Subject: SCSI CDB bytes

From: "Trang Nguyen" <[email-masked]>
Date: Wed, 25 Jul 2001 18:35:02 -0400

Hello,

I have some questions about the SCSI CDB.

From the draft-ietf-ips-iscsi-07.txt:
    "2.3.6 CDB - SCSI Command Descriptor Block

        There are 16 bytes in the CDB field to accommodate the commonly used
        CDB.  Whenever the CDB is larger than 16 bytes, an Extended CDB AHS
        MUST is used to contain the CDB spillover. "

1.  The SCSI CDB field in the SCSI Command PDU is 16 bytes long.  Does it
mean that iSCSI supports SCSI-3?  I thought that iSCSI supports only SCSI-2
commands, and doesn't support SCSI-3 commands.

2.  If iSCSI supports SCSI-2 commands, then in which case the CDB is larger
16 bytes?

Thanks a lot,

*********************************
 Trang Nguyen
 [email-masked]
*********************************

---

From: "Dave Peterson" <[email-masked]>
Date: Wed, 25 Jul 2001 19:12:48 -0500

Not sure where you came up with SCSI-2.
Currently iSCSI refers to the SAM-2 architecture which implies support for
SCSI-3 command set.
New XOR commands defined in SBC-2 use 32 byte CDBs. Most OSD commnds (Object
Based Storage Device) are also > 16 bytes.

Dave

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
Trang Nguyen
Sent: Wednesday, July 25, 2001 5:35 PM
To: IPS
Subject: SCSI CDB bytes

Hello,

Thanks a lot,