The disk is said to be a BOOTABLE if it contains the following 3 files-

IO.SYS , MSDOS.SYS , COMMAND.COM .

If these files are not present then it gives error message "Invalid system disk Replace the disk, and then Press any key " . When these files are found "starting MS-DOS..." message appears on the screen & finally the prompt is seen.This is called as a booting .

---

HOW TO CREATE DISK (BOOTABLE)

Format/s [drive] :- (CAUTION) This command formats a disk.

Sys [ Source drive ] [Target drive] :- File named sys.com must be present in the source drive and source drive should be bootable.

A proper bootable floppy should have following files in addition to system files.

format.com
fdisk.exe
attrib.exe
sys.com
mscdex.exe

NOTE

1. Sometimes computer is required to be booted from floppy drive then CHANGE BOOT SEQUENCE from setup by using pageup or pagedown key.
2. Every computer user should have a bootable write protected FLOPPY DISKETTE.

This site forever be under construction.