Execute Internal Diagnostics Function; Read Drive Specific Information (Bus Control 43) - Seagate ST8741J Maintenance Manual

Testing IPI Interface Drives
If an error is detected in any test. testing stops and the
appropriate error and status codes are reported. If all tests
run error-free. the drive will be ready and the actuator will
be at cylinder zero with head zero selected.
Execute Internal Diagnostics Function
Receipt of this function runs an access test. a head select
test. and a read/write test.
The access test performs the following operations:
• Return to zero seek operation
•
•
Single track seek
Servo recalibrate
• Maximum seek
• Random seek
Successful completion of this test allows starting of the Head
Select test provided the Disable Write/Read Diagnostic bit is
not set. The Head Select and Write/Read tests can be disabled
by issuing the Disable Read/Write Diagnostics Function Code.
The Head Select test performs a seek to the diagnostic
cylinder. waits for on-cylinder. and then sequentially selects
all heads on the cylinder. Successful completion of this test
allows starting of the Write/Read test.
The write and read tests run if the drive is Ready. is not
write protected. and no fault conditions exist. If the drive
is write protected. it will run only the access and read
tests. The header is read and verified on the diagnostic
cylinder. If no errors are found. data patterns are written on
the diagnostic cylinder. after which they are read back and
verified.
Read Drive Specific Information {Bus Control 43)
The Read Drive Specific Information bus control transfers
status information to the controller. This status information
fits into two general categories:
• Native-controlled status -- generated by the Control
MPU. Although the codes are numerically different. they
report the information available via the status/control
panel.
• Interface-controlled status -- generated by the I/O MPU.
83325720 E
TROUBLE ANALYSIS
2-55