Microsoft KB Archive/60082

= Using IBM PC-DOS 4.0 with MS-DOS Hard Disk Partition =

Article ID: 60082

Article Last Modified on 5/12/2003

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APPLIES TO


 * Microsoft MS-DOS 3.1
 * Microsoft MS-DOS 3.2 Standard Edition
 * Microsoft MS-DOS 3.21 Standard Edition
 * Microsoft MS-DOS 3.3 Standard Edition
 * Microsoft MS-DOS 3.3a
 * Microsoft MS-DOS 4.0 Standard Edition
 * Microsoft MS-DOS 4.01 Standard Edition
 * Microsoft MS-DOS 5.0 Standard Edition
 * Microsoft MS-DOS 5.0a
 * Microsoft MS-DOS 6.0 Standard Edition
 * Microsoft MS-DOS 6.2 Standard Edition
 * Microsoft MS-DOS 6.21 Standard Edition
 * Microsoft MS-DOS 6.22 Standard Edition

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This article was previously published under Q60082



SUMMARY
IBM PC-DOS versions 4.0, 4.01, and 5.0 do not recognize hard disk partitions other than those created with IBM products. If the boot sector's original equipment manufacturer (OEM) name field does not have &quot;IBM &quot; as the first four characters, an &quot;invalid media&quot; error is returned, and you are not allowed access to the hard disk.



MORE INFORMATION
For MS-DOS (and all other non-IBM DOS) partitions, this problem can be corrected by backing up the partition and then reformatting the partition with IBM PC-DOS. After reformatting, the information backed up can be restored to the partition. Because MS-DOS does not distinguish the OEM stamp in the boot sector, the new partition (less than 32 MB) is recognized by all versions of MS-DOS that recognize a 16-bit file allocation table (FAT).

If reformatting the hard disk drive is not a feasible alternative, you can also manually change the boot sector so that IBM PC-DOS versions 4.x and later can recognize it. To alter the boot sector manually, enter the following:

 Type debug and press ENTER.  Enter the following commands:    -L 0 n 0 1     ; Loads the boot sector of the drive into ; address 0, where n is the drive (0=A, etc.). -D 0          ; Displays the boot sector. -E 03         ; Edit starting with the fourth byte. 

The fourth byte of the boot sector is displayed in hexadecimal, followed by a colon. To change the bytes, type the hexadecimal value of the replacement character at the prompt.

The prompt appears as &quot;XX:_&quot;, where XX is the current value. To enter more than one value, press the SPACEBAR after entering the value. To correct the OEM stamp, enter the following at the prompt: 49424D20 ; Puts &quot;IBM &quot; in OEM stamp

-D 0         ; Displays boot sector with changes. -W 0 n 0 1   ; Writes the boot sector to the drive from ; address 0, where n is the drive (0=A, etc.). -Q           ; Exits Debug; the sector is now correct.

Additional query words: 6.22 3.20 3.21 3.30 3.30a 4.00 4.01 5.00 6.00 6.20

Keywords: KB60082

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