“Floppy boot protection” prevents a computer from being started from a diskette, with subsequent access to the hard disk. It is one of the fundamental elements in a security system. If drive C: can be accessed after booting from a diskette, this represents a gaping hole in your security. One common misconception is that the BIOS can provide security. Most modern computers allow the user to configure the BIOS so that the computer cannot be started from drive A:. This feature only lasts as long as the computer's internal battery. If the power supply to the BIOS chip is interrupted, all your settings are lost, and the BIOS will use its default values the next time it starts. Furthermore, it remains possible simply to move the hard disk to another computer whose BIOS settings do allow drive A: booting. The master boot sector is made up of a program and data. FDISK stores a standard program, while the data varies according to how the hard disk is partitioned. Some users allocate all disk space to drive C:, while others subdivide the space into drives C: and D:. A program offering ‘Floppy boot protection’ must replace the Master Boot Program with its own program, and encrypt the partition data. This prevents access to the hard disk after an attempt is made to start the computer from a boot diskette. When a boot diskette is used, only the following message is displayed: Invalid drive C: A large number of programs read partition data directly from the Master Boot Sector. The programs must be able to continue doing this even with ‘Floppy boot protection’ installed. Most access control programs are able to handle this situation. A good floppy boot protection system should also provide a security function that prevents the hard disk from being moved to another computer.