a
rescue disk which requires a hard disk in order to boot.
I run lilo using the command:
/sbin/lilo -C <configfile>
I run it from the directory containing the mnt directory where I have
mounted the diskette. This means that I am telling LILO to install a
boot loader on the boot device (/dev/fd0 in this case), to boot a
kernel in the root directory of the diskette.
I have also specified that I want the root device to be the diskette,
and I want a ramdisk created of 1440 1K blocks, the same size as the
diskette. Since I have created an ext2 file system on the diskette,
this completes all the conditions required for Linux to automatically
switch the root device to the ramdisk, and copy the diskette contents
there as well.
The ramdisk features of Linux are described further in the section
above titled "RAM DISKS AND BOOT/ROOT SYSTEMS".
It is also worth considering using the "single" parameter to cause
Linux to boot in single-user mode. This could be useful to prevent
users logging in on serial ports.
I also use the "DELAY" "MESSAGE" and "TIMEOUT" statements so that when
I boot the disk, LILO will give me the opportunity to enter command
line options if I wish. I don't need them at present, but I never know
when I might want to set a different root device or mount a filesystem
read-only.
The message file I use contains the message:
Linux Boot/Root Diskette
========================
Enter a command line of the form:
zImage [ command-line options]
If nothing is entered, linux will be loaded with
defaults after 15 seconds.
This is simply a reminder to myself what my choices are.
Readers are urged to read the LILO documentation carefully before
atttempting to install anything. It is relatively easy to destroy
partitions if you use the wrong "boot = " parameter. If you are
inexperienced, do NOT run LILO until you are sure you understand it
and you have triple-checked your parameters.
Note that you must re-run LILO every time you change the kernel, so
that LILO can set up its map file to correctly describe the new kernel
file. It is in fact possible to replace the kernel file with one which
is almost identical without rerunning LILO, but it is far better not
to gamble - if you change the kernel, re-run LILO.
3.5.3. Removing LILO
One other thing I might as well add here while I'm on the LILO topic:
if you mess up lilo on a drive containing DOS, you can always replace
the boot sector with the DOS boot loader by issuing the DOS command:
FDISK /MBR
where MBR stands for "Master Boot Record". Note that some purists
disagree with this, and they may have grounds, but it works.
3.5.4. Useful LILO Options
LILO has several useful options which are worth keeping in mind when
building boot disks:
· Command line options - you can enter command line options to set
the root device, ramdisk size (for kernels less than 1.3.48),
special device parameters, or other things. If you include the
DELAY = nn statement in your LILO configuration file, then LILO
will pause to allow you to select a kernel image to boot, and to
enter, on the same line, any options. For example:
zImage aha152x=0x340,11,3,1 ro
will pass the aha152x parameters through to the aha152x scsi disk
driver (provided that driver has been included when the kernel was
built) and will ask for the root filesystem to be mounted read-only.
· Command line "lock" option - this option asks LILO to store the
command line entered as the default command line to be used for all
future boots. This is particularly useful where you have a device
which cannot be autoselected. By using "lock" you can avoid having
to type in the device parameter string every time you boot. For
example:
zImage aha152x=0x340,11,3,1 root=/dev/sda8 ro lock
· APPEND configuration statement - this allows device parameter
strings to be stored in the configuration, as an alternative to
using the "lock" command line option. Note that any keywords of the
form word=value MUST be enclosed in quotes. For example:
APPEND = "aha152x=0x340,11,3,1"
· DELAY configuration statement - this pauses for DELAY tenths of
seconds and allows the user to interrupt the automatic boot of the
default command line, so that the user can enter an alternate
command line.
4. Advanced Bootdisk Creation
4.1. Overview
Previous sections of this document covered the basics of creating
boot/root disks, and are applicable to nearly all kernels up to the
present (2.0, the latest stable kernel).
Kernels 1.3.48+ involved a substantial rewrite of the ramdisk code,
adding significant new capabilities. These kernels could
automatically detect compressed filesystems, uncompress them and load
them into the ramdisk on boot-up. Root filesystems could be placed on
a second disk, and as of kernel 1.3.98 or so, ramdisks are dynamically
expandable.
Altogether, these new capabilities mean that boot disks can contain
substantially more than they used to. With compression, a 1722K disk
may now hold up to about 3.5 megs of files. As anyone who has created
bootdisks knows, much time is spent pruning down the file set and
finding trimmed-down versions of files that will all fit in a small
filesystem. With the new capabilities this is no longer such a
concern.
