TASK SET FULL Definition(s) in FC-TAPE and SAM-2
JoeBre at Exabyte.COM
JoeBre at Exabyte.COM
Wed Mar 17 08:38:40 PST 1999
* From the T10 Reflector (t10 at symbios.com), posted by:
* JoeBre at Exabyte.COM
> -----Original Message-----
> From: Dave Peterson [mailto:dap at nsg0.network.com]
> Sent: Tuesday, March 16, 1999 1:36 PM
> To: t10 at symbios.com; fc at nsg0.network.com
> Subject: TASK SET FULL Definition(s) in FC-TAPE and SAM-2
> Howdy All,
> FC-TAPE currently states in clause 9.2 for TASK SET FULL:
> - TASK SET FULL (if Tagged Queuing is used or ULP resources are
> SAM-2r10 states in clause 5.2:
> TASK SET FULL. This status shall be implemented if the logical unit
supports the creation
> of tagged tasks (see 4.9). This status shall be returned when the logical
unit receives a
> command and does not have enough resources to enter the associated task in
the task set.
> SAM-2r10 states in clause 4.8:
> A Task Set is composed of zero or more Untagged Tasks or a combination of
zero or more
> Tagged Tasks and zero or more Untagged Tasks.
> So it seems to me TASK SET FULL should be implemented regardless.
I am unclear as to what information TASK SET FULL conveys that BUSY does
not, in the case that Tagged Queing is not implemented. I would therefore
prefer that a target not be required to implement TASK SET FULL in this
Accordingly, perhaps 9.2 should say:
- TASK SET FULL (if Tagged Queuing is implemented)
> Another issue: what is the proper SCSI Status to return if:
> a) the lun does not support tagged tasks, is processing a command received
|from one Initiator (has no reservation active), has enough resources to
receive another command and enter it into the Task Set,
> and receives another command from a different Initiator.
> My preference would be a BUSY.
Shouldn't the lun just go ahead and process the new command from the other
intiator (queue it for execution)? Isn't it the responsibility of the
initiators to Reserve the lun if they are doing something that can be
disturbed by another initiator?
> b) the lun does not support tagged tasks, is processing a command received
|from one Initiator (has no reservation active), does not have enough
resources to receive another command and enter it into the
> Task Set, and receives another command from a different Initiator.
> I would expect a TASK SET FULL.
As outlined above, I would expect a BUSY.
> Dave Peterson phone : 612-391-1008
> Principal Engineer
> StorageTek Network Business Group email: dap at network.com
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