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The Linux Bootdisk HOWTO Graham Chapman, grahamc@zeta.org.au v1.01, 6 February 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 choose 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: o Linux 1.1.73 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 Bjxrn-Helge Mevik Johannes Stille 1.3. Change History v1.01, 6 February 1995 o Fix: DO NOT cp <kernel file> /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 following 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 = <device> 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 <device>. o By running the rdev utility: rdev <filename> <device> This will set the root device of the kernel contained in <filename> to be <device>. For example: rdev Image /dev/sda1 This sets the root device in the kernel in Image to the first parti- tion on the first SCSI drive. There are some alternative ways of issuing the rdev command. Try: rdev -? 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 never hurts to check, though. To use rdev to check the current root device in a kernel file, enter the command: rdev -r <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. If the disk is not intended to contain a file system, then the kernel must be copied using the dd command, as follows: dd if=<filename> of=<device> where <filename> is the name of the kernel and <device> is the diskette raw device, usually /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 varies. Many systems have /dev/fd0 as an alias of one sort or another for the "real" device name for the default diskette drive. For example, where the default drive (i.e. "drive A:" in DOS) is a high density 3 1/2 inch diskette drive, the device name will be /dev/fd0H1440, but usually /dev/fd0 points to the same device. 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 Image /mnt umount /mnt 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 Drives and Root Filesystems on Diskette For a diskette root filesystem to be efficient, you need to be able to run it from a ramdrive, 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. There is an added benefit from using a ramdrive - 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 RAM disk, and then switch the root drive to be the RAM disk 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 below 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 RAM disk must be configured into the kernel, and it must be at least as big as the diskette drive. A RAM disk 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 Image, enter: rdev -r Image 1440 this might change in the future, of course. To see what your version of rdev does, enter the command: rdev -? 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 RAM drive 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: vmlinux 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. 