Microsoft KB Archive/70746

Problems with MS-DOS 3.20 Format Command PSS ID Number: Q70746 Article last modified on 02-08-1993 PSS database name: O_MSDOS

3.20

MS-DOS

The information in this article applies to:

- Microsoft MS-DOS operating system version 3.20

Problem:

I am unable to format 1.2 MB disks in my high-density drive using DOS version 3.20. Is this a problem with MS-DOS or my disk drive?

Response:

There are problems with the FORMAT.EXE supplied with MS-DOS 3.20. Most notable is the inability to format 1.2 MB disks in a high-density drive. Attempts to format result in the error message:

“Invalid media or track 0 Bad - disk unusable” Format failure Format another?(Y/N)

Neither DRIVPARM or DRIVER.SYS allow formatting to occur. Specifying tracks and sectors by /t:80 /n:15 gives an “invalid switch” error.

Format also returns an “invalid switch” error when you attempt to format a 360K disk in a 1.2 MB drive using the switches /t:40 /n:9. 360K disks must be formatted in a high-density drive using the /4 switch.

The only way to format 1.2 MB diskettes is to upgrade the version of MS-DOS on the computer. An upgrade to MS-DOS 3.21 will probably not require a reformat because the 3.21 system files should fit onto the sectors alloted to 3.20 system files.

WARNING: It is imperative that you back up the hard drive before you try to install DOS 3.21 over DOS 3.20. While in most cases no problems will be encountered, it is possible that the sectoring scheme used by MS-DOS 3.21 will be incompatible with the scheme used by the DOS 3.20 currently installed on the computer. In these cases, an upgrade will result in loss of data on the hard drive.

MS-DOS 3.20 can read from and write to 1.2 MB floppy disks that have been previously formatted using another version of MS-DOS. Thus, if you want to purchase preformatted disks or to format the disks on another machine, you can use 1.2 MB floppy disks.

Additional reference words: 3.20 noupd

Copyright Microsoft Corporation 1993.