Unfortunately, creating bootdisks to exploit these new features is
slightly more difficult now. To build a compressed filesystem on a
floppy, the filesystem has to be built on another device and then
compressed and transferred to the floppy. This means a few more
steps.
The basic strategy is to create a compressed root filesystem, copy the
kernel to the floppy disk, tell the kernel where to find the root
filesystem, then copy the compressed root filesystem to the floppy.
Here's a simple ASCII drawing of what the disk will look like:
|<--- zImage --->|<------ Compressed root filesystem -------->|
|________________|____________________________________________|
Floppy disk space
Here are the steps to create the boot floppy:
4.2. Creating a root filesystem
The root filesystem is created pretty much the same way as outlined in
Section 2.3 of this document. The primary difference is that you can
no longer create a root filesystem directly on a floppy -- you must
create it on a separate device larger than the floppy area it will
occupy.
4.2.1. Choosing a device
In order to build such a root filesystem, you need a spare device that
is large enough. There are several choices:
· If you have an unused hard disk partition that is large enough
(several megabytes), this is the easiest solution. Alternatively,
if you have enough physical RAM you can simply turn off swapping
and build the filesystem in your swap partition.
However, most people don't have a spare partition and can't afford
to turn swapping off, so...
· Use a loopback device. A loopback device allows a disk file on an
existing filesystem to be treated as a device. In order to use
loopback devices you need specially modified mount and unmount
programs. You can find these at:
ftp://ftp.win.tue.nl:/pub/linux/util/mount-2.5X.tar.gz
where X is the latest modification letter.
If you do not have loop devices (/dev/loop0, /dev/loop1, etc) on your
system, you'll have to create them first. The commands:
mknod /dev/loop0 b 7 0
mknod /dev/loop1 b 7 1
mknod /dev/loop2 b 7 2
...
will do this. You probably only need loop0.
One you've installed these special mount/umount binaries, create a
temporary file on a hard disk with enough capacity (eg, /tmp/fsfile).
You can use a command like
dd if=/dev/zero of=/tmp/fsfile bs=1k count=nnn
to create an nnn-block file.
Use the file name in place of DEVICE below. When you issue a mount
command you must include the option "-o loop" to tell mount to use a
loopback device. For example:
mount -o loop -t ext2 /tmp/fsfile /mnt
will mount /tmp/fsfile (via a loopback device) at the mount point
/mnt. A 'df' will confirm this.
· A final option is to use the ramdisk (DEVICE = /dev/ram0 or
/dev/ramdisk). In this case, memory is used to simulate a disk
drive. The ramdisk must be large enough to hold a filesystem of
the appropriate size. Check your Lilo configuration file
(/etc/lilo.conf) for a line like:
RAMDISK_SIZE = nnn
which determines how much RAM will be allocated. The default is
4096K.
After you've chosen one of these options, prepare the device with:
dd if=/dev/zero of=DEVICE bs=1k count=3000
This command zeroes out the device. This step is important because
the filesystem on the device will be compressed later, so all unused
portions should be filled with zeroes to achieve maximum compression.
Next, create the filesystem with:
mke2fs -m 0 DEVICE
(If you're using a loopback device, the disk file you're using should
be supplied in place of this DEVICE. In this case, mke2fs will ask if
you really want to do this; say yes.)
Then mount the device:
mount -t ext2 DEVICE /mnt
Proceed as before, copying have set these values then you can write the file to a
diskette using either Norton Utilities Disk Editor, or a program
called rawrite.exe. This program is included in several distributions,
including the SLS and Slackware distributions. It is a DOS program
which writes a file to the "raw" disk, starting at the boot sector,
instead of writing it to the file system. If you use Norton Utilities,
then you must write the file to a physical disk starting at the
beginning of the disk.
6.6. Q. How can I make extra copies of boot/root diskettes?
It is never desirable to have just one set of rescue disks - 2 or 3
should be kept in case one is unreadable.
The easiest way of making copies of any diskettes, including bootable
and utility diskettes, is to use the dd command to copy the contents
of the original diskette to a file on your hard drive, and then use
the same command to copy the file back to a new diskette. Note that
you do not need to, and should not, mount the diskettes, because dd
uses the raw device interface.
