Boot Disks
A very important, but separate, part of your backup strategy should be the creation and maintenance of boot disks. These disks are used in the event of an emergency with your system (they are in fact sometimes called emergency boot disks). They are designed to enable you to quickly and easily correct large-scale software and operating system problems with your PC, and to allow you to reconfigure or update your system without being totally dependent on the contents of your hard disk.
This section discusses boot disks and how they work, and provides details on how to make and use them effectively.
Importance of Boot Disks:
You rely on your hard disk to boot your PC each day, but what would happen if something happened to your hard disk to make it unbootable? There are many different situations that can cause this to happen, ranging from hardware failure to erroneous operating system upgrades to virus infections. In addition to a backup of your data and programs, you need a backup of your bootable operating system so you can start the PC even when something happens to your hard disk. This is what emergency boot disks are for.
Typically, a boot disk will be used in the following situations:
Booting the System
In the event that your hard disk fails and is unable to boot, you can use your boot disks to start up the system. This will allow you the opportunity to troubleshoot and hopefully correct the problem with the hard disk. Sometimes a hard disk will be accessible after booting from a floppy disk, even if the hard disk itself will not boot. Without a boot disk, you are dead in the water since you will be unable to even start up the system at all.
Disaster Recovery
Ideally, the restore software for your backup media should be on an emergency boot disk. This will enable you to recover from a hard disk disaster and restore your system from your last backup media set(s).
Virus Detection and Disinfection: Many viruses, especially boot sector infectors, will automatically load into memory every time the hard disk is used to boot the PC. Once in memory they will interfere with attempts to remove them from the system. To avoid this, a virus disinfection session should always be done after a boot from a floppy disk that is known to be clean and functional.
Hard Disk Upgrade or Installation
A new hard disk normally comes unformatted with no operating system on it, and therefore cannot be used to boot the system. The normal way to get the operating system onto the disk is to use a boot floppy to start up the system and then transfer the operating system files to the hard disk.
Boot Disk Contents
Depending on how you use your system, you may have one or several boot disks. The main reason for this is that programs are getting larger and larger, and it can be difficult to get all of the contents that you need onto one disk. In addition, many programs such as the Norton Utilities or backup software with disaster recovery, will volunteer to create their own boot disks, sometimes called "emergency disks" or "rescue disks". These will normally use separate physical disks, and sometimes duplicate some of the information that is on your "homemade" disks. There is nothing wrong with this at all, as long as you don't end up with a ridiculous quantity of boot disks.
Regardless of how many disks you have, you should always have duplicates of every one in the set. The simple fact is that floppy disks have a high rate of failure, and you do not want to get a "Sector not found reading drive A:" error as you attempt to reboot to recover from some disaster.
If you have multiple boot disks, it isn't really necessary for every one of them to be bootable. ("Huh?") What I mean is that if you only have one boot disk that holds all the files you need, you must ensure that it contains the operating system files that will let you boot the system. If your boot disk set includes several disks holding items such as your antivirus software or other files, they don't all need to be bootable as long as you have at least two disks that will let you boot the system.
Remember that especially with the operating system and system utilities files, you need to put on the disk the programs that are appropriate to whatever operating system you are using. Putting a copy of DOS 6.22's FORMAT.COM on a Windows 95 boot disk is pointless, because it will not run if the system is booted by that disk (which is DOS 7.x).
Here are some of the items that I think it is important for you to consider putting on your set of boot disks:
Operating System
The boot disk (at least some of them) must be capable of booting the computer, of course. This means creating a boot disk that contains whatever files your operating system needs to boot up; see this section for more on creating the boot disk itself.
System Configuration Files
Assuming you are using DOS or a DOS-based operating system like Windows, it's a good idea to include your CONFIG.SYS and AUTOEXEC.BAT files on the boot disk. You may want to rename them however, so that they aren't automatically used by the floppy disk when it boots (since these files will contain lines referring to items on your hard disk that may not work when booting from a floppy).
Hard Disk Partitioning and Format Utilities
You definitely need utilities on the boot disk that will allow you to partition and format your hard disk if you need to. This means, at a very minimum, including the programs FDISK.EXE, FORMAT.COM and SYS.COM on the disk. Make sure you use the versions corresponding to the operating system you put on the disk, or the programs will give an "Incorrect DOS version" error and will not run. If you have a copy of Partition Magic or a similar partitioning utility, creating a floppy disk with this utility on it can be very useful; follow the directions that come with the software to create one.
CD-ROM Driver and MSCDEX
In order to allow the installation of CD-ROM-based operating systems, you must be able to access your CD-ROM drive. This requires two pieces of software: a CD-ROM driver and the file system extension MSCDEX.EXE that comes with the operating system you are using. Make sure both are included and that the driver is loaded in the CONFIG.SYS system file and MSCDEX.EXE in the AUTOEXEC.BAT system file.
Diagnostic Utilities
If you have diagnostic utility software on your PC, including a copy on a disk can be very useful for troubleshooting problems with your system. At a very minimum, include SCANDISK.EXE so you can scan for file system problems if need be, and MSD.EXE (Microsoft Diagnostics) so you can check your system setup, installed disks, ports and channels.
Restore Software
If you are using backup software that comes with disaster recovery capabilities, the application should create or allow you to create a floppy disk that contains the program that will restore your system from backup. Make sure that you create this disk and include it as part of your boot disk set.
Image Information
Image information created from your hard disk file system should be stored on a floppy disk to allow you to recover from disk problems.
Antivirus Software: Good antivirus products will include a floppy-disk-based version of their software, which will allow you to boot and run the antivirus scanner directly from the floppy disk. This is very useful since it will allow you to bypass any viruses on the hard disk. It isn't always possible to do this with all antivirus software, however, so you may have to boot from a clean floppy disk and then run the scanner from the hard disk (which should still work in most cases but isn't nearly as good.)
Editor
Many people don't think of this, but including a simple editor on the disk like DOS's EDIT.COM will allow you to make quick changes to configuration files if you need them, which can be a real life-saver.
Miscellaneous File Utilities: Any other file utilities you may have that you find useful should definitely be considered. For example, a simple file-transfer program can be helpful in setting up a new PC. I sometimes like to have DEFRAG.EXE on a boot disk, and MEM.EXE is helpful in diagnosing memory usage on a new or just-upgraded system. PKUNZIP.EXE comes in handy for dealing with ZIP files, of course. And DOSKEY.COM is a helpful addition as well to any boot disk, as it will save you a lot of typing by letting you recall and reuse previously-typed commands.
If you are using something like Norton Utilities or similar, a good antivirus product, and a backup program with disaster recovery, you may find that you will end up with several different emergency boot disks or "rescue disks". Again, there is nothing wrong with this at all, since floppies are pretty cheap. The only possible disadvantage is that you will spend more time keeping them all up to date.