  The Linux Bootdisk HOWTO
  Graham Chapman, grahamc@zeta.org.au
  v1.02, 25 June 1995

  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.

  1.  Introduction


  1.1.  Why Build Boot Disks?

  Linux boot disks are useful in a number of situations, such as:

  o  Testing a new kernel.

  o  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 producing boot disks:

  o  Use one from a distribution such as Slackware. This will at least
     allow you to boot.

  o  Use a rescue package to set up disks designed to be used as rescue
     disks.

  o  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. Once I understood how it all worked, then I changed to using
  the Bootkit rescue package to maintain my boot disks.

  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:

  o  Linux 1.2.0

  o  LILO 0.15

  Copyright (c) Graham Chapman 1995.

  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.


  1.2.  Feedback and Credits

  I welcome any feedback, good or bad, on the content of this document.
  Please let me know if you find any errors or omissions.

  I thank the following people for correcting errors and providing
  useful suggestions for improvement:




          Randolph Bentson
          Grant R. Bowman
          Scott Burkett
          Bruce Elliot
          HARIGUCHI Youichi
          Bjxrn-Helge Mevik
          Dwight Spencer
          Cameron Spitzer
          Johannes Stille





  1.3.  Change History

  v1.02, 25 June 1995

  o  Add: FAQ question on oversize ramdisk filesystems.

  o  Add: if using mkfs, use the -i option.

  o  Add: can use cp as well as dd to copy to raw disk.

  o  Chg: correct explanation of /dev/fd0 vs /dev/fd0H1440.

  o  Chg: use "zImage" terminology to conform to standard usage.

  o  Add: mke2fs -m 0 will provide more usable disk space.

  o  Add: re-run LILO if the kernel has changed.

  o  Add: move rescue packages to new section under "References".

  o  Add: new rescue packages Bootkit and CatRescue.

  o  Add: FAQ question on cannot execute errors.

  o  Add: shell scripts are samples only - I now use Bootkit.

  o  Chg: stop using < and > in command examples - too confusing.

  o  Chg: sample directory listings are now of diskettes, not model.

  o  Chg: use more consistent terminology with ramdisks.

     v1.01, 6 February 1995

  o  Fix: DO NOT cp kernel_filename /dev/fd0 - this will overwrite any
     file system on the diskette.

  o  Fix: Put LILO boot.b and map files on target disk.

  o  Add: -dp flags to cp commands to avoid problems.

  o  Chg: restructure to try to improve readability.

  o  Add: can now use ext2 filesystem on root diskettes.

  o  Chg: can now separate boot and root diskettes.

  o  Add: credits section in Introduction.

  o  Add: FAQ.


  v1.0, 2 January 1995

  o  Converted to conform to HOWTO documentation standards.

  o  Added new section - Change History.

  o  Various minor corrections.

  v0.10, 1 November 1994 Original version, labelled "draft".


  2.  Disks


  2.1.  Summary of Disk Types

  I classify boot-related disks into 4 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.


     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.
  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:

  o  code from a boot loader such as LILO, which locates the kernel,
     loads it and executes it to start the boot proper.

  o  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:

  o  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.

  o  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 then 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:

  o  File system.

  o  Minimum set of directories - dev, proc, bin, etc, lib, usr, tmp.

  o  Basic set of utilities - bash (to run a shell), ls, cp etc.

  o  Minimum set of config files - rc, inittab, fstab etc.

  o  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:

  o  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.

  o  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 two major benefits:

  o  The system runs a lot faster.

  o  The diskette drive is freed up to allow other diskettes to be used
     on a single-diskette drive system.

  The requirements for this feature to be invoked are:

  o  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.

  o  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:

  o  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.

  o  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.

  o  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.

  o  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.

  o  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 mkfs, use the -i
  option to specify more inodes than the default; -i 2000 is suggested).

  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:

  o  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.

  o  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. 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.

  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.


  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 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:


  o  /dev is described above in the section titled DEVICES.

  o  /proc only needs to exist. Once the directory is created using
     mkdir, nothing more is required.

  o  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:

  o  Required at all times, e.g. rc, fstab, passwd.

  o  May be required, but no-one is too sure.

  o  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:

  o  The ones I must configure for a boot/root system:


               rc      system startup script
               fstab   list of file systems to be mounted
               inittab parameters for the init process - the
                       first process started at boot time.





  o  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.

  o  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 suprisingly small.

  o  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.

  o  fstab should contain:


               /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.

  In practice, a single rc file is restrictive; 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

  Two libraries are required to run many facilities under Linux:

  o  ld.so

  o  libc.so.4

  If they 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.

  These should be present in you existing /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.


  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:


  o  Which device is to be mounted as the root drive.

  o  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 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:

  o  Command line options - you can enter command line options to set
     the root device, ramdisk size, 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.

  o  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




  o  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"




  o  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.  Samples


  4.1.  Disk Directory Listings

  This lists the contents of directories from my root and utility
  diskettes. These lists are provided as an example only of the files
  included to create a working system. The disks were created using the
  Bootkit package, which copies to diskette only those files that you
  want copied.