To copy the original, enter the command:
dd if=devicename of=filename
where devicename the device name of the diskette
drive
and filename the name of the file where you
want to copy to
For example, to copy from /dev/fd0 to a temporary file called
/tmp/diskette.copy, I would enter the command:
dd if=/dev/fd0 of=/tmp/diskette.copy
Omitting the "count" parameter, as we have done here, means that the
whole diskette of 2880 (for a high-density) blocks will be copied.
To copy the resulting file back to a new diskette, insert the new
diskette and enter the reverse command:
dd if=filename of=devicename
Note that the above discussion assumes that you have only one diskette
drive. If you have two of the same type, then you can copy diskettes
using a command like:
dd if=/dev/fd0 of=/dev/fd1
6.7. Q. How can I boot without typing in "ahaxxxx=nn,nn,nn" every
time?
Where a disk device cannot be autodetected it is necessary to supply
the kernel with a command device parameter string, such as:
aha152x=0x340,11,3,1
This parameter string can be supplied in several ways using LILO:
· By entering it on the command line every time the system is booted
via LILO. This is boring, though.
· By using the LILO "lock" keyword to make it store the command line
as the default command line, so that LILO will use the same options
every time it boots.
· By using the APPEND statement in the lilo config file. Note that
the parameter string must be enclosed in quotes.
For example, a sample command line using the above parameter string
would be:
zImage aha152x=0x340,11,3,1 root=/dev/sda1 lock
This would pass the device parameter string through, and also ask the
kernel to set the root device to /dev/sda1 and save the whole command
line and reuse it for all future boots.
A sample APPEND statement is:
APPEND = "aha152x=0x340,11,3,1"
Note that the parameter string must NOT be enclosed in quotes on the
command line, but it MUST be enclosed in quotes in the APPEND
statement.
Note also that for the parameter string to be acted on, the kernel
must contain the driver for that disk type. If it does not, then there
is nothing listening for the parameter string, and you will have to
rebuild the kernel to include the required driver. For details on
rebuilding the kernel, cd to /usr/src/linux and read the README, and
read the Linux FAQ and Installation HOWTO. Alternatively you could
obtain a generic kernel for the disk type and install that.
Readers are strongly urged to read the LILO documentation before
experimenting with LILO installation. Incautious use of the "BOOT"
statement can damage partitions.
6.8. Q. How can I create an oversize ramdisk filesystem?
For kernels 1.3.48+, it is best to create a compressed filesystem as
described in Section ``Advanced Bootdisk Creation''. If your kernel is
earlier than this, you can either upgrade, or refer to version 2.0 or
below of this HOWTO.
6.9. Q. At boot time, I get error A: cannot execute B. Why?
There are several cases of program names being hardcoded in various
utilities. These cases do not occur everywhere, but they may explain
why an executable apparently cannot be found on your system even
though you can see that it is there. You can find out if a given
program has the name of another hardcoded by using the "strings"
command and piping the output through grep.
Known examples of hardcoding are:
· Shutdown in some versions has /etc/reboot hardcoded, so reboot must
be placed in the /etc directory.
· Init has caused problems for at least one person, with the kernel
being unable to find init.
To fix these problems, either move the programs to the correct
directory, or change configuration files (e.g. inittab) to point to
the correct directory. If in doubt, put programs in the same
directories as they are on your hard disk, and use the same inittab
and /etc/rc.d files as they appear on your hard disk.
6.10. Q. My kernel has ramdisk support, but initializes ramdisks of
0K
Where this occurs, a kernel message similar to:
Ramdisk driver initialized : 16 ramdisks of 0K size
appears as the kernel is booting. The size should be either the
default of 4096K, or the size specified in kernel parameters
ramdisk_size or ramdisk. If root root 5 Jul 29 21:35 vi -> elvis*
H.2. Shell Scripts to Build Diskettes
These shell scripts are provided as examples only. I use them on my
system to create rescue diskettes. You may find it convenient to use
them, but if so, read the instructions carefully - for example, if you
specify the wrong swap device, you will find your root filesystem has
been throroughly and permanently erased.... so just be darn sure you
have it correctly configured before you use it!
The upside of the scripts are that they provide a quick way to get a
rescue set together, by doing the following:
· copy a kernel to a bootdisk, and use rdev to configure it, as
explained above.
· adjust mkroot to your system and build a root disk. Use the
directory listing above as a guide to what to include.
· use mkutil to throw your favourite utilities onto one or more
utility disks.
There are two shell scripts:
· mkroot - builds a root or boot/root diskette.
· mkutil - builds a utility diskette.
