Nope, experimentally derived.
> > The Atlas drives also have a fixed maximum queue
> > depth of 32 commands, but will return QUEUE_FULL for conditions other than
>
> Hmmm ...
> I remember having read that the recommended queue depth for the Atlas II
> on AIX is 38.
The 32 for Atlas I drives is from Quantum tech support. If they recommend
38 on AIX it must be that AIX is really slow to send out commands. LAst I
heard, they only recommended 7 to 8 on Novell.
> I did get a try with an Atlas II using 64 tags and I remember it was
> capable to accept so many commands sometimes.
> The Viking II is documented as accepting a fixed maximum of 64 commands.
> Donnot know how it is supposed to behave in multi-initiator environment,
> but my guess is that this is also the maximum for the total amount of
> commands at any time and certainly not the maximum per initiator.
>
> > QUEUE_FULL if it simply isn't capable of taking another command at the
>
> A device can return QUEUE FULL status at any time when it receives a
> tagged command.
Sure, I'm not saying it can't. Just that some times a BUSY status instead
of QUEUE_FULL status would make more sense, but that Quantum doesn't use
BUSY at all as far as I can tell. It's their choice, since what they are
doing is legal by the spec, I just happen to think it's less intelligent
than it could be.
> The initiator has no handle on the thing which is stated
> to be full by the device. The SCSI specs are so about this status and are
> not going to change AFAIK.
>
> Gerard.
--Doug Ledford <dledford@dialnet.net> Opinions expressed are my own, but they should be everybody's.
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