  4.1.1.  Root Disk ls-lR Directory Listing

  The root listing is of a diskette mounted at /mnt.






  total 27
  drwx------   2 root     root         1024 Jun 11 23:23 bin/
  drwxr-xr-x   2 root     root         3072 Jun 11 23:24 dev/
  drwxr-xr-x   3 root     root         1024 May 30 06:38 etc/
  drwxr-xr-x   2 root     root         1024 Jun 11 23:24 home/
  drwxr-xr-x   2 root     root         1024 Jun 11 23:24 lib/
  drwxr-xr-x   2 root     root        12288 Jun 11 23:23 lost+found/
  drwxr-xr-x   2 root     root         1024 Jun 11 23:24 mnt/
  drwxr-xr-x   2 root     root         1024 Jun 11 23:24 proc/
  drwxr-xr-x   2 root     root         1024 May 30 05:56 root/
  drwxr-xr-x   2 root     root         1024 Jun  3 23:39 sbin/
  drwxr-xr-x   2 root     root         1024 Jun 11 23:24 tmp/
  drwxr-xr-x   3 root     root         1024 May 30 05:48 usr/
  drwxr-xr-x   2 root     root         1024 Jun 11 23:24 util/
  drwxr-xr-x   5 root     root         1024 May 30 05:58 var/

  /mnt/bin:
  total 664
  -rwxr-xr-x   1 root     root       222208 Sep  7  1992 bash*
  -rwxr-xr-x   1 root     other        4376 Sep  8  1992 cat*
  -rwxr-xr-x   1 root     other        5088 Sep  4  1992 chmod*
  -rwxr-xr-x   1 root     other        4024 Sep  4  1992 chown*
  -rwxr-xr-x   1 root     other       12104 Sep  4  1992 cp*
  -rwxr-xr-x   1 root     other        4376 Sep  5  1992 cut*
  -rwxr-xr-x   1 root     other        7592 Sep  4  1992 dd*
  -rwxr-xr-x   1 root     other        4656 Sep  4  1992 df*
  -rwxr-xr-x   1 root     root        37892 May  5  1994 e2fsck*
  -rwx--x--x   1 root     root        14396 Sep 20  1992 fdisk*
  -r-x--x--x   1 bin      bin          3536 Feb 19 19:14 hostname*
  -rwxr-xr-x   1 root     other        5292 Sep  4  1992 ln*
  -rws--x--x   1 root     root        24352 Jan 16  1993 login*
  -rwxr-xr-x   1 root     other        4104 Sep  4  1992 mkdir*
  -rwxr-xr-x   1 root     root        21508 May  5  1994 mke2fs*
  -rwxr-xr-x   1 root     other        3336 Sep  4  1992 mknod*
  -rwx--x--x   1 root     root         2432 Sep 20  1992 mkswap*
  -rwxr-xr-x   1 root     root         9596 Jun 10 22:12 mount*
  -rwxr-xr-x   1 root     other        6724 Sep  4  1992 mv*
  -rwxr-xr-x   1 root     root        11132 Apr 10  1993 ps*
  -rwxr-xr-x   1 root     other        5056 Sep  4  1992 rm*
  -rwxr-xr-x   1 root     root       222208 Sep  7  1992 sh*
  -rws--x--x   1 root     root        16464 Jan 16  1993 su*
  -rwxr-xr-x   1 root     root         1204 Sep 17  1992 sync*
  -rwxr-xr-x   1 root     root         6188 Apr 17  1993 umount*