Both are currently configured to run in the parent directory of
boot_disk and util_disk, each of which contains everything to be
copied to it's diskette. Note that these shell scripts will *NOT*
automatically set up and copy all the files for you - you work out
which files are needed, set up the directories and copy the files to
those directories. The shell scripts are samples which will copy the
contents of those directories. Note that they are primitive shell
scripts and are not meant for the novice user.
The scripts both contain configuration variables at the start which
allow them to be easily configured to run anywhere. First, set up the
model directories and copy all the required files into them. To see
what directories and files are needed, have a look at the sample
directory listings in the previous sections.
Check the configuration variables in the shell scripts and change them
as required before running the scripts.
H.2.1. mkroot - Make Root Diskette
______________________________________________________________________
# mkroot: make a root disk - creates a root diskette
# by building a file system on it, then mounting it and
# copying required files from a model.
# Note: the model to copy from from must dirst be set up,
# then change the configuration variables below to suit
# your system.
#
# usage: mkroot [ -d swap | ram ]
# where swap means use $SWAPDEV swap device
# and ram means use $RAMDISKDEV ramdisk device
# Copyright (c) Graham Chapman 1996. All rights reserved.
# Permission is granted for this material to be freely
# used and distributed, provided the source is acknowledged.
# No warranty of any kind is provided. You use this material
# at your own risk.
# Configuration variables - set these to suit your system
#
#### set the device to use to build the root filesystem on.
#### ramdisk is safer - swap is ok only if you have plenty of
#### free memory. If linux can't swap then things get nasty.
USEDEVICE="ramdisk" # set to either "ramdisk" or "swap"
RAMDISKDEV="/dev/ram" # ramdisk device <==== CHANGE if using ramdisk
SWAPDEV="/dev/sda7" # swap device <==== CHANGE if using swap
FSBLOCKS=3072 # desired filesystem size in blocks
#
#### set name or directory where you have set up your rootdisk
#### model
ROOTDISKDIR="./root_disk" # name of root disk directory
MOUNTPOINT="/mnt" # temporary mount point for diskette
DISKETTEDEV="/dev/fd0" # device name of diskette drive
LOGFL="`pwd`/mkroot.log" # log filename
TEMPROOTFS="/tmp/mkrootfs.gz" # temp file for compressed filesystem
# End of Configuration variables
# Internal variables
ROOTDISKDEV=
case $USEDEVICE in
swap|ramdisk) :;;
*) echo "Invalid setting for USEDEVICE variable"
exit;;
esac
clear
echo " ***************** W A R N I N G ******************
Use this script with care. If you don't understand it, then
exit NOW!"
if [ "$USEDEVICE" = "swap" ]
then
ROOTDISKDEV=$SWAPDEV
echo -e "\nThis script will temporarily remove the swap file $SWAPDEV"
echo "and use the space to build a compressed root filesystem from"
echo "the files in the directory tree below $ROOTDISKDIR. To do this"
echo "safely you must have 8Mb or more of memory, and you should"
echo "switch to single user mode via 'init 1'."
echo -e "\nIf you have used a ramdisk since the last reboot, then"
echo "reboot NOW before using this script."
echo -e "\nIf the script fails, you may not have a swap partition. Run 'free'"
echo "and check the total size to see if it is correct. If the swap"
echo "partition $SWAPDEV is missing, do the following:"
echo " umount $MOUNTPOINT"
echo " mkswap $SWAPDEV"
echo " swapon $SWAPDEV"
echo "to restore the swap partition $SWAPDEV."
else
ROOTDISKDEV=$RAMDISKDEV
echo -e "\nThis script will use a ramdisk of $FSBLOCKS Kb. To do this safely"
echo "you must have at least 8Mb of memory. If you have only 8Mb you should"
echo "ensure nothing else is running on the machine."
echo -e "\nWhen the script is complete, the ramdisk will still be present, so"
echo "you should reboot to reclaim the memory allocated to the ramdisk."
