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What happened to the text that described how ATAPI devices handle SRST.
Yes please, I'm curious too - what happened?
It used to be that ATAPI devices would do the SRST handshake but not reset,
and also preserve DSC (except DSC is now obsoleted).
Now the only text is a clause that reads that SRST should not be sent while
a
packet command is active because some packet devices will continue with
the command.
I trust we all agree,
ATAPI commands have two kinds of active.
There is the while BSY|DRQ activity, same as ATA, but then there is also the background activity reported by DSC. An op xA0:2B Immediate "Seek", an op xA0:04 Immediate "Format", and op xA0:1B Immediate "Start" or "Stop" or "Load" or "Eject" ... all that background stuff should proceed despite an SRST getting received by an ATAPI device because the SRST was sent to an ATA device, but was received by the ATAPI device accidentally because the SRST was broadcast without a DEV bit to say which device should receive it.
New commands, such as an op xA0:00 "Test Unit Ready" and an op xA0:03 "Request Sense", are the polling mechanisms completely normal since SCSI 2 that definitely should arrive while background activity continues.
The ATAPI use of DSC appeared first in SFF 8020i as a redundant means of indicating background activity in progress. Various massively distributed hosts came to depend on that convenient redundancy.
PL
