Backing up to Floppy Disks in MS-DOS 4.0 and 5.0 (38112)

The information in this article applies to:
    Microsoft MS-DOS operating system 4.0
    Microsoft MS-DOS operating system 5.0

This article was previously published under Q38112


When using a floppy-disk drive as the destination drive, MS-DOS versions 4.x and 5.x BACKUP.COM automatically format the destination disk if necessary. To format the disk, BACKUP executes FORMAT.COM.

To find FORMAT.COM, BACKUP first searches the current directory, and then uses the PATH environment variable for search paths if FORMAT.COM is not found in the current directory. When BACKUP finds FORMAT.COM, it checks to see if FORMAT.COM is on the destination disk. If FORMAT.COM is on the BACKUP destination disk, BACKUP continues the search. If FORMAT.COM is not found, or if it is found only on the destination disk, BACKUP gives the following message and terminates:

FORMAT.COM not found


The following are workarounds for this problem:
    If more than one drive is available, make sure that either the second drive contains FORMAT.COM and is in the PATH, or the second drive is the destination drive.
    If the system has only one disk drive, the following statement will cause the destination drive to be the same physical drive, but a different logical drive:

    backup a:\<file specification> b: <possible switches>

    If the destination disk has a different capacity than the destination disk drive (for example, a 360K disk in a 1.2-megabyte disk drive), you need to specify this using the /f: switch with the BACKUP command. For example, suppose drive B is a 1.2-megabyte drive, and the destination disk is a 360K disk. To back up all the files on drive A to drive B, the following command is needed:

    backup a:\*.* b: /f:360k

Modification Type: Major Last Reviewed: 10/13/2003
Keywords: KB38112