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 above in the section titled "File Systems" above. 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. To create an ext2 file system on a diskette on my system, I issue the following command: mke2fs /dev/fd0 The mke2fs command will automatically detect the space available and configure itself accordingly. It does not therefore require any parameters. 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. Note, though, that the Ftape module (or at least the one I have) is quite large and will not fit on your boot/root diskette. You will need to put it on a utility diskette - this is described below in the section titled "ADDING UTILITY DISKETTES". 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. 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. 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. 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 (possibly the only 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/vmlinux 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 RAM disk 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 DRIVES 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: vmlinux [ 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. 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, ramdrive 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: vmlinux 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: vmlinux 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 files and directories that I keep on my hard disk to use when building boot/root and utility diskettes. It shows which files I put in the /etc and /bin directories on my diskettes. The sample shell scripts in the next section use these directories and files as a model to build the diskettes. 4.1.1. Boot/Root Disk ls-lR Directory Listing The boot/root listing is of directory boot_disk: total 226 drwxr-xr-x 2 root root 1024 Oct 8 13:40 bin/ drwxr-xr-x 2 root root 3072 Sep 8 16:37 dev/ drwxr-xr-x 2 root root 1024 Oct 8 12:38 etc/ drwxr-xr-x 2 root root 1024 Sep 10 14:58 lib/ -rw-r--r-- 1 root root 297956 Jan 25 21:55 vmlinux boot_disk/bin: total 366 -rwxr-xr-x 1 root root 4376 Sep 9 21:34 cat* -rwxr-xr-x 1 root root 4112 Sep 9 21:34 chown* -rwxr-xr-x 1 root root 12148 Sep 9 21:34 cp* -rwxr-xr-x 1 root root 4376 Sep 9 21:34 cut* -rwxr-xr-x 1 root root 7660 Sep 9 21:34 dd* -rwxr-xr-x 1 root root 4696 Sep 9 21:34 df* -rwx--x--x 1 root root 1392 Sep 10 14:13 hostname* -rwxr-xr-x 1 root root 5252 Sep 9 21:34 ln* -rwsr-xr-x 1 root root 6636 Sep 9 21:34 login* -rwxr-xr-x 1 root root 13252 Sep 9 21:34 ls* -rwxr-xr-x 1 root root 4104 Sep 9 21:34 mkdir* -rwxr-xr-x 1 root root 21504 Sep 10 15:27 more* -rwxr-xr-x 1 root root 6744 Sep 9 21:34 mv* -rwxr-xr-x 1 root root 9780 Sep 9 21:34 ps* -rwxr-xr-x 1 root root 5076 Sep 9 21:34 rm* -r-xr-xr-x 1 root root 12604 Sep 9 21:34 sed* -rwxr-xr-x 1 root root 222208 Sep 9 21:34 sh* -rws--x--x 