  /mnt/dev:
  total 72
  -rwxr-xr-x   1 root     root         8331 Mar 14  1993 MAKEDEV*
  lrwxrwxrwx   1 root     root            4 Jun 11 23:24 console -> tty0
  crw-rw-rw-   1 root     tty        5,  64 Apr  1  1993 cua0
  crw-rw-rw-   1 root     tty        5,  65 Mar 19 19:35 cua1
  crw-rw-rw-   1 root     tty        5,  66 Apr 10  1993 cua2
  crw-rw-rw-   1 root     tty        5,  67 Apr 10  1993 cua3
  brw-r--r--   1 root     root       2,   0 Aug 29  1992 fd0
  brw-r--r--   1 root     root       2,  12 Aug 29  1992 fd0D360
  brw-r--r--   1 root     root       2,  16 Aug 29  1992 fd0D720
  brw-r--r--   1 root     root       2,  28 Aug 29  1992 fd0H1440
  brw-r--r--   1 root     root       2,  12 Aug 29  1992 fd0H360
  brw-r--r--   1 root     root       2,  16 Aug 29  1992 fd0H720
  brw-r--r--   1 root     root       2,   4 Aug 29  1992 fd0d360
  brw-r--r--   1 root     root       2,   8 Jan 15  1993 fd0h1200
  brw-r--r--   1 root     root       2,  20 Aug 29  1992 fd0h360
  brw-r--r--   1 root     root       2,  24 Aug 29  1992 fd0h720
  brw-r--r--   1 root     root       2,   1 Aug 29  1992 fd1
  brw-r--r--   1 root     root       2,  13 Aug 29  1992 fd1D360
  brw-r--r--   1 root     root       2,  17 Aug 29  1992 fd1D720
  brw-r--r--   1 root     root       2,  29 Aug 29  1992 fd1H1440
  brw-r--r--   1 root     root       2,  13 Aug 29  1992 fd1H360
  brw-r--r--   1 root     root       2,  17 Aug 29  1992 fd1H720
  brw-r--r--   1 root     root       2,   5 Aug 29  1992 fd1d360
  brw-r--r--   1 root     root       2,   9 Aug 29  1992 fd1h1200
  brw-r--r--   1 root     root       2,  21 Aug 29  1992 fd1h360
  brw-r--r--   1 root     root       2,  25 Aug 29  1992 fd1h720
  brw-r-----   1 root     root       3,   0 Aug 29  1992 hda
  brw-r-----   1 root     root       3,   1 Aug 29  1992 hda1
  brw-r-----   1 root     root       3,   2 Aug 29  1992 hda2
  brw-r-----   1 root     root       3,   3 Aug 29  1992 hda3
  brw-r-----   1 root     root       3,   4 Aug 29  1992 hda4
  brw-r-----   1 root     root       3,   5 Aug 29  1992 hda5
  brw-r-----   1 root     root       3,   6 Aug 29  1992 hda6
  brw-r-----   1 root     root       3,   7 Aug 29  1992 hda7
  brw-r-----   1 root     root       3,   8 Aug 29  1992 hda8
  brw-r-----   1 root     root       3,  64 Aug 29  1992 hdb
  brw-r-----   1 root     root       3,  65 Aug 29  1992 hdb1
  brw-r-----   1 root     root       3,  66 Aug 29  1992 hdb2
  brw-r-----   1 root     root       3,  67 Aug 29  1992 hdb3
  brw-r-----   1 root     root       3,  68 Aug 29  1992 hdb4
  brw-r-----   1 root     root       3,  69 Aug 29  1992 hdb5
  brw-r-----   1 root     root       3,  70 Aug 29  1992 hdb6
  brw-r-----   1 root     root       3,  71 Aug 29  1992 hdb7
  brw-r-----   1 root     root       3,  72 Aug 29  1992 hdb8
  crw-r-----   1 root     kmem       1,   2 Aug 29  1992 kmem
  crw-rw-rw-   1 root     root       6,   0 Aug 29  1992 lp0
  crw-rw-rw-   1 root     root       6,   1 Aug 29  1992 lp1
  crw-rw-rw-   1 root     root       6,   2 Aug 29  1992 lp2
  crw-r-----   1 root     sys        1,   1 Aug 29  1992 mem
  lrwxrwxrwx   1 root     root            4 Jun 11 23:24 mouse -> cua1
  crw-rw-rw-   1 root     root      27,   4 Jul 31  1994 nrft0
  crw-rw-rw-   1 root     root      27,   5 Jul 31  1994 nrft1
  crw-rw-rw-   1 root     root      27,   6 Jul 31  1994 nrft2
  crw-rw-rw-   1 root     root      27,   7 Jul 31  1994 nrft3
  crw-------   1 root     root       9, 128 Jan 23  1993 nrmt0
  crw-rw-rw-   1 root     root       1,   3 Aug 29  1992 null
  crw-r-----   1 root     root       6,   0 Aug 29  1992 par0
  crw-r-----   1 root     root       6,   1 Aug 29  1992 par1
  crw-r-----   1 root     root       6,   2 Aug 29  1992 par2
  crw-r-----   1 root     root       1,   4 Aug 29  1992 port
  crw-rw-rw-   1 root     root       4, 128 Jun 10 00:10 ptyp0
  crw-rw-rw-   1 root     root       4, 129 Apr 10 14:51 ptyp1
  crw-rw-rw-   1 root     root       4, 130 Aug 21  1994 ptyp2
  crw-rw-rw-   1 root     root       4, 131 Apr 12  1993 ptyp3
  crw-rw-rw-   1 root     tty        4, 132 Jan  3  1993 ptyp4
  crw-rw-rw-   1 root     tty        4, 133 Jan  3  1993 ptyp5
  crw-rw-rw-   1 root     tty        4, 134 Jan  3  1993 ptyp6
  crw-rw-rw-   1 root     tty        4, 135 Jan  3  1993 ptyp7
  crw-rw-rw-   1 root     tty        4, 136 Jan  3  1993 ptyp8
  crw-rw-rw-   1 root     tty        4, 137 Jan  3  1993 ptyp9
  crw-rw-rw-   1 root     tty        4, 138 Jan  3  1993 ptypa
  crw-rw-rw-   1 root     tty        4, 139 Jan  3  1993 ptypb
  crw-rw-rw-   1 root     tty        4, 140 Jan  3  1993 ptypc
  crw-rw-rw-   1 root     tty        4, 141 Jan  3  1993 ptypd
  crw-rw-rw-   1 root     tty        4, 142 Jan  3  1993 ptype
  crw-rw-rw-   1 root     tty        4, 143 Jan  3  1993 ptypf
  brw-rw----   1 root     root       1,   0 Jun  8 18:49 ram
  crw-rw-rw-   1 root     root      27,   0 Jul 31  1994 rft0
  crw-rw-rw-   1 root     root      27,   1 Jul 31  1994 rft1
  crw-rw-rw-   1 root     root      27,   2 Jul 31  1994 rft2
  crw-rw-rw-   1 root     root      27,   3 Jul 31  1994 rft3
  crw-------   1 root     root       9,   0 Jan 23  1993 rmt0
  brw-r-----   1 root     root       8,   0 Aug 29  1992 sda
  brw-r-----   1 root     root       8,   1 Aug 29  1992 sda1
  brw-r-----   1 root     root       8,   2 Aug 29  1992 sda2
  brw-r-----   1 root     root       8,   3 Aug 29  1992 sda3
  brw-r-----   1 root     root       8,   4 Aug 29  1992 sda4
  brw-r-----   1 root     root       8,   5 Aug 29  1992 sda5
  brw-r-----   1 root     root       8,   6 Aug 29  1992 sda6
  brw-r-----   1 root     root       8,   7 Aug 29  1992 sda7
  brw-r-----   1 root     root       8,   8 Aug 29  1992 sda8
  brw-r-----   1 root     root       8,  16 Aug 29  1992 sdb
  brw-r-----   1 root     root       8,  17 Aug 29  1992 sdb1
  brw-r-----   1 root     root       8,  18 Aug 29  1992 sdb2
  brw-r-----   1 root     root       8,  19 Aug 29  1992 sdb3
  brw-r-----   1 root     root       8,  20 Aug 29  1992 sdb4
  brw-r-----   1 root     root       8,  21 Aug 29  1992 sdb5
  brw-r-----   1 root     root       8,  22 Aug 29  1992 sdb6
  brw-r-----   1 root     root       8,  23 Aug 29  1992 sdb7
  brw-r-----   1 root     root       8,  24 Aug 29  1992 sdb8
  brw-------   1 bin      bin        8,  32 Jun 30  1992 sdc
  brw-------   1 bin      bin        8,  33 Jun 30  1992 sdc1
  brw-------   1 bin      bin        8,  34 Jun 30  1992 sdc2
  brw-------   1 bin      bin        8,  35 Jun 30  1992 sdc3
  brw-------   1 bin      bin        8,  36 Jun 30  1992 sdc4
  brw-------   1 bin      bin        8,  37 Jun 30  1992 sdc5
  brw-------   1 bin      bin        8,  38 Jun 30  1992 sdc6
  brw-------   1 bin      bin        8,  39 Jun 30  1992 sdc7
  brw-------   1 bin      bin        8,  40 Jun 30  1992 sdc8
  brw-------   1 bin      bin        8,  48 Jun 30  1992 sdd
  brw-------   1 bin      bin        8,  49 Jun 30  1992 sdd1
  brw-------   1 bin      bin        8,  50 Jun 30  1992 sdd2
  brw-------   1 bin      bin        8,  51 Jun 30  1992 sdd3
  brw-------   1 bin      bin        8,  52 Jun 30  1992 sdd4
  brw-------   1 bin      bin        8,  53 Jun 30  1992 sdd5
  brw-------   1 bin      bin        8,  54 Jun 30  1992 sdd6
  brw-------   1 bin      bin        8,  55 Jun 30  1992 sdd7
  brw-------   1 bin      bin        8,  56 Jun 30  1992 sdd8
  brw-------   1 bin      bin        8,  64 Jun 30  1992 sde
  brw-------   1 bin      bin        8,  65 Jun 30  1992 sde1
  brw-------   1 bin      bin        8,  66 Jun 30  1992 sde2
  brw-------   1 bin      bin        8,  67 Jun 30  1992 sde3
  brw-------   1 bin      bin        8,  68 Jun 30  1992 sde4
  brw-------   1 bin      bin        8,  69 Jun 30  1992 sde5
  brw-------   1 bin      bin        8,  70 Jun 30  1992 sde6
  brw-------   1 bin      bin        8,  71 Jun 30  1992 sde7
  brw-------   1 bin      bin        8,  72 Jun 30  1992 sde8
  crw-rw-rw-   1 root     root       5,   0 Apr 16  1994 tty
  crw-rw-rw-   1 grahamc  other      4,   0 Jun 11 23:21 tty0
  crw--w--w-   1 root     root       4,   1 Jun 11 23:23 tty1
  crw-rw-rw-   1 root     root       4,   2 Jun 11 23:21 tty2
  crw-rw-rw-   1 root     root       4,   3 Jun 11 23:21 tty3
  crw-rw-rw-   1 root     other      4,   4 Jun 11 23:21 tty4
  crw-rw-rw-   1 root     other      4,   5 Jun 11 23:21 tty5
  crw-rw-rw-   1 root     root       4,   6 Jun 11 23:21 tty6
  crw--w--w-   1 grahamc  other      4,   7 Apr 15  1993 tty7
  crw--w--w-   1 root     root       4,   8 Apr 15  1993 tty8
  crw-rw-rw-   1 root     root       4,  64 Mar 30  1993 ttyS0
  crw-rw-rw-   1 root     users      4,  65 Mar 31  1993 ttyS1
  crw-rw-rw-   1 root     root       4,  66 Jan 23  1980 ttyS2
  crw-rw-rw-   1 root     root       4, 192 Jun 10 00:10 ttyp0
  crw-rw-rw-   1 root     root       4, 193 Apr 10 14:51 ttyp1
  crw-rw-rw-   1 root     root       4, 194 Aug 21  1994 ttyp2
  crw-rw-rw-   1 root     root       4, 195 Apr 12  1993 ttyp3
  crw-rw-rw-   1 root     tty        4, 196 Jan  3  1993 ttyp4
  crw-rw-rw-   1 root     tty        4, 197 Jan  3  1993 ttyp5
  crw-rw-rw-   1 root     tty        4, 198 Jan  3  1993 ttyp6
  crw-rw-rw-   1 root     tty        4, 199 Jan  3  1993 ttyp7
  crw-rw-rw-   1 root     tty        4, 200 Jan  3  1993 ttyp8
  crw-rw-rw-   1 root     tty        4, 201 Jan  3  1993 ttyp9
  crw-rw-rw-   1 root     tty        4, 202 Jan  3  1993 ttypa
  crw-rw-rw-   1 root     tty        4, 203 Jan  3  1993 ttypb
  crw-rw-rw-   1 root     tty        4, 204 Jan  3  1993 ttypc
  crw-rw-rw-   1 root     tty        4, 205 Jan  3  1993 ttypd
  crw-rw-rw-   1 root     tty        4, 206 Jan  3  1993 ttype
  crw-rw-rw-   1 root     tty        4, 207 Jan  3  1993 ttypf
  -rw-------   1 root     root        63488 Mar 14  1993 ttys0
  crw-rw-rw-   1 root     root       4,  67 Oct 14  1992 ttys3
  crw-r--r--   1 root     root       1,   5 Aug 29  1992 zero

