User Manual

SCSI Commands Reference Manual, Rev. J 218
www.seagate.com Direct Access Block commands (SPC-5 and SBC-4)
PF (page format) bit
1 A page format (PF) bit set to one specifies that the SEND DIAGNOSTIC parameters and any parameters returned by a following RECEIVE
DIAGNOSTIC RESULTS command with the PCV bit set to zero shall contain a single diagnostic page as defined in 5.1.1.
0 A PF bit set to zero specifies that all SEND DIAGNOSTIC parameters are vendor specific. If the PARAMETER LIST LENGTH field is set to zero
and the SEND DIAGNOSTIC command is not going to be followed by a corresponding RECEIVE DIAGNOSTIC RESULTS command with the
PCV bit set to zero, then the application client shall set the PF bit to zero. The implementation of the PF bit is optional.
SELFTEST (Self-test) bit
1 A self-test (SELFTEST) bit set to one specifies that the device server shall perform the logical unit default self-test. If the self-test success-
fully passes, the command shall be terminated with GOOD status. If the self-test fails, the command shall be terminated with CHECK
CONDITION status, with the sense key set to HARDWARE ERROR.
0 A SELFTEST bit set to zero specifies that the device server shall perform the diagnostic operation specified by the SELF-TEST CODE field
or in the parameter list. The diagnostic operation may require the device server to return parameter data that contains diagnostic
results. If the return of parameter data is not required, the return of GOOD status indicates successful completion of the diagnostic oper-
ation. If the return of parameter data is required, the device server shall either:
a) Perform the requested diagnostic operation, prepare the parameter data to be returned and indicate completion by returning GOOD
status. The application client issues a RECEIVE DIAGNOSTIC RESULTS command to recover the parameter data; or
b) Accept the parameter list, and if no errors are detected in the parameter list, return GOOD status. The requested diagnostic operation
and the preparation of the parameter data to be returned are performed upon receipt of a RECEIVE DIAGNOSTIC RESULTS command.
UNITOFFL (unit offline) bit
1 A unit offline (UNITOFFL) bit set to one specifies that the device server may perform diagnostic operations that may affect the user
accessible medium on the logical unit (e.g., write operations to the user accessible medium, or repositioning of the medium on sequen-
tial access devices). The device server may ignore the UNITOFFL bit.
0 A UNITOFFL bit set to zero specifies that, after the device server has completed any diagnostic operations specified by the SEND DIAG-
NOSTIC command, the user accessible medium shall exhibit no effects resulting from the device server’s processing the SEND DIAGNOS-
TIC command that are detectable by any application client. When the SELFTEST bit is set to zero, the UNITOFFL bit shall be ignored.
DEVOFFL (SCSI target device offline) bit
1 A SCSI target device offline (DEVOFFL) bit set to one grants permission to the device server to perform diagnostic operations that may
affect all the logical units in the SCSI target device (e.g., alteration of reservations, log parameters, or sense data). The device server may
ignore the DEVOFFL bit.
0 A DEVOFFL bit set to zero specifies that, after the device server has completed any diagnostic operations specified by the SEND DIAG-
NOSTIC command, no logical unit shall exhibit any effects resulting from the device server’s processing the SEND DIAGNOSTIC com-
mand that are detectable by any application client. If the SELFTEST bit is set to zero, the DEVOFFL bit shall be ignored.
PARAMETER LIST LENGTH field
The PARAMETER LIST LENGTH field specifies the length in bytes of the parameter list that shall be transferred from the application client
Data-Out Buffer to the device server. A parameter list length of zero specifies that no data shall be transferred. This condition shall not be con
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sidered an error. If PF bit is set to one and the specified parameter list length results in the truncation of the diagnostic page (e.g., the parame-
ter list length does not match the page length specified in the diagnostic page), then the command shall be terminated with CHECK
CONDITION status, with the sense key set to ILLEGAL REQUEST, and the additional sense code set to INVALID FIELD IN CDB.
To ensure that the diagnostic command information is not destroyed by a command sent from another I_T nexus, the logical
unit should be reserved.