1 root root 16464 Sep 9 21:34 su* -rwxr-xr-x 1 root root 1216 Sep 9 21:34 sync* boot_disk/dev: total 73 -rwxr-xr-x 1 root root 8331 Sep 8 16:31 MAKEDEV* crw-r--r-- 1 root root 10, 3 Sep 8 16:31 bmouseatixl crw-r--r-- 1 root root 10, 0 Sep 8 16:31 bmouselogitec crw-r--r-- 1 root root 10, 2 Sep 8 16:31 bmousems crw-r--r-- 1 root root 10, 1 Sep 8 16:31 bmouseps2 crw------- 1 root root 0, 0 Sep 8 16:31 boot0 crw-r--r-- 1 root root 4, 0 Sep 8 16:31 console crw-r--r-- 1 root root 5, 64 Sep 8 16:31 cua0 crw-r--r-- 1 root root 5, 65 Sep 8 16:31 cua1 crw-r--r-- 1 root root 5, 66 Sep 8 16:31 cua2 crw-r--r-- 1 root root 5, 67 Sep 8 16:31 cua3 brw-r--r-- 1 root root 2, 0 Sep 8 16:31 fd0 brw-r--r-- 1 root root 2, 12 Sep 8 16:31 fd0D360 brw-r--r-- 1 root root 2, 16 Sep 8 16:31 fd0D720 brw-r--r-- 1 root root 2, 28 Sep 8 16:31 fd0H1440 brw-r--r-- 1 root root 2, 12 Sep 8 16:31 fd0H360 brw-r--r-- 1 root root 2, 16 Sep 8 16:31 fd0H720 brw-r--r-- 1 root root 2, 16 Sep 8 16:31 fd0Q720 brw-r--r-- 1 root root 2, 4 Sep 8 16:31 fd0d360 brw-r--r-- 1 root root 2, 8 Sep 8 16:31 fd0h1200 brw-r--r-- 1 root root 2, 20 Sep 8 16:31 fd0h360 brw-r--r-- 1 root root 2, 24 Sep 8 16:31 fd0h720 brw-r--r-- 1 root root 2, 24 Sep 8 16:31 fd0q720 brw-r--r-- 1 root root 2, 1 Sep 8 16:31 fd1 brw-r--r-- 1 root root 2, 13 Sep 8 16:31 fd1D360 brw-r--r-- 1 root root 2, 17 Sep 8 16:31 fd1D720 brw-r--r-- 1 root root 2, 29 Sep 8 16:31 fd1H1440 brw------- 1 root root 2, 31 Sep 8 16:31 fd1H1722 brw-r--r-- 1 root root 2, 13 Sep 8 16:31 fd1H360 brw-r--r-- 1 root root 2, 17 Sep 8 16:31 fd1H720 brw-r--r-- 1 root root 2, 17 Sep 8 16:31 fd1Q720 brw-r--r-- 1 root root 2, 5 Sep 8 16:31 fd1d360 brw-r--r-- 1 root root 2, 9 Sep 8 16:31 fd1h1200 brw-r--r-- 1 root root 2, 21 Sep 8 16:31 fd1h360 brw-r--r-- 1 root root 2, 25 Sep 8 16:31 fd1h720 brw-r--r-- 1 root root 2, 25 Sep 8 16:31 fd1q720 brw-r----- 1 root root 3, 0 Sep 8 16:31 hda brw-r----- 1 root root 3, 1 Sep 8 16:31 hda1 brw-r----- 1 root root 3, 2 Sep 8 16:31 hda2 brw-r----- 1 root root 3, 3 Sep 8 16:31 hda3 brw-r----- 1 root root 3, 4 Sep 8 16:31 hda4 brw-r----- 1 root root 3, 5 Sep 8 16:31 hda5 brw-r----- 1 root root 3, 6 Sep 8 16:31 hda6 brw-r----- 1 root root 3, 7 Sep 8 16:31 hda7 brw-r----- 1 root root 3, 8 Sep 8 16:31 hda8 brw-r----- 1 root root 3, 64 Sep 8 16:31 hdb brw-r----- 1 root root 3, 65 Sep 8 16:31 hdb1 brw-r----- 1 root root 3, 66 Sep 8 16:31 hdb2 brw-r----- 1 root root 3, 67 Sep 8 16:31 hdb3 brw-r----- 1 root root 3, 68 Sep 8 16:31 hdb4 brw-r----- 1 root root 3, 69 Sep 8 16:31 hdb5 brw-r----- 1 root root 3, 70 Sep 8 16:31 hdb6 brw-r----- 1 root root 3, 71 Sep 8 16:31 hdb7 brw-r----- 1 root root 3, 72 Sep 8 16:31 hdb8 crw-r----- 1 root root 1, 2 Sep 8 16:31 kmem brw------- 1 root root 12, 0 Sep 8 16:31 loop0 brw------- 1 root root 12, 1 Sep 8 16:31 loop1 crw-r--r-- 1 root root 6, 0 Sep 8 16:31 lp0 crw-r--r-- 1 root root 6, 1 Sep 8 16:31 lp1 crw-r--r-- 