  /mnt/etc:
  total 108
  -rw-r--r--   1 root     root           94 May 30 06:15 fstab
  -rwx------   1 root     root        25604 Mar 17  1993 getty*
  -rw-------   1 root     root          566 Dec 30  1992 gettydefs
  -rw-rw-r--   1 root     shadow        321 Oct  3  1994 group
  -rwxr-xr-x   1 bin      bin          9220 Mar 17  1993 halt*
  -rw-r--r--   1 root     root           26 Feb 19 19:07 host.conf
  -rw-r--r--   1 root     root          506 Feb 19 19:07 hosts
  -rwxr-xr-x   1 bin      bin         17412 Mar 17  1993 init*
  -rw-r--r--   1 root     root         1354 Jun  3 23:42 inittab
  -rwxr-xr-x   1 root     root         1478 Mar 17 18:29 issue*
  -rw-rw----   1 root     shadow       5137 Dec  4  1992 login.defs
  -rw-r--r--   1 sysadmin bin            42 Mar 17 18:30 motd
  -rw-r--r--   1 root     shadow        525 Jun 11 23:24 passwd
  -rwxr-xr-x   1 root     root         1476 Aug 17  1994 profile*
  -rw-r--r--   1 root     root          715 Feb 19 19:02 protocols
  drwxr-xr-x   2 root     root         1024 May 30 06:05 rc.d/
  -rwxr-xr-x   1 bin      bin          9220 Mar 17  1993 reboot*
  -r--r--r--   1 bin      bin            57 Nov 28  1992 securetty
  -rw-r--r--   1 root     root         3316 Feb 19 19:01 services
  -rwxr-xr-x   1 bin      bin         13316 Mar 17  1993 shutdown*
  -rwxr-xr-x   1 root     root         3212 Apr 17  1993 swapoff*
  -rwxr-xr-x   1 root     root         3212 Apr 17  1993 swapon*
  -rw-r--r--   1 root     root          817 Jun 11 23:23 termcap
  -rwxr-xr-x   1 root     root         6188 Apr 17  1993 umount*
  -rw-r--r--   1 root     root        12264 Jun 11 23:22 utmp
  -rw-r--r--   1 root     root           56 Jun 11 23:22 wtmp

