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On Sat, 26 Jan 2002 10:04:05 -0700, don clay wrote: >This message is from the T13 list server. >3. The device will pause data transfer only between sectors by waiting to post >the interrupt and raise DRQ in PIO mode or by de-activating DMAREQ in any >DMA mode. Ahhh... Not true... There is no requirement (never has been a requirement) that the device pause or terminate a burst at a sector boundary. There may be some drives that did that but I don't think it was or is a common pratice. In MW DMA is was common for host and/or devices to terminate the burst every 64, 128, 256 words (pick one) so that some stupid ISA bus motherboards had time to do DRAM memory refresh cycles. Today I would expect to see Ultra DMA pauses any time the host or device FIFO full/empty conditions require it and that has nothing to do with sector boundaries. I would not expect Ultra DMA burst termination at every sector boundary or even expect that when burst terminations happen they happen at a sector boundary. We must be very careful here... No one should design a host or device that expects DMA bursts to pause or terminate at sector/block boundaries. I think this has been one of the things confusing Pat (Pat is that true?). *** Hale Landis *** www.ata-atapi.com *** Subscribe/Unsubscribe instructions can be found at www.t13.org.
