My teacher in school is teaching that DMA is no longer in use because it
is too slow...
Then how come that hard disk is faster in DMA than in PIO mode?
Did that teacher specify that PIO was the faster alternative (which of
course is untrue)?
It might've been simply that "DMA" was being considered in a vague
sort of way, as single or multi-word, not ultra DMA.
Always take what a lower-level course instructors say with a grain of
salt... an unfortunate side-effect of Windows is that it makes *some*
people feel more competent than they really are... even in areas not
so directly related to windows.
Here's a site to get a little more basic info:
http://www.storagereview.com/guide2000/ref/hdd/if/ide/modesDMA.html