1 root root 6, 2 Sep 8 16:31 lp2 brw-r--r-- 1 root root 12, 0 Sep 8 16:31 mcd0 crw-r----- 1 root root 1, 1 Sep 8 16:31 mem crw-r--r-- 1 root root 5, 65 Sep 8 16:31 modem crw-r--r-- 1 root root 5, 64 Sep 8 16:31 mouse crw-r--r-- 1 root root 27, 4 Sep 8 16:31 nrft0 crw-r--r-- 1 root root 27, 5 Sep 8 16:31 nrft1 crw-r--r-- 1 root root 27, 6 Sep 8 16:31 nrft2 crw-r--r-- 1 root root 27, 7 Sep 8 16:31 nrft3 crw------- 1 root root 9, 128 Sep 8 16:31 nrmt0 crw-r--r-- 1 root root 1, 3 Sep 8 16:31 null crw-r----- 1 root root 6, 0 Sep 8 16:31 par0 crw-r----- 1 root root 6, 1 Sep 8 16:31 par1 crw-r----- 1 root root 6, 2 Sep 8 16:31 par2 crw-r----- 1 root root 1, 4 Sep 8 16:31 port crw-r--r-- 1 root root 10, 1 Sep 8 16:31 ps2aux crw-r--r-- 1 root root 4, 128 Sep 8 16:31 ptyp0 crw-r--r-- 1 root root 4, 129 Sep 8 16:31 ptyp1 crw-r--r-- 1 root root 4, 130 Sep 8 16:31 ptyp2 crw-r--r-- 1 root root 4, 131 Sep 8 16:31 ptyp3 crw-r--r-- 1 root root 4, 132 Sep 8 16:31 ptyp4 crw-r--r-- 1 root root 4, 133 Sep 8 16:31 ptyp5 crw-r--r-- 1 root root 4, 134 Sep 8 16:31 ptyp6 crw-r--r-- 1 root root 4, 135 Sep 8 16:31 ptyp7 crw-r--r-- 1 root root 4, 136 Sep 8 16:31 ptyp8 crw-r--r-- 1 root root 4, 137 Sep 8 16:31 ptyp9 crw-r--r-- 1 root root 4, 138 Sep 8 16:31 ptypa crw-r--r-- 1 root root 4, 139 Sep 8 16:31 ptypb crw-r--r-- 1 root root 4, 140 Sep 8 16:31 ptypc crw-r--r-- 1 root root 4, 141 Sep 8 16:31 ptypd crw-r--r-- 1 root root 4, 142 Sep 8 16:31 ptype crw-r--r-- 1 root root 4, 143 Sep 8 16:31 ptypf brw-r----- 1 root root 1, 0 Sep 8 16:31 ram crw-r--r-- 1 root root 27, 0 Sep 8 16:31 rft0 crw-r--r-- 1 root root 27, 1 Sep 8 16:31 rft1 crw-r--r-- 1 root root 27, 2 Sep 8 16:31 rft2 crw-r--r-- 1 root root 27, 3 Sep 8 16:31 rft3 crw------- 1 root root 9, 0 Sep 8 16:31 rmt0 brw-r----- 1 root root 8, 0 Sep 8 16:31 sda brw-r----- 1 root root 8, 1 Sep 8 16:31 sda1 brw-r----- 1 root root 8, 2 Sep 8 16:31 sda2 brw-r----- 1 root root 8, 3 Sep 8 16:31 sda3 brw-r----- 1 root root 8, 4 Sep 8 16:31 sda4 brw-r----- 1 root root 8, 5 Sep 8 16:31 sda5 brw-r----- 1 root root 8, 6 Sep 8 16:31 sda6 brw-r----- 1 root root 8, 7 Sep 8 16:31 sda7 brw-r----- 1 root root 8, 8 Sep 8 16:31 sda8 brw-r----- 1 root root 8, 16 Sep 8 16:31 sdb brw-r----- 1 root root 8, 17 Sep 8 16:31 sdb1 brw-r----- 1 root root 8, 18 Sep 8 16:31 sdb2 brw-r----- 1 root root 8, 19 Sep 8 16:31 sdb3 brw-r----- 1 root root 8, 20 Sep 8 16:31 sdb4 brw-r----- 1 root root 8, 21 Sep 8 16:31 sdb5 brw-r----- 1 root root 8, 22 Sep 8 16:31 sdb6 brw-r----- 1 root root 8, 23 Sep 8 16:31 sdb7 brw-r----- 1 root root 8, 24 Sep 8 16:31 sdb8 brw------- 1 root root 8, 32 Sep 8 16:31 sdc brw------- 1 root root 8, 33 Sep 8 16:31 sdc1 brw------- 1 root root 8, 34 Sep 8 16:31 sdc2 brw------- 1 root root 8, 35 Sep 8 16:31 sdc3 brw------- 1 root root 8, 36 Sep 8 16:31 sdc4 brw------- 1 root root 8, 37 Sep 8 16:31 sdc5 brw------- 1 root root 8, 38 Sep 8 16:31 sdc6 brw------- 1 