4 Feb
2007
4 Feb
'07
2:40 p.m.
Tony Duell wrote:
I thought every PC (maaning IBM compatible) did that.
The floppy system
in the PC. XT and ZT has a DMA channel associated with it. You ask it to
read some secotyors from the current track, it does so and transfers the
data into memory, then gives you an iterrupt when it's done.
Well on some
computers, like the COCO the IRQ only is used
to end the cpu polling loop for the floppy.Since the default
OS is CP/M err MSDOS I expect the hardware is not used effectivly.
I know for a fact that other tasks carry on running on this (slow) linux
machine when it's doing floppy drive operations.
-tony