Command Queuing and SAM
Charles Monia 09-Feb-1994 1633
monia at starch.enet.dec.com
Wed Feb 9 13:32:47 PST 1994
> Subject: Time: 2:55 PM
> OFFICE MEMO Command Queuing and SAM Date: 2/8/940
>Is it required by SAM that any SCSI protocol support all of the traditional
>queuing functions (e.g. head of queue, ordered, abort, clear queue, etc...). ?
>It would be a goodness if only unordered queuing and some abort function (reset
>anyone) be required.
>The reason I am opening this is because of ATA command queuing, where I want to
>develop a very simple solution. Functions other than unordered are either
>useless or can be emulated by the host (i.e. just send down commands one at a
>time for ordered commands). This simplification should help in making queuing
>easier for ATA implementations.
>Feedback is appreciated.
The following is my personal opinion on the issue:
Although support for queuing is still optional in SCSI-3, SAM requires
that all SCSI-3 devices which implement queuing support all forms as well as
the specified task management functions.
BTW: I would question why ATA should be bound by the rules that apply to SCSI-3.
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