root root 8, 39 Sep 8 16:31 sdc7 brw------- 1 root root 8, 40 Sep 8 16:31 sdc8 brw------- 1 root root 8, 48 Sep 8 16:31 sdd brw------- 1 root root 8, 49 Sep 8 16:31 sdd1 brw------- 1 root root 8, 50 Sep 8 16:31 sdd2 brw------- 1 root root 8, 51 Sep 8 16:31 sdd3 brw------- 1 root root 8, 52 Sep 8 16:31 sdd4 brw------- 1 root root 8, 53 Sep 8 16:31 sdd5 brw------- 1 root root 8, 54 Sep 8 16:31 sdd6 brw------- 1 root root 8, 55 Sep 8 16:31 sdd7 brw------- 1 root root 8, 56 Sep 8 16:31 sdd8 brw------- 1 root root 8, 64 Sep 8 16:31 sde brw------- 1 root root 8, 65 Sep 8 16:31 sde1 brw------- 1 root root 8, 66 Sep 8 16:31 sde2 brw------- 1 root root 8, 67 Sep 8 16:31 sde3 brw------- 1 root root 8, 68 Sep 8 16:31 sde4 brw------- 1 root root 8, 69 Sep 8 16:31 sde5 brw------- 1 root root 8, 70 Sep 8 16:31 sde6 brw------- 1 root root 8, 71 Sep 8 16:31 sde7 brw------- 1 root root 8, 72 Sep 8 16:31 sde8 brw-r--r-- 1 root root 11, 0 Sep 8 16:31 sr0 brw-r----- 1 root root 11, 1 Sep 8 16:31 sr1 brw-r----- 1 root root 11, 2 Sep 8 16:31 sr2 brw-r----- 1 root root 3, 1 Sep 8 16:31 swap crw-r--r-- 1 root root 5, 0 Sep 8 16:31 tty crw-r--r-- 1 root root 4, 0 Sep 8 16:31 tty0 crw------- 1 root root 4, 1 Sep 8 16:31 tty1 crw-r--r-- 1 root root 4, 2 Sep 8 16:31 tty2 -rw-r--r-- 1 root root 20 Sep 8 16:31 tty21 crw-r--r-- 1 root root 4, 3 Sep 8 16:31 tty3 crw-r--r-- 1 root root 4, 4 Sep 8 16:31 tty4 crw-r--r-- 1 root root 4, 5 Sep 8 16:31 tty5 crw-r--r-- 1 root root 4, 6 Sep 8 16:31 tty6 crw------- 1 root root 4, 7 Sep 8 16:31 tty7 crw------- 1 root root 4, 8 Sep 8 16:31 tty8 crw-r--r-- 1 root root 4, 64 Sep 8 16:31 ttyS0 crw-r--r-- 1 root root 4, 65 Sep 8 16:31 ttyS1 crw-r--r-- 1 root root 4, 66 Sep 8 16:31 ttyS2 crw-r--r-- 1 root root 4, 192 Sep 8 16:31 ttyp0 crw-r--r-- 1 root root 4, 193 Sep 8 16:31 ttyp1 crw-r--r-- 1 root root 4, 194 Sep 8 16:31 ttyp2 crw-r--r-- 1 root root 4, 195 Sep 8 16:31 ttyp3 crw-r--r-- 1 root root 4, 196 Sep 8 16:31 ttyp4 crw-r--r-- 1 root root 4, 197 Sep 8 16:31 ttyp5 crw-r--r-- 1 root root 4, 198 Sep 8 16:31 ttyp6 crw-r--r-- 1 root root 4, 199 Sep 8 16:31 ttyp7 crw-r--r-- 1 root root 4, 200 Sep 8 16:31 ttyp8 crw-r--r-- 1 root root 4, 201 Sep 8 16:31 ttyp9 crw-r--r-- 1 root root 4, 202 Sep 8 16:31 ttypa crw-r--r-- 1 root root 4, 203 Sep 8 16:31 ttypb crw-r--r-- 1 root root 4, 204 Sep 8 16:31 ttypc crw-r--r-- 1 root root 4, 205 Sep 8 16:31 ttypd crw-r--r-- 1 root root 4, 206 Sep 8 16:31 ttype crw-r--r-- 1 root root 4, 207 Sep 8 16:31 ttypf -rw------- 1 root root 63488 Sep 8 16:31 ttys0 crw-r--r-- 1 root root 4, 67 Sep 8 16:31 ttys3 crw-r--r-- 1 root root 1, 5 Sep 8 16:31 zero boot_disk/etc: total 173 -rw-r--r-- 1 root root 53 Sep 8 18:48 boot.env -rwxr-xr-x 1 root root 27408 Sep 8 18:48 e2fsck* -rwxr-xr-x 1 root root 18540 Sep 8 18:48 fdisk* -rw-r--r-- 1 root root 69 Oct 8 12:27 fstab -r-x------ 1 root root 13312 Sep 8 18:48 getty* -rw-r--r-- 1 root root 334 Sep 