[ The PC Guide | Systems and Components Reference Guide | Motherboard and System Devices | System Resources | Direct Memory Access (DMA) Channels | DMA Channel Function and Operation ]
Summary of DMA Channels and Their Typical Uses
The table below provides summary information about the 8 DMA channel numbers in a typical PC. You may find this table useful when considering how to configure your system, or for resolving DMA conflicts. For an explanation of the categories, along with more detailed descriptions, see here. To see DMA channel usage organized by device instead of DMA number, see this device resource summary.
DMA |
Bus Line? |
Typical Default Use |
Other Common Uses |
0 |
no |
Memory Refresh |
None |
1 |
8/16-bit |
Sound card (low DMA) |
SCSI host adapters, ECP parallel ports, tape accelerator cards, network cards, voice modems |
2 |
8/16-bit |
Floppy disk controller |
Tape accelerator cards |
3 |
8/16-bit |
None |
ECP parallel ports, SCSI host adapters, tape accelerator cards, sound card (low DMA), network cards, voice modems, hard disk controller on old PC/XT |
4 |
no |
None; cascade for DMAs 0-3 |
None |
5 |
16-bit only |
Sound card (high DMA) |
SCSI host adapters, network cards |
6 |
16-bit only |
None |
Sound cards (high DMA), network cards |
7 |
16-bit only |
None |
Sound cards (high DMA), network cards |
Next: DMA Channel
Details By Number
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