XT bus architecture
<hardware, architecture> (After the
IBM PC XT) An eight-bit
ISA bus architecture used by
Intel 8086 and
Intel 8088 systems in the
IBM PC and
IBM PC XT in the 1980s.
It predates the 16-bit ISA architecture used on the
Intel 80286 based machines.
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 disc controller
