CompuServe Messages

Wayne: it might not be a 'macht nichts' situation. Then again, ? True DMA is almost always preferable, as it (like the blitter) takes another load off the cpu. Of course, someone would need to add an identical drive to a 2000 and do some tests to see just how much difference there is. It might not be a lot when going to chip ram. The 32-bit access to the chip RAM in the 3000 should help, tho. Its DMA chip will gather up 32-bits from the SCSI port at a time, and then write it all at once to the chip ram. That should mean less contention with the cpu/blitter (which it must have priority over) than otherwise. Unless… Hmmm. If the DMA to video ram is _only_ during blanking (like floppy DMA), then non-DMA could be far faster! Double hmmm. Hires video mode is a stickler too. Unless they pulled some kind of trick in order to transfer 16-bits first to one video bank, then the other, DMA wouldn't help much at all no matter what. Drat. This is one reason I don't like it when articles and press releases don't go into details (and tech manuals are unavailable)… makes me nervous debating speed relationships ;-). Everything depends on just how fancy CBM implemented things.