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On Fri, 14 Dec 2001 15:28:23 -0800, Eschmann, Michael K wrote: >Now, error like this on an ATAPI drive should be followed by a Request >Sense, or is there anything else (like a reset) that ATAPI devices need? Now Michael, there you went and did it! Once again you have stepped into a giant black hole of ATAPI lack of specifications. Here nothing in SFF-8020 or ATA/ATAPI-x will help you. This really should get fixed... I have forgotten how many times I have attempt to get someone to talk about this. Here goes... 1) If the host issues a PACKET command (cmd code A0H) to a device and the device reports an error BEFORE the command packet is sent, then the error is an ATA error, there should be no change in the SCSI status of the drive and no Request Sense should be needed. What kind of error is this? Perhaps the host has requested DMA data transfer and the device does not support DMA. This is an physical interface error, it has nothing to do with the attempted SCSI command (the device has not even seen a SCSI command so how can it have any meaningful SCSI error information to report?). 2) Any PACKET command that ends with an error AFTER the command packet has been sent to the device MUST have an appropriate SCSI error code (SK, ASC, ASCQ) and the host should retrieve that information using a Request Sense command. Note that this includes any U-DMA data transfer ICRC errors. 3) If an ATAPI device fails an ATA command, such as SET FEATURES or one of the power management commands then there should be no change in the SCSI status of the device. No Request Sense is needed because (like 1 above) the device never did see a SCSI command, how can there be a SCSI error code to report? I know of lots of ATAPI devices that operate differently for reasons I can not explain. For example, they will ERR=1 ABRT=1 some invalid ATA command code correctly (try cmd code 00H) and then for no good reason have some strange Unit Attention error that must be cleared by Request Sense. This makes no sense at all!!! There is no reason for a Unit Attention error, there was no SCSI command failure!!! Now anyone want to try to fix the ATA/ATAPI standards? *** Hale Landis *** [EMAIL PROTECTED] *** *** Niwot, CO USA *** www.ata-atapi.com *** Subscribe/Unsubscribe instructions can be found at www.t13.org.
