What files are needed to boot a computer?

MS-DOSThe computer needs the minimum of the below three files to boot to an MS-DOS prompt.

command.com
io.sys
msdos.sys

Note: The above files are the absolute minimum. If an external command such as fdisk needs to be performed, that file also needs to be copied to the disk or drive. See the boot disk page for additional information and recommendations on what files to copy or how to create a bootable diskette.

Note: Other operating systems may use different files to boot into their operating system. These files are only for computers booting into MS-DOS.