CDB Control Byte, bits 6&7
Duncan Penman
penman at netcom.com
Thu Oct 6 21:31:13 PDT 1994
In response to my note about tracking CD-ROM ATAPI commands in
SCSI-3, Debbi Ast of NCR wrote:
I would like to make a suggestion in response to the
proposed changes to the SCSI-3 CD-ROM command set. I
would also like to see the READ TOC command updated in
SCSI-3 with a 2 bit format field. Many SCSI CDROM vendors
(Sony, Matsushita, Hitachi...) have already added a 2 bit
format field in the READ TOC command(byte 9, bits 6 & 7) to
support multisession discs. For compatibility, it would be
nice to define this same location in the SCSI-3 spec. Are
there any implications with using this location? Is this
how it is mapped in the ATAPI version?
Debbi Ast
NCR Microelectronics
debbi.ast at ftcollinsco.ncr.com
In SCSI-2, these 2 bits are defined as vendor-specific. Quite reasonable
for the CD-ROM drive manufacturers to use in this way. The ATAPI mapping
is direct..byte 9 of the CDB to byte 9 of the Command Packet. The
question in this is, Can we define a SCSI vendor-specific field to
have a specific meaning for one device type?
Would appreciate a bit of strategic guidance here before getting too
deep into implementation alternatives.Received: from cc:Mail by CCMSMTP2.FTCollinsCO.NCR.COM
id AA780266292; Thu, 22 Sep 94 13:28:09 MDT
Date: Thu, 22 Sep 94 13:28:09 MDT
Message-Id: <9408227802.AA780266292 at CCMSMTP2.FTCollinsCO.NCR.COM>
To: Duncan Penman <penman at netcom.com>, scsi at WichitaKS.NCR.COM,
atapi at dt.wdc.com
Subject: Re: Tracking ATAPI CD-ROM Cmds in SCSI-3
Status: RO
Duncan Penman
Zadian Technologies
penman at netcom.com
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