TAPE UNIT SCSI COMMANDS M2488 PRODUCT GUIDE
4-124 CG00000-011503 REV. A April 1997
4-3.28 SEND DIAGNO STIC (FACT ORY MODE) comm and 1Dh
The SEND DIAGNOSTIC (FACTORY MODE) command requests the target to perform diagnostic
tests on itself, or on the attached periphera l devices. After the receipt of a val id SEND DIAG NOSTIC
command, the unit performs synchronization prior to execution of the SEND DIAGNOSTIC opera-
tion. Disconnection occurs, if allowed, during the execution of the function. When the self-test bit is
zero, this command is usually followed by a RECEIVE DIAGNOSTIC RESULTS command.
** NOTE **
The SEND DIAGNOSTIC command as described in this section
requires that the tap e drive be set in FA CTORY MODE.
4-3.28.1 SEND DIAGNOSTIC CDB Description
SEND DIAGNOSTIC is a six-byte command. The bytes are shown below and described in
Table 4-114. Common fields are described in paragraph 4-3.1 on page 4-4.
The following Field Description table specifies the use of each field of the SEND DIAGNOSTIC
CDB. Refer t o Table 4-115 in conjunction with the following table for a more concise overview of
how each field is used.
BITS
BYTES 7 6 5 4 3 2 1 0
00 0 0 1 1 1 0 1
1LUN PF Reserved Selftest DevOfL UnitOfL
2Reserved
3MSB Parameter List Length
4LSB
5Reserved Flag Link
Note: Changeable fields in the CDB are shaded.
Table 4-114. SEND DIAGNOSTIC (FACTORY MODE) Field Description
BYTE BIT VALUE DESCRIPTION
0 0-7 1Dh Operation code.
1 0 1 A UnitOfL (Unit Offline) bit of 1 enables write operations on user medium or opera-
tions that affect user visible medium positioning.
1 1 1 A DevOfL (Device Offline) bit of 1 enables diagnostic operations that may adversely
affect operations to other logical units on the same target.
1 2 1
0A Selftest bit of 1 directs the target to complete its default selftest.
A Selftest bit of 0 directs the target to perform tests defined by the bytes in the
parameter list. Successful completion of the function and preparation of a response is
indicated by presentation of GOOD status. The response is then recovered by execu-
tion of the RECEIVE DIAGNOSTIC RESULTS command.