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> PIO works better than MW/SW-DMA, > Most ATAPI devices ... even many ... MW/SW-DMA Agreed, thank you for your cogent corrections. So then our question now is what will the initial Atapi UDma ramp feel like? Given that Win95B Atapi Pio choked over odd byte counts, has enough app software learned to duck them that they won't be an issue for Atapi UDma? Or will we revisit the pain we felt then, teaching people to continue to turn off Dma? And will the license Atapi UDma gives the receiver to discard quietly the last few bytes covered by the last Crc often matter? Will any of this become more clear over time? I can easily imagine Apple is never so rude as to pass on to its customers the mystery over when to turn off Dma ... I wonder if down inside Apple ever turns it off, never turns it off, what? Pat LaVarre >>> Eschmann, Michael K 04/11/02 22:46 PM >>> This message is from the T13 list server. I'll add that PIO works better than MW/SW-DMA, since many folks have screwed up those versions of DMA quite imaginitively. UDMA seems to be quite healthy on the vast majority of devices I've seen. Most ATAPI devices of more than a year old (and even many now still) are MW/SW-DMA, which is why many folks still use this Windows checkbox. -----Original Message----- From: Pat LaVarre [mailto:[EMAIL PROTECTED]] Sent: Wednesday, April 10, 2002 4:38 PM To: [EMAIL PROTECTED] Subject: RE: RE: [t13] UDMA Bursts - Pause versus Termination This message is from the T13 list server. Pio works better than Dma. We know this because we know people use the checkbox that Microsoft provides to turn Dma off. x4402 Pat LaVarre [EMAIL PROTECTED] http://members.aol.com/plscsi/ >>> Ooi, Thien Ern 04/10/02 04:59PM >>> This message isfrom the T13 list server. I don't understand. How is that different from MW-DMA and UDMA? T.E. -----Original Message----- From: Hale Landis [mailto:[EMAIL PROTECTED]] Sent: Wednesday, April 10, 2002 2:22 PM To: [EMAIL PROTECTED] Subject: RE: RE: [t13] UDMA Bursts - Pause versus Termination ... Another question: Can you give me one good reason why (5 years ago!) the host side should not be able to use a PRD list for PIO data transfers and have the host adapter preform the equivalent of the x86 REP INSx/OUTSx instructions? Given the popularity of ATA/ATAPI and all the improvements done in device designs there is no excuse for the host adapter side of the interface to be in such a sad state! ... *** Hale Landis *** www.ata-atapi.com ***