  /mnt/etc/rc.d:
  total 4
  -rwxr-xr--   1 root     root          450 May 30 06:05 rc.0*
  -rwxr-xr--   1 root     root          390 May 30 06:05 rc.K*
  -rwxr-xr--   1 root     root          683 May 30 06:06 rc.M*
  -rwxr-xr--   1 root     root          498 Jun 11 18:44 rc.S*

  /mnt/home:
  total 0

  /mnt/lib:
  total 287
  -rwxr-xr-x   1 root     root        17412 Jun 11 23:24 ld.so*
  lrwxrwxrwx   1 root     root           14 Jun 11 23:24 libc.so.4 -> libc.so.4.5.21*
  -rwxr-xr-x   1 root     root       623620 May 22  1994 libc.so.4.5.21*

  /mnt/lost+found:
  total 0

  /mnt/mnt:
  total 0

  /mnt/proc:
  total 0

  /mnt/root:
  total 0

  /mnt/sbin:
  total 15
  -rwxr-xr-x   1 root     root        16885 Jun 13  1994 update*

  /mnt/tmp:
  total 0

  /mnt/usr:
  total 1
  drwxr-xr-x   2 root     root         1024 May 30 05:49 bin/

  /mnt/usr/bin:
  total 217
  -rwxr-xr-x   1 root     root         1560 Sep 17  1992 basename*
  -rws--x--x   1 root     root         8232 Jan 16  1993 chsh*
  -rwxr-xr-x   1 root     root         1308 Jan 23  1980 clear*
  -rwxr-xr-x   1 root     other       91136 Sep  4  1992 elvis*
  -rwxr-xr-x   1 root     root        13252 Sep 17  1992 ls*
  -rwxr-xr-x   1 bin      bin         21504 Oct  2  1992 more*
  -rwxr-xr-x   1 root     other       91136 Sep  4  1992 vi*

  /mnt/util:
  total 0

  /mnt/var:
  total 3
  drwxr-xr-x   2 root     root         1024 May 30 05:58 adm/
  drwxr-xr-x   2 root     root         1024 Jun 11 23:24 logs/
  drwxr-xr-x   2 root     root         1024 Jun 11 23:24 run/

  /mnt/var/adm:
  total 0
  -rw-r--r--   1 root     root            0 May 30 05:58 utmp
  -rw-r--r--   1 root     root            0 May 30 05:58 wtmp

  /mnt/var/logs:
  total 0

  /mnt/var/run:
  total 0





  4.1.2.  Utility Disk ls-lR Directory Listing

  The utility listing is of a diskette mounted at /mnt.



















  total 15
  drwx------   2 root     root         1024 Jun 18 19:57 bin/
  drwxr-xr-x   2 root     root        12288 Jun 18 19:57 lost+found/
  drwx------   2 root     root         1024 Jun 18 19:57 sbin/
  drwxr-xr-x   4 root     root         1024 May  5 16:30 usr/

  /mnt/bin:
  total 13
  -rwxr-xr-x   1 root     root         3180 Apr 10  1993 free*
  -rwxr-xr-x   1 root     root        10687 Feb 10  1994 pwd*
  -rwx--x--x   1 root     root         3672 Nov 17  1992 rdev*

