Notes on MS-FORMAT.COM

Versions of FORMAT.COM used in the Boot Record Studies at The Starman's Realm :

   OS Type      Filename   File Size   Release  Date
 -----------   ----------  ---------  ---------------
 MS-DOS 5.0    FORMAT.COM   32,911    04-09-91  5:00a
 MS-DOS 5.0    FORMAT.COM   33,087    11-11-91  5:00a
 MS-DOS 6.0    FORMAT.COM   22,717    03-10-93  6:00a
(Boot Record same as MS-DOS 5.0)
 MS-DOS 6.2    FORMAT.COM    n,nnn    09-30-93  6:20a
 MS-DOS 6.22   FORMAT.COM   22,974    05-31-94  6:22a
 Windows 95(A)
(MS-DOS 7.0)   FORMAT.COM   nn,nnn    07-11-95  9:50a
 Windows 95B
(MS-DOS 7.1)   FORMAT.COM   nn,nnn    08-24-96 11:11a
 Windows 98
(MS-DOS 7.1)   FORMAT.COM   nn,nnn    05-11-98  8:01p


 Windows 98 SE
(MS-DOS 7.1)   FORMAT.COM   nn,nnn    04-23-99 10:22p
 Windows ME
(MS-DOS 8.0)   FORMAT.COM   nn,nnn    06-08-00  5:00p

All Versions of FORMAT.COM

The MS-DOS 5.0 versions of FORMAT.COM used EXE2COM to pack some apparently sensitive parts of the file; whereas later versions (such as MS-DOS 6.0) were compressed with PKlite (1.15) in order to save space on the floppy disks as well. However, since the release of Windows 95, Microsoft has stopped packing its FORMAT.COM files.

Beginning with Windows 95, every FORMAT.COM file clearly contains TWO different and complete copies of that particular OS version's Boot Record: The first is used for both FAT12 and FAT16 file systems on either floppy or hard disks. The second is for the FAT32 file system on hard disks only. The Floppy Disk Boot Record has, of course, always been 512 bytes in length, but beginning with Windows 95B (and the introduction of Microsoft's 32-bit FAT file system) the size of the Hard Disk Boot Record increased to 1,536 bytes (or three whole sectors); most of the second sector is nothing but zeros though.

Note: Windows ME is a special case! The FORMAT.COM program for WinME does not function the same as the others (read the section on Windows ME below). For all other versions, entering FORMAT /? at a DOS prompt displays:

Copies MS-DOS system files and command interpreter to a disk you specify.

FORMAT [drive1:][path] drive2:

  [drive1:][path] Specifies the location of the system files.
  drive2:         Specifies the drive the files are to be copied to.

MS-DOS 6.2 and 6.22

Both of these FORMAT programs are packed with PKLITE 1.15 and expand to a size of 13,824 bytes. Each contains the phrase "DOS Version 6 (C)Copyright 1981- " with version 6.2 ending in 1993 and version 6.22 ending in 1994.

Windows 95(A)

Windows 95's FORMAT.COM contains the DOS Copyright phrase: "MS-DOS Version 7 (C)Copyright 1981-1995"

Windows 95B, 98 and 98 SE

All three of these Windows OS versions contain the same exact DOS Copyright phrase as the one found in the original Windows 95 FORMAT.COM.

Windows ME (Millennium Edition)

Windows ME contains the phrase "MS-DOS Version 8 (C)Copyright 1981-1999" and functions much different than previous versions of this program. If you enter FORMAT /? at a DOS prompt, it responds with:

Restores Windows boot file, IO.SYS, to drive C:.

FORMAT C:

  C:     Specifies the drive the files are to be copied to. Must be C:

And attempting to FORMAT a floppy disk using " sys a: " causees Win ME's FORMAT program to respond with:

   You can only FORMAT drive C: to try and repair the boot hard disk.
   Use the Startup Disk option in Add/Remove programs to create
   an emergency boot disk.

In light of this restriction, it might seem weird that a FAT12/FAT16 Boot Record is still inside its FORMAT program. One wouldn't normally be using a hard drive with Win ME that's small enough (under 512 binary MB) to require its use, but it's still here if you do. There are also some who wish to still continue using FAT16 on their hard drives rather than switching to FAT32, but they are limited to a capacity of only 2047 binary MB (or about 2 GB) per partition and must use a very wasteful cluster size of 32 KB in order to do so! When I used FAT16, I had always tried to keep my partitions under 256 binary MB so I could use a cluster size of only 4 KB (which is what you'll normally get using FAT32).

For those who were running a dual booting system with FAT32 and NTFS or FAT32 and Linux file systems on the same drive, it used to make sense to have a small FAT16 partition near the beginning of a large hard disk in order to swap files between these OSs. However, with the release of Windows 2000 (also known as Win2k or NT5) which can use FAT32 as well as NTFS file systems and the many Linux distributions that can understand even more file systems, the need for a FAT16 partition is far less likely these days.

Last Update: 29 December 2002.

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