4.2 Disk Operating System (DOS)
4.2.4 Creating a DOS boot disk
There are times when things do not go as expected, and the computer has trouble starting. To troubleshoot the problem, an alternate way of starting the system is needed. A DOS boot disk is a great tool to use to perform this task. One of its most useful functions is in booting a newly assembled computer to install the operating system. A DOS boot disk is just a floppy disk with three necessary system files on it:
  • COMMAND.COM
  • IO.SYS
  • MSDOS.SYS

It is a good idea to place diagnostic programs on this disk as well. To create the boot disk perform the following steps (this process assumes DOS is installed on the hard disk):

  1. Start the computer.
  2. Insert a blank floppy disk in the drive.
  3. At the command prompt type FORMAT A: /s and press Enter.
  4. If the disk is already formatted, type SYS A: and press Enter.
     
Lab Activity  (PDF, 10 KB)
  In this lab, students will know which files are necessary to make a floppy disk bootable. Also, students will know the commands necessary to create a boot disk.