re ide vs scsi in article apr julian uwo ca wlsmith valve heart rri uwo ca wayne smith writes in article wayne uv amtower spacecoast org wayne amtower spacecoast orgx newssoftware grn f by mike schwartz michael b smith writes but i still want to know why it intrinsically better than ide on an isa bus when it comes to multi tasking os s when managing data from a single scsi hard drive a scsi controller that transfers data by dma allows the cpu to request data from the hard drive and continue working while the controller gets the data and moves it to memory ide also uses dma techniques i believe floppy controller also uses dma and most a d boards also use dma dma is no big deal and has nothing to do directly with scsi ide does not do dma this is because it s like te pc at hard disk interface the controller moves a sector to some buffer memory on the controller card then the cpu moves the data from the buffer to main memory where it s needed if ide doesn t work this way then it s not compatible heck if ide used dma then you d hear all kinds of complaints about isa bus systems with more than m ram not working with their ide drives m is the dma addressing limit of the isa bus and if ide did dma there would be trouble btw there are dma enabling signals in the ide cable spec but the last report i heard was that they are never implemented because it would require a different kind of ide adapter and different drivers richard krehbiel richk grebyn com os will do for me until amigados for the comes along