8 18:48 group -rw-r--r-- 1 root root 12 Sep 8 18:48 host.conf -rw-r--r-- 1 root root 62 Sep 8 18:48 hosts -r-x------ 1 root root 6684 Sep 8 18:48 ifconfig* -rwxr-xr-x 1 root root 11492 Sep 8 18:48 init* -rw-r--r-- 1 root root 1017 Sep 9 22:12 inittab -rw-r--r-- 1 root root 0 Oct 8 12:19 issue -rw-r----- 1 root root 5137 Sep 8 18:48 login.defs -rwxr-xr-x 1 root root 14028 Sep 8 18:48 mke2fs* -rwxr-x--- 1 root root 2436 Sep 8 18:48 mkswap* -rwxr-xr-x 1 root root 11288 Sep 8 18:48 mount* -rw-r--r-- 1 root root 327 Sep 8 18:48 passwd -rwxr-xr-x 1 root root 383 Sep 10 16:02 profile* -rw-r--r-- 1 root root 94 Sep 8 18:48 protocols -rwxr-xr-x 1 root root 334 Oct 8 12:27 rc* -rwxr-xr-x 1 root root 9220 Sep 8 18:48 reboot* -r-x------ 1 root root 4092 Sep 8 18:48 route* -rw-r--r-- 1 root root 20 Sep 8 18:48 securetty -rw-r--r-- 1 root root 9749 Sep 8 18:48 services -rw-r--r-- 1 root root 36 Sep 8 18:48 shells -rwxr-xr-x 1 root root 13316 Sep 8 18:48 shutdown* -rwxr-xr-x 1 root root 2496 Sep 8 18:48 swapoff* -rwxr-xr-x 1 root root 2496 Sep 8 18:48 swapon* -rw-r--r-- 1 root root 5314 Sep 8 18:48 termcap -rwxr-xr-x 1 root root 5412 Sep 8 18:48 umount* -rw-r--r-- 1 root root 224 Sep 8 18:48 utmp -rw-r--r-- 1 root root 280 Sep 8 18:48 wtmp boot_disk/lib: total 629 -rwxr-xr-x 1 root root 17412 Sep 10 14:58 ld.so* -rwxr-xr-x 1 root root 623620 Sep 8 18:33 libc.so.4* <sect2>Utility Disk ls-lR Directory Listing <p> The utility listing is of directory util_disk: total 1 drwxr-xr-x 2 root root 1024 Sep 10 16:05 bin/ util_disk/bin: total 897 -rwxr-xr-x 1 root root 41984 Sep 10 14:11 cpio* -rwxr-xr-x 1 root root 504451 Sep 9 21:39 ftape.o* -rwxr-xr-x 1 root root 63874 Sep 9 21:40 gzip* -rwxr-xr-x 1 root root 13316 Sep 9 21:34 insmod* -rwxr-xr-x 1 root root 58 Sep 9 21:34 lsmod* -rwxr-xr-x 1 root root 3288 Sep 9 21:34 mknod* -rwxr-xr-x 1 root root 9220 Sep 9 21:34 rmmod* -rwxr-xr-x 1 root root 226308 Sep 9 22:13 tar* 4.2. Shell Scripts to Build 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. Then 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 1994. 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/vmlinux $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 1994. 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 vmlinuz 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 vmlinuz /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 Minor device number - see below 0X01FD 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=<device> of=<filename> where <device> = 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=<device> 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: vmlinux 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. 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 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 6.4. 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 6.5. 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.