User Manual

SCSI Commands Reference Manual, Rev. J 400
www.seagate.com Parameters for direct access devices
SWP (Software Write Protect) bit
1 A software write protect (SWP) bit set to one specifies that the logical unit shall inhibit writing to the medium after writing all cached or
buffered write data, if any. When SWP is one, all commands requiring writes to the medium shall be terminated with CHECK CONDITION
status, with the sense key set to DATA PROTECT, and the additional sense code set to WRITE PROTECTED. When SWP is one and the
device type's command standard defines a write protect (WP) bit in the DEVICE-SPECIFIC PARAMETER field in the mode parameter
header, the WP bit shall be set to one for subsequent MODE SENSE commands.
0 A SWP bit set to zero specifies that the logical unit may allow writing to the medium, depending on other write inhibit mechanisms
implemented by the logical unit. When the SWP bit is set to zero, the value of the WP bit, if defined, is device type specific. For a list of
commands affected by the SWP bit and details of the WP bit see the command standard for the specific device type.
RAERP, UAAERP, and EAERP bits
NOTE These three bits have been declared obsolete by the T10 committee and are not supported.
RAERP (Ready AER Permission) bit (obsolete)
1 A Ready AER Permission (RAERP) bit of one specifies that the target may issue an asynchronous event report upon completing its initial-
ization sequence instead of generating a unit attention condition.
0 A RAERP bit of zero specifies that the target shall not issue an asynchronous event report upon completing its initialization sequence.
UAAERP (UNIT ATTENTION AER Permission) bit (obsolete)
1 A UNIT ATTENTION AER Permission (UAAERP) bit of one specifies that the target may issue an asynchronous event report instead of cre-
ating a unit attention condition upon detecting an unit attention condition event (other than upon completing an initialization
sequence).
0 A UAAERP bit of zero specifies that the target shall not issue an asynchronous event reporting instead of creating a unit attention condi-
tion.
Table 381 Unit attention interlocks control (UA_INTLCK_CTRL) field
Code Definition
00b
The logical unit shall clear any unit attention condition reported in the same I_T_L_Q nexus transaction as a CHECK CONDITION
status and shall not establish a unit attention condition when a task is terminated with BUSY, TASK SET FULL, or RESERVATION
CONFLICT status.
01b
Reserved
[a]
10b [a]
The logical unit shall not clear any unit attention condition reported in the same I_T_L_Q nexus transaction as a CHECK CONDI-
TION status and shall not establish a unit attention condition when a task is terminated with BUSY, TASK SET FULL, or RESERVA-
TION CONFLICT status.
11b [a]
The logical unit shall not clear any unit attention condition reported in the same I_T_L_Q nexus transaction as a CHECK CONDI-
TION status and shall establish a unit attention condition for the initiator port associated with the I_T nexus on which the BUSY,
TASK SET FULL, or RESERVATION CONFLICT status is being returned. Depending on the status, the additional sense code shall be
set to PREVIOUS BUSY STATUS, PREVIOUS TASK SET FULL STATUS, or PREVIOUS RESERVATION CONFLICT STATUS. Until it is
cleared by a REQUEST SENSE command, a unit attention condition shall be established only once for a BUSY, TASK SET FULL, or
RESERVATION CONFLICT status regardless to the number of commands terminated with one of those status values.
[a] A REQUEST SENSE command still clears any unit attention condition that it reports.