HP 7936 Support Manual