This message is from the T13 list server.
Mark Overby wrote:
This message is from the T13 list server. I have an ATAPI DVD drive that is < 3 months old that exhibits this behavior. (Actually I have two, both from different manufacturers)
Wow... Badly broken devices. I wonder if the ATAPI people that make these things will ever "get it right"? They have had 8+ years - I think it is about time they "got it right"!
Conveniently, since I have the host and interrupt controller under my chipset I can probe both lines. The INTRQ line on the ATA interface fires, the interrupt fires in the chipset, and then the status is read with BSY still asserted and the INTRQ becomes unasserted again. I'll dig out the hard drive I have that exhibits this behavior, I don't remember how old it was.
Broken devices. But they probably work on most systems (especially x86 and Windows) because of the extremely high "interrupt processing" overhead - by the time the x86 reads the Status register it has BSY=0.
Hale
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++ Hale Landis ++ www.ata-atapi.com ++
