Seagate Ultra160 Product Manual page 172

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Table 84: Relationship of BQUE and CMDQUE bits
BQue CmdQue
0 0
0 1
1 0
1 1
[25] VS. vendor-specific bit.
[26] The VENDOR IDENTIFICATION field contains eight bytes of ASCII data identifying the vendor of the
product. The data shall be left aligned within this field.
Note. It is intended that this field provide a unique vendor identification of the manufacturer of the SCSI
device. In the absence of a formal registration procedure, T10 maintains a list of vendor identifica-
tion codes in use. Vendors are requested to voluntarily submit their identification codes to T10 to
prevent duplication of codes (see Annex D). For Seagate drives, the Vendor Identification field con-
tains the ASCII data giving vendor name ("SEAGATE").
This bit was formerly used for SOFT RESET.
[27] The PRODUCT IDENTIFICATION field contains ASCII data giving the drive model number. The data shall
be left-aligned within this field.
[28] The PRODUCT REVISION LEVEL field contains the four bytes of ASCII data "XXXX," where the value of
"XXXX" is determined by each device manufacturer.
[29] PRODUCT DESCRIPTION field. In some models (SACI-2), this field contained the Drive Serial Number
field, containing the 8 bytes of ASCII data "XXXXXXXX," where the value XXXXXXXX is the drive serial
number. In newer models it's use is vendor-specific.
[30] Vendor-specific.The area from byte 44 through byte 55 are vendor-specific.
[31] Reserved.
[32] CLOCKING. The CLOCKING field shall not apply to asynchronous transfers and is defined in Table 85.
Table 85: Clocking field
Code Description
00b Indicates the device server supports only Single Transition (ST)—the latching of data only on the assertion
edge of the REQ(ACK) signal.
01b Indicates the device server supports only Double Transition (DT)—the latching of data on both the assertion
edge and the negated edge of the REQ(ACK) signal.
10b Reserved.
11b Indicates the device server supports ST and DT.
[33] QAS. A Quick Arbitrate Supported (QAS) bit of one indicates that the device server supports the quick
arbitrate feature. A value of zero indicates that the device server does not support the quick arbitrate fea-
ture.
[34] IUS. Information Unit Supported.
[35] Copyright Notice field. This field contains 48 bytes of ASCII data "Copyright (c) XXXX Seagate All rights
reserved," where "XXXX" indicated the current year.
[36] VERSION DESCRIPTOR 2 through 8 (bytes 60-71). The VERSION DESCRIPTOR fields provide for iden-
tifying up to eight standards to which the device claims conformance. The value in each PAGE OR OPER-
ATION CODE field shall be selected from Table 57 of SCSI Primary Commands-2 (SPC-2), T10/1236D.
All version descriptor values not listed in Table 57 are reserved. Technical Committee T10 of NCITS main-
tains an electronic copy of the information in Table 57 on its world wide web site (http://www.t10.org/). In
the event that the T10 world wide web site is no longer active, access may be possible via the NCITS
world wide web site (http://www.ncits.org) or the ANSI world wide web site (http://www.ansi.org). It is rec-
Description
No command queuing of any kind supported.
Command queuing with all types of task tags supported.
Basic task set model supported (see SAM-2).
Illegal combination of BQue and CmdQue bits.
SCSI Interface Product Manual, Rev. B