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4-39. OUTP'OT HELP INFORMATION (HELP)
The HELP command prints all of the command
names.
4-40. INITIALIZE MEDIA (INIT MEDIA)
The INIT MEDIA utility performs an initialization
routine on the disc drive. The INIT MEDIA utility
has a valid value of B, P, and I.
These values
correspond to the following;
B
=
Initializes the logic region. Spare table, spare
tracks, sector headers, and logs are left intact.
P
=
Initializes the logic region and field spares are
dealloca ted.
Factory spares and logs are
unchanged.
I
=
Initializes the entire drive. Logical tracks, spare
tracks, and maintenance tracks are cleared.
The spare table (factory and field spares) is
written back onto the maintenance tracks.
4-41. UPDATE DEVICE LOGS (PRESET)
The
PRESET
command
ca uses
all
recen t
information in controller RAM to be logged on the
disc maintenance tracks.
4-42. REQUEST STATUS (REQSTAT)
The REQSTAT utility sends a status message from
the device to the exerciser.
4-43. PERFORM READ-ONLY ERROR RATE
TEST (RO ER T)
The RO ERT command allows a sequential or
random read to take place in order to locate any
read errors.
4-44. OUTPUT RUN LOG (RUN LOG)
The RUN LOG command allows access to the run
log which contains an accumulation of all read
errors
which
were
found
during
run
time.
Run-time data errors are accumulated until the
log is cleared using the CLEAR LOGS command.
Service Information
7942 and 7946
4-45. SPARE (SPARE)
The SPARE utility physically relocates a track to
an address which is reserved for sparing.
4-46. OUTPUT SPARE TABLE (SPARE TABLE)
The
SP ARE
TABLE
command
accesses
the
information in the spare table.
4-47. OUTPUT DEVICE TABLE (TABLES)
The TABLES command accesses the tables stored
internally within the device in order to determine
the operational status of the device.
4-48. PERFORM SERVO TEST (SERVO)
The SERVO test checks the operation of the servo
system. An exha usti ve sequence of seeks is executed
verifying the subsequent location as well as
monitoring the speed performance.
The entire
sequence of seeks is repeated six times.
4-49. SET UNIT NUMBER (UNIT)
The UNIT utility allows the user to select the unit
number to be addressed within the device. The disc
drive is unit O.
4-50. PERFORM WRITE-THEN-READ ERROR
RATE TEST (WTR ERT)
The WTR ER T command writes a predefined data
pattern over a specified area of the disc, then reads
all data which was written.
4-51. TROUBLESHOOTING
When troubleshooting the disc drive, the first thing
to do is to determine if the fault is repeatable or
intermittent. A repeatable fault usually causes the
same self -test fail result to be presented each time
self test is performed. An intermittent fault, on
the other hand, occurs at random intervals, and
may not always cause a self -test failure.
In the case of a repeatable fault, self test will
identify the failing FRA with a 95 percent
certainty. In the event that more that one FRA is
listed as the possible cause of the failure, replace
the FRA's, one at a time, in the order given in the
self -test display.
4-11
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