RE: [Q] simple question about a Task.

[Charles Monia <cmonia@NishanSystems.com>]

Hi:

I believe the requirement in SAM-2 is that only one command may be "pending"
for a task at any time.  That is, the initiator may not send the next in a
sequence of linked commands until it receives a status  of INTERMEDIATE or
INTERMEDIATE-CONDITION met for the pending command.

In my opinion, therefore, the scenario you describe should result in an
error condition. Trying to send a new CDB using the same tag while another
command with that tag is pending should cause the task to be terminated with
a CHECK COINDITION status.

Charles
> -----Original Message-----
> From: Kim Tae-Hyung [mailto:kotaeji@pilots.postech.ac.kr]
> Sent: Friday, November 17, 2000 8:38 PM
> To: ips@ece.cmu.edu
> Subject: [Q] simple question about a Task.
> 
> 
> 
> Hi. I have a very basic question about iSCSI.
> 
> I know A SCSI Task is a SCSI command or possibly a linked set of SCSI
> commands.  This means that one task may consist of several SCSI
> commands. 
> 
> And the "Initiator Task Tag" uniquely identifies the task in iSCSI. 
> 
> Here, let's assume that a task consists of three SCSI READ CDBs. And
> initiator sends three iSCSI SCSI Command(0x01) corresponding to each
> SCSI READ CDB. Three iSCSI SCSI command PDU MUST have same 'Initiator
> Task Tag'fields, because they belong to the same Task.
> 
> And, some time later, a SCSI Data (READ) PDU arrived at initiator. How
> can the initiator know which SCSI Command this data PDU belongs to ?
> I cannot find any field in SCSI Data (READ) PDU which can make me
> happy. 
> 
> Thanks in advance.
>