fi
echo -e "
Do you want to continue (y/n)? \c"
read ans
if [ "$ans" != "Y" -a $ans != "y" ]
then
echo "not confirmed - aborting"
exit
fi
echo "Starting mkroot at `date`" > $LOGFL
if [ "$USEDEVICE" = "swap" ]
then
echo "Unmounting swap device $SWAPDEV" | tee -a $LOGFL
swapoff $SWAPDEV >> $LOGFL 2>&1
fi
echo "Zeroing device $ROOTDISKDEV" | tee -a $LOGFL
dd if=/dev/zero of=$ROOTDISKDEV bs=1024 count=$FSBLOCKS >> $LOGFL 2>&1
if [ $? -ne 0 ]
then
echo "dd zeroing $ROOTDISKDEV failed" | tee -a $LOGFL
exit 1
fi
echo "Creating filesystem on device $ROOTDISKDEV" | tee -a $LOGFL
mke2fs -m0 $ROOTDISKDEV $FSBLOCKS >> $LOGFL 2>&1
echo "Mounting $ROOTDISKDEV filesystem at $MOUNTPOINT" | tee -a $LOGFL
mount -t ext2 $ROOTDISKDEV $MOUNTPOINT >> $LOGFL 2>&1
if [ $? -ne 0 ]
then
echo "mount failed"
exit 1
fi
# copy the directories containing files
echo "Copying files from $ROOTDISKDIR to $MOUNTPOINT" | tee -a $LOGFL
currdir=`pwd`
cd $ROOTDISKDIR
find . -print | cpio -dpumv $MOUNTPOINT >> $LOGFL 2>&1
if [ $? -ne 0 ]
then
echo "cpio step failed."
cd $currdir
exit 1
fi
cd $currdir
fssize=`du -sk $MOUNTPOINT|cut -d" " -f1`
echo "Uncompressed root filesystem size is $fssize Kb" | tee -a $LOGFL
echo "Unmounting filesystem from $ROOTDISKDEV" | tee -a $LOGFL
umount $MOUNTPOINT >> $LOGFL 2>&1
echo "Compressing filesystem from $ROOTDISKDEV into $TEMPROOTFS
This may take a few minutes..." | tee -a $LOGFL
# We don't bother with gzip -9 here - takes more than twice as long
# and saves less than 1% in space on my root disk...
dd if=$ROOTDISKDEV bs=1024 count=$FSBLOCKS 2>>$LOGFL | gzip -c > $TEMPROOTFS
fssize=`du -k $TEMPROOTFS|cut -d" " -f1`
echo "Compressed root filesystem size is $fssize Kb" | tee -a $LOGFL
echo -e "Insert diskette in $DISKETTEDEV and press any key
*** Warning: data on diskette will be overwritten!\c"
read ans
echo "Copying compressed filesystem from $TEMPROOTFS to $DISKETTEDEV" | tee -a $LOGFL
dd if=$TEMPROOTFS of=$DISKETTEDEV >>$LOGFL 2>&1
if [ $? -ne 0 ]
then
echo "copy step failed."
exit 1
fi
if [ "$USEDEVICE" = "swap" ]
then
echo "Reinitialising swap device $SWAPDEV" | tee -a $LOGFL
mkswap $SWAPDEV >> $LOGFL 2>&1
echo "Starting swapping to swap device $SWAPDEV" | tee -a $LOGFL
swapon $SWAPDEV >> $LOGFL 2>&1
fi
echo "Deleting $TEMPROOTFS" | tee -a $LOGFL
rm $TEMPROOTFS
echo "mkroot completed at `date`" >> $LOGFL
echo "Root diskette creation complete - please read log file $LOGFL"
______________________________________________________________________
H.2.2. mkutil - Make Utility Diskette
______________________________________________________________________
# mkutil: make a utility diskette - creates a utility diskette
# by building a file system on it, then mounting it and
# copying required files from a model.
# Note: the model to copy from from must first be set up,
# then change the configuration variables below to suit
# your system.
# Copyright (c) Graham Chapman 1996. All rights reserved.
# Permission is granted for this material to be freely
# used and distributed, provided the source is acknowledged.
# No warranty of any kind is provided. You use this material
# at your own risk.
# Configuration variables...
UTILDISKDIR=./util_disk # name of directory containing model
MOUNTPOINT=/mnt # temporary mount point for diskette
DISKETTEDEV=/dev/fd0 # device name of diskette drive
echo $0: create utility diskette
echo Warning: data on diskette will be overwritten!
echo Insert diskette in $DISKETTEDEV and and press any key...
read anything
mke2fs $DISKETTEDEV
if [ $? -ne 0 ]
then
echo mke2fs failed
exit
fi
# Any file system type would do here
mount -t ext2 $DISKETTEDEV $MOUNTPOINT
if [ $? -ne 0 ]
then
echo mount failed
exit
fi
# copy the directories containing files
cp -dpr $UTILDISKDIR/* $MOUNTPOINT
umount $MOUNTPOINT
echo Utility diskette complete
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