The XT bus has four DMA channels, of which three are brought out to the expansion slots. Of these three, two are normally allocated to machine functions:
DMA channel | Expansion | Standard function |
---|---|---|
0 | No | {dynamic RAM} refresh |
1 | Yes | add-on cards |
2 | Yes | {floppy disk} controller |
3 | Yes | {hard disk} controller |
See also
Article based on XT bus architecture at FOLDOC, used with permission.