Reference Guide

Chapter 4 SCSI Commands
SEND DIAGNOSTIC Command (1Dh)
DLT-S4 Interface Reference Guide 324
Table 179 SEND
DIAGNOSTIC Command Data
— Field Descriptions
Level 1 Test: Electronics
Test
4
Running a Level 1 test requires that a major portion of the controller
hardware and software be functioning properly. The Level 1 test is based
on the premise that full power-up testing is not necessary; therefore, it is
an extension of the power-on tests that the drive runs. The test verifies the
controller software Error Detection Code (EDC) and checks one queue
that much of the controller software uses by dequeuing and enqueuing
items. The test also runs a cache memory test. Finally, this test checks the
status of the servo subsystem by sending a
STATUS command to the servo
and interpreting the results.
The Level 1 test does not attempt a
WRITE or READ to or from the tape
medium. If an error occurs during the Level 1 test, the drive reports a
CHECK CONDITION status and reports any errors that occurred in the
extended Sense Data bytes.
The Level 1 test has an execution time of approximately 5 seconds. See
table 180
for information on setting the SEND DIAGNOSTIC CDB fields to
select a Level 1 test.
Level 2 Test: Write / Read
Functionality Test
4
The Level 2 test performs the following actions:
1 Writes two tracks of data, one in each direction.
2Rewinds the tape.
Field Description
PF Page Format. Must be set to 0 when the SelfTst bit is set
to 1.
Selftst Self Test. Used with DevOfl and UnitOfl to specify the
type of testing to be done (see table 180
for specific
information).
DevOfl Device Offline. Used with Selftst and UnitOfl to specify
the type of testing to be done (see table 180
for specific
information).
UnitOfl Unit Offline. Used with Selftst and DevOfl to specify the
type of testing to be done (see table 180
for specific
information).
Parameter
List Length
Indicates the number of bytes of parameter data that will
be sent to the drive. Must be 0 when the SelfTst bit is set
to 1.