  /mnt/lost+found:
  total 0

  /mnt/sbin:
  total 18
  -rwxr-xr-x   1 root     root        16336 Jun 18 14:31 insmod*
  -rwxr-xr-x   1 root     root           68 Jun 18 14:31 lsmod*
  lrwxrwxrwx   1 root     root            6 Jun 18 19:57 rmmod -> insmod*

  /mnt/usr:
  total 2
  drwx------   2 root     root         1024 Jun 18 19:57 bin/
  drwxr-xr-x   3 root     root         1024 Jun 18 19:57 local/

  /mnt/usr/bin:
  total 411
  -rwxr-xr-x   1 root     bin        111616 Sep  9  1992 awk*
  -rwxr-xr-x   1 root     root        41984 Dec 23  1992 cpio*
  -rwxr-xr-x   1 root     root        50176 Dec 23  1992 find*
  -rwxr-xr-x   1 root     root       115712 Sep 17  1992 gawk*
  -rwxr-xr-x   1 root     bin         37888 Sep  4  1992 grep*
  -rwxr-xr-x   1 root     root        63874 May  1  1994 gzip*
  -rwxr-xr-x   1 root     root         2044 Sep 17  1992 kill*
  -rwx--x--x   1 root     root         3132 Jan 24  1993 mt*
  -rwxr-xr-x   1 root     root         3416 Sep 22  1992 strings*
  -rwxr-xr-x   1 root     other        3848 Sep  4  1992 who*

  /mnt/usr/local:
  total 1
  drwx------   2 root     root         1024 Jun 18 19:57 bin/

  /mnt/usr/local/bin:
  total 374
  -rwxr-xr-x   1 root     root       155542 Jun 18 17:07 ftape.o*
  -rwxr-xr-x   1 root     root       226308 Jun 13  1994 tar*





  4.2.  Shell Scripts to Build Diskettes

  These shell scripts are provided as examples only. I no longer use
  them because I now use and recommend Scott Burkett's Bootkit package
  to manage rescue diskette contents and creation. Bootkit is based on
  these scripts, and does essentially the same thing, but it is much
  tidier, nicer and easier to use. However, the sample shell scripts
  here will still provide working diskettes.

  There are two shell scripts:

  o  mkroot - builds a root or boot/root diskette.


  o  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.


  4.2.1.  mkroot - Make Root or Boot/Root Diskette












































  ______________________________________________________________________
  # mkroot: make a boot/boot disk - creates a boot/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 [nokernel]
  #       if the parameter is omitted, then the kernel and LILO
  #       are copied.

  # Copyright (c) Graham Chapman 1995. 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...
  BOOTDISKDIR=./boot_disk       # name of boot disk directory
  MOUNTPOINT=./mnt              # temporary mount point for diskette
  LILODIR=/sbin                 # directory containing lilo
  LILOBOOT=/boot/boot.b         # lilo boot sector
  LILOMSG=./lilo.msg            # lilo message to display at boot time
  LILOCONFIG=./lilo.conf        # lilo parms for boot/root diskette
  DISKETTEDEV=/dev/fd0          # device name of diskette drive

  echo $0: create boot/root 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

  mount -t ext2 $DISKETTEDEV $MOUNTPOINT
  if [ $? -ne 0 ]
  then
          echo mount failed
          exit
  fi

  # copy the directories containing files
  for i in bin etc lib
  do
          cp -dpr $BOOTDISKDIR/$i $MOUNTPOINT
  done

  # copy dev *without* trying to copy the files in it
  cp -dpR $BOOTDISKDIR/dev $MOUNTPOINT

  # create empty directories required
  mkdir $MOUNTPOINT/proc
  mkdir $MOUNTPOINT/tmp
  mkdir $MOUNTPOINT/mnt
  mkdir $MOUNTPOINT/usr

  # copy the kernel
  if [ "$1" != "nokernel" ]
  then
          echo "Copying kernel"
          cp $BOOTDISKDIR/zImage $MOUNTPOINT
          echo kernel copied

          # setup lilo
          cp $LILOBOOT $MOUNTPOINT
          cp $LILOMSG $MOUNTPOINT
          $LILODIR/lilo -C $LILOCONFIG
          echo LILO installed
  fi

  umount $MOUNTPOINT

  echo Root diskette complete
  ______________________________________________________________________





  4.2.2.  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 1995. 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/bin $MOUNTPOINT

  umount $MOUNTPOINT

  echo Utility diskette complete
  ______________________________________________________________________





  5.  FAQ


  5.1.  Q. How can I make a boot disk with a XXX driver?

  The easiest way is to obtain a Slackware kernel from your nearest
  Slackware mirror site. Slackware kernels are generic kernels which
  atttempt to include drivers for as many devices as possible, so if you
  have a SCSI or IDE controller, chances are that a driver for it is
  included in the Slackware kernel.

  Go to the a1 directory and select either IDE or SCSI kernel depending
  on the type of controller you have. Check the xxxxkern.cfg file for
  the selected kernel to see the drivers which have been included in
  that kernel. If the device you want is in that list, then the
  corresponding kernel should boot your computer. Download the
  xxxxkern.tgz file and copy it to your boot diskette as described above
  in the section on making boot disks.

  You must then check the root device in the kernel, using the rdev
  command:


               rdev zImage




  Rdev will then display the current root device in the kernel. If this
  is not the same as the root device you want, then use rdev to change
  it.  For example, the kernel I tried was set to /dev/sda2, but my root
  scsi partition is /dev/sda8. To use a root diskette, you would have to
  use the command:


               rdev zImage /dev/fd0




  If you want to know how to set up a Slackware root disk as well,
  that's outside the scope of this HOWTO, so I suggest you check the
  Linux Install Guide or get the Slackware distribution. See the section
  in this HOWTO titled "References".


  5.2.  Q. How do I update my boot floppy with a new kernel?

  Just copy the kernel to your boot diskette using the dd command for a
  boot diskette without a filesystem, or the cp command for a boot/root
  disk. Refer to the section in this HOWTO titled "Boot" for details on
  creating a boot disk. The description applies equally to updating a
  kernel on a boot disk.


  5.3.  Q. How do I remove LILO so that I can use DOS to boot again?

  This is not really a Bootdisk topic, but it is asked so often, so: the
  answer is, use the DOS command:


               FDISK /MBR




  MBR stands for Master Boot Record, and it replaces the boot sector
  with a clean DOS one, without affecting the partition table. Some
  purists disagree with this, but even the author of LILO, Werner
  Almesberger, suggests it. It is easy, and it works.

  You can also use the dd command to copy the backup saved by LILO to
  the boot sector - refer to the LILO documentation if you wish to do
  this.


  5.4.  Q. How can I boot if I've lost my kernel AND my boot disk?

  If you don't have a boot disk standing by, then probably the easiest
  method is to obtain a Slackware kernel for your disk controller type
  (IDE or SCSI) as described above for "How do I make a boot disk with a
  XXX driver?". You can then boot your computer using this kernel, then
  repair whatever damage there is.

  The kernel you get may not have the root device set to the disk type
  and partition you want. For example, Slackware's generic scsi kernel
  has the root device set to /dev/sda2, whereas my root Linux partition
  happens to be /dev/sda8. In this case the root device in the kernel
  will have to be changed.

  You can still change the root device and ramdisk settings in the
  kernel even if all you have is a kernel, and some other operating
  system, such as DOS.

  Rdev changes kernel settings by changing the values at fixed offsets
  in the kernel file, so you can do the same if you have a hex editor
  available on whatever systems you do still have running - for example,
  Norton Utilities Disk Editor under DOS.  You then need to check and if
  necessary change the values in the kernel at the following offsets:


       0x01F8  Low byte of RAMDISK size
       0x01F9  High byte of RAMDISK size
       0x01FC  Root minor device number - see below
       0X01FD  Root major device number - see below




  The ramdisk size is the number of blocks of ramdisk to create.  If you
  want to boot from a root diskette then set this to decimal 1440, which
  is 0x05A0, thus set offset 0x01F8 to 0xA0 and offset 0x01F9 to 0x05.
  This will allocate enough space for a 1.4Mb diskette.

  The major and minor device numbers must be set to the device you want
  to mount your root filesystem on. Some useful values to select from
  are:


       device          major minor
       /dev/fd0            2     0   1st floppy drive
       /dev/hda1           3     1   partition 1 on 1st IDE drive
       /dev/sda1           8     1   partition 1 on 1st scsi drive
       /dev/sda8           8     8   partition 8 on 1st scsi drive




  Once you 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.


  5.5.  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





  5.6.  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:

  o  By entering it on the command line every time the system is booted
     via LILO. This is boring, though.

  o  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.

  o  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.


  5.7.  Q. How can I create an oversize ramdisk filesystem?

  An oversize ramdisk filesystem is a filesystem in a ramdisk larger
  than the size of the root disk it was loaded from. This can be
  extremely useful when using Ftape, which requires exclusive use of the
  floppy disk controller (see the Ftape HOWTO for details.)

  Two things are required: create an oversize file system on the root
  diskette, and then patch the kernel so that it will not try to load
  blocks off the end of the diskette.

  To create an oversize filesystem, two methods are possible:

  o  Use the "blocks" e2fsck parameter to specify the size of filesystem
     that you eventually want in the ramdisk. For example:


               mke2fs /dev/fd0 3000




  will create a filesystem on the diskette of 3000 1Kb blocks. The
  diskette only has 1440 blocks, but mke2fs does not care about this.
  E2fs will care about it if you try to use more than 1440 blocks of
  data (allowing for blocks used as inodes and reserved etc), but up to
  this point it is quite safe. You will soon find out if you try to load
  too much on the diskette because an I/O error will result.

  o  Create a partition on your hard disk as large as the filesystem you
     want on the ramdisk. Then create a filesystem on it and load in the
     files you want. Then use dd to copy only the first 1440 blocks to
     diskette, and then check that there was nothing in the uncopied
     part of the filesystem. For example:


               dd if=/dev/hdb of=/dev/fd0 bs=1024 count=1440
               dd if=/dev/hdb of=tailpart bs=1024 skip=1440
               cmp -l tailparm /dev/zero




  Of the two, I prefer the first method - it appears easier and safer.

  The second thing required to get an oversized filesystem is to get the
  kernel to stop loading at the end of the physical diskette when it
  tries to load the root diskette into ramdisk. To do this, a simple
  patch can be applied to the ramdisk driver, which should be found in
  /usr/src/linux/drivers/block/ramdisk.c. The following patch has been
  contributed by Bruce Elliot. It is for kernel version 1.2.0, but it
  should be fairly easy to apply to later versions. Even if the patch
  will not apply, the code is not complex, so the patch could easily be
  modified until it worked.



































