Microsoft KB Archive/104418

= Direct Memory Access (DMA) Channels and Descriptions =

Article ID: 104418

Article Last Modified on 5/6/2003

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APPLIES TO


 * Microsoft MS-DOS 2.11 Standard Edition
 * 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 Q104418



SUMMARY
A direct memory access (DMA) channel provides high speed data transfer between a peripheral device, such as a disk drive controller, and memory without intervention by the CPU. Listed below are the DMA channels for the IBM PC and XT class machines and the IBM AT and above class machines.   IBM PC and XT   -

DMA Channel       Description ---

0              Dynamic RAM Refresh 1              Reserved 2              Floppy Disk Controller 3              Hard Disk Controller

IBM AT and Above

DMA Channel       Description ---

0              Reserved 1              SDLC Controller 2              Floppy Disk Controller 3              Hard Disk Controller 4              Cascade from DMA channels 0 - 3 5              Reserved 6              Reserved 7              Reserved

