>>>>> "Alan" == Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes:
I'm guessing Doug is out today because he didn't forward the note
below. Just passing the info along...
>> It is needed by the transport protocol(s).
Alan> I don't understand; can you explain more fully? Which transport
Alan> protocol(s) need to use the Sector Count? The USB transport
Alan> protocol doesn't; it encodes the transfer length in a wrapper.
Alan> The bridge chip should interpret the wrapper instead of looking
Alan> inside the SAT command.
Doug posted to the T10 list and here's what Jim Hatfield from Seagate
responded:
For ATA (SATA or PATA), the Count field should NEVER be zero,
because neither interface supports zero-length data transfer for
any protocol (dma, pio, etc).
In ATA, 'N/A' is defined the way it is because there are some
ancient implementations for which there are vendor specific
differences.
--
Martin K. Petersen Oracle Linux Engineering
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