  =================================================================
  X--- ramdisk.c~ Mon Jan 23 13:04:09 1995
  X+++ ramdisk.c  Mon May 29 00:54:52 1995
  X@@ -113,6 +113,7 @@
  X               (struct ext2_super_block *)&sb;
  X       int             block, tries;
  X       int             i = 1;
  X+      int             fblocks;
  X       int             nblocks;
  X       char            *cp;
  X
  X@@ -168,12 +169,16 @@
  X                                       nblocks, rd_length >> BLOCK_SIZE_BITS);
  X                       return;
  X               }
  X-              printk("RAMDISK: Loading %d blocks into RAM disk", nblocks);
  X+              fblocks = blk_size[MAJOR(ROOT_DEV)][MINOR(ROOT_DEV)];
  X+              if (fblocks > nblocks)
  X+                      fblocks = nblocks;
  X+              printk("RAMDISK: Loading %d blocks into %d block filesystem "
  X+                                      "in RAM disk", fblocks, nblocks);
  X
  X               /* We found an image file system.  Load it into core! */
  X               cp = rd_start;
  X-              while (nblocks) {
  X-                      if (nblocks > 2)
  X+              while (fblocks) {
  X+                      if (fblocks > 2)
  X                               bh = breada(ROOT_DEV, block, BLOCK_SIZE, 0,  PAGE_SIZE);
  X                       else
  X                               bh = bread(ROOT_DEV, block, BLOCK_SIZE);
  X@@ -184,7 +189,7 @@
  X                       }
  X                       (void) memcpy(cp, bh->b_data, BLOCK_SIZE);
  X                       brelse(bh);
  X-                      if (!(nblocks-- & 15)) printk(".");
  X+                      if (!(fblocks-- & 15)) printk(".");
  X                       cp += BLOCK_SIZE;
  X                       block++;
  X                       i++;
  =================================================================




  With this patch, the kernel stops loading at the end of the physical
  diskette, leaving a filesystem larger than the disk.

  Some warnings: I have been able to create stable ramdisk filesystems
  in this fashion of 3500 blocks, but if I try 3600 or more then the
  kernel collapses with an error something like "fixup table corrupt".
  I have not been able to track down why, but obviously something is
  overflowing. Up to 3500 blocks, though, I have had no problems.


  5.8.  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:

  o  Shutdown in some versions has /etc/reboot hardcoded, so reboot must
     be placed in the /etc directory.

  o  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.  References

  In this section, vvv is used in package names in place of the version,
  to avoid referring here to specific versions. When retrieving a
  package, always get the latest version unless you have good reasons
  for not doing so.


  6.1.  LILO - Linux Loader

  Written by Werner Almesberger. Excellent boot loader, and the
  documentation includes information on the boot sector contents and the
  early stages of the boot process.

  Ftp from: tsx-11.mit.edu: /pub/linux/packages/lilo/lilo.vvv.tar.gz
  also on sunsite and mirror sites.


  6.2.  Linux FAQ and HOWTOs

  These are available from many sources. Look at the usenet newsgroups
  news.answers and comp.os.linux.announce.

  Ftp from: sunsite.unc.edu:/pub/Linux/docs

  o  FAQ is in /pub/linux/docs/faqs/linux-faq

  o  HOWTOs are in /pub/Linux/docs/HOWTO

  For WWW, start at the Linux documentation home page:


       http://sunsite.unc.edu/mdw/linux.html




  If desperate, send mail to:


               mail-server@rtfm.mit.edu




  with the word "help" in the message, then follow the mailed
  instructions.

  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.


  6.3.  Rescue Packages


  6.3.1.  Bootkit

  Written by Scott Burkett. Bootkit provides a flexible menu-driven
  framework for managing rescue disk creation and contents. It uses the
  Dialog package to provide nice menus, and a straight-forward directory
  tree to contain definitions of rescue disk contents. The package
  includes samples of the main files needed. The package aims to provide
  only the framework; it is up to the user to work out what to put on
  the disks and set up the config files accordingly.  For those users
  who don't mind doing this, it is a good choice.  I use this package
  myself.

  Ftp from: sunsite.unc.edu: /pub/Linux/system/Recovery/Bootkit-
  vvv.tar.gz


  6.3.2.  CatRescue

  Written by Oleg Kibirev. This package concentrates on saving space on
  the rescue diskettes by extensive use of compression, and by
  implementing executables as shells scripts. The doco includes some
  tips on what to do in various disaster situations.

  Ftp from: gd.cs.csufresno.edu/pub/sun4bin/src/CatRescue100.tgz


  6.3.3.  Rescue Shell Scripts

  Written by Thomas Heiling. This contains shell scripts to produce boot
  and boot/root diskettes. It has some dependencies on specific versions
  of other software such as LILO, and so might need some effort to
  convert to your system, but it might be useful as a starting point if
  you wanted more comprehensive shell scripts than are provided in this
  document.

  Ftp from: sunsite.unc.edu:/pub/Linux/system/Recovery/rescue.tgz


  6.3.4.  SAR - Search and Rescue

  Written by Karel Kubat. SAR produces a rescue diskette, using several
  techniques to minimize the space required on the diskette.  The manual
  includes a description of the Linux boot/login process.

  Ftp from: ftp.icce.rug.nl:/pub/unix/SAR-vvv.tar.gz

  The manual is available via WWW from:

  http://www.icce.rug.nl/karel/programs/SAR.html


  6.4.  Slackware Distribution

  Apart from being one of the more popular Linux distributions around,
  it is also a good place to get a generic kernel. It is available from
  almost everywhere, so there is little point in putting addresses here.
