A Reference Guide for the Boot Record pages:
The MSDOS5.0 (5.0 through
6.22) Boot Record created by FORMAT.COM
The MSWIN4.0 (Windows 95A) Boot
Record created by FORMAT.COM
The MSWIN4.1 (Windows 95B/98/98SE/ME)
Boot Record created by FORMAT.COM
Confused? Send
me an email if you have a specific question about the MBR or other Boot
Records...
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"
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 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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