Microsoft KB Archive/34908

= Determining Physical Drive Numbers =

Article ID: 34908

Article Last Modified on 11/16/2006

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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 Q34908



SUMMARY
There is some confusion about determining the physical drive number of a floppy drive for use with DRIVPARM or DRIVER.SYS. The first drive is floppy drive A, referred to as physical drive 0. Floppy drive B is referred to as physical drive 1. On systems that do not have a physical drive B, MS-DOS creates a logical entry for it (in the drive parameter table) that maps back to floppy drive A. This allows systems with only one floppy drive to copy files from one floppy disk to another by referring to the one drive as both drive A and drive B.

On systems with an XT-class ROM BIOS, there are two additional floppy drives, physically numbered 2 and 3, that can be available. On IBM PC AT and PS/2-class ROM BIOS systems, there are only two floppy drives available.

Additional query words: 6.22 3.x 4.00 5.00 5.00a 6.00 6.20 6.21

Keywords: KB34908

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