168 Product Manual - Disc Drive SCSI-2/SCSI-3 Interface (Vol. 2; Ver. 2), Rev. E
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Table 5.2.1-31. Unit Attention Parameters (00h)
Bit
7
6
5
4
3
2
1
0
Byte(s)
0
PS
Page Code (0h)
1
0
0
0
0
0
0
0
1
Page Length (in bytes)
2
SSM
IL Unit-
Rnd Strict
DEFAULT
0 [1]
[2] Attn[3]
0 [4]
[5]
0
CHANGEABLE
[7]
3
DEFAULT
[6]
CHANGEABLE
[7]
Page zero is the last page to be reported by the drive.
Notes.
[1] If the enable Synchronous Select Mode (SSM) bit equals one, the drive initiates for WDTR and SQTR
messages when it recognizes that one may be required (after reset, reset msg. or power cycle). If the
SSM bit equals zero the drive does not initiate WDTR or SDTR regardless of negotiated conditions prior
to reset, reset message or power cycle.
[2] “Inquiry Length” (IL) bit. When the IL bit is set to 1, the standard INQUIRY data available to a host is
limited to the 36 bytes required by the SCSI-2 specification. When the IL bit is reset (0), 148 bytes of
standard INQUIRY data are available. The Additional Length field in byte 4 of the INQUIRY data is
updated to reflect the actual number of additional bytes available.
[3] When the Unit Attn bit is set to 1, then Unit Attention is logged in sense only; no Check Condition Status
is presented following any reset. When this bit is RESET (0) then Check Condition is presented for all
affected Initiators following a reset until Request Sense is issued by each Initiator (as per current opera-
tion).
[4] When the Round bit equals one, the drive treats and reports rounded parameters as described in Section
4.8. When Round equals zero the drive shall round the parameter and handle command completion
reporting as if the parameter had not been rounded.
[5] When the Strict bit is a one, the drive checks for Initiator attempts to change unchangeable parameters.
If the drive detects an attempt it rejects the command in the standard way, i.e., Check Condition status
from drive, Request Sense from the Initiator, Illegal Request sense key (5h) back from the drive. When
the Strict bit is zero, the drive ignores the values of the unchangeable parameters in a Mode Select
command. The drive does not reject the command trying to change unchangeable parameters.
[6] This byte is reserved for future compatibility with Seagate host adapters. Though presently may be
changeable, (see note [7]) this byte does not control anything, unless the individual drive Product Manual
indicates that it does and defines its use in the Mode Sense Data section.
[7] See individual drive Product Manual Mode Sense Data section for a table showing codes that indicate
which of these bits are changeable by the host using the Mode Select command.
