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> > I'd love to hear people evaluate this claim. Does anyone on > > Earth know of Atapi devices that don't put a zero there? ... > Don't know... Good question. One other thought: last I checked (1999?) Microsoft WHQL required SFF, not Ansi. > > Offline I've seen the claim that nearly all actual Atapi > > devices, if intepreted per Ansi, > > TELL the host to use SFF rather than Ansi. Specifically, this > You mean interpreted per T10 MMC-x, correct? Yes Ansi T10 http://www.t10.org/scsi-3.htm ftp://ftp.t10.org/t10/drafts/s2/s2-r10l.pdf Or ftp://ftp.t10.org/t10/drafts/spc2/spc2r20.pdf Or .... On this issue of what a zero means at offset 2 of the data copied by op x12 Inquiry, AFAIK, all the T10 publications agree. > T13 doesn't describe the SCSI command set for any ATAPI device. This reality doesn't make a T13 claim that T13 specifies how the host and the device come to agreement over how many bytes to copy which way too very credible, does it? > T13 only defines the ATA/ATAPI physical > transport and PACKET command protocol. Except T13 left out from AtapiDma the feature of letting the device ask to copy arbitrary counts of bytes that AtapiPio offered. x4402 Pat LaVarre [EMAIL PROTECTED] http://members.aol.com/plscsi/ >>> Hale Landis 04/12/02 10:52AM >>> This message is from the T13 list server. On Fri, 12 Apr 2002 07:46:25 -0600, Pat LaVarre wrote: >This message is from the T13 list server. >Offline I've seen the claim that nearly all actual Atapi >devices, if intepreted per Ansi, You mean interpreted per T10 MMC-x, correct? Because T13 doesn't describe the SCSI command set for any ATAPI device. >TELL the host to use SFF rather than Ansi. Specifically, this >claim says that ... In response to the standard, start of life, >plug 'n play query of `plscsi -v -x 12 0 0 0 24 0 -i x24`, most >actual Atapi devices copy in x00 as the byte at offset 2. OK. So this is what a certain SCSI subset, the subset we call ATAPI, should do for this command? If T10 does not recognize this subset then what does that mean? >Ansi T13 had no comment on what this means, last I checked. Again T13 doesn't have anything to do with SCSI command sets. For SCSI devices using the ATA/ATAPI interface as the SCSI physical transport layer, T13 only defines the ATA/ATAPI physical transport and PACKET command protocol. >Ansi T10 says this is an op x12 Inquiry of up to x24 bytes. >(That's close to real - it should copy in x24 bytes always.) >Ansi T10 says x00 at offset 2 means the device "may or may not" >comply with any particular Ansi standard. OK. Sounds like a prefectly valid thing for T10 to say. >SFF says SFF-compliant devices shall put a x00 there. OK. I'm sure that is because SFF-8020 was an attempt by a few individuals to redefine SCSI to their way of thinking. I think we can safely say these people failed, SFF-8020 is now very obsolete. ATAPI device should be implemented according to the appropriate SCSI command set documents, such as MMC-x. That means such device would not be putting 0x00 in this Inquiry data byte. >I'd love to hear people evaluate this claim. Does anyone on >Earth know of Atapi devices that don't put a zero there? Don't know... Good question. *** Hale Landis *** www.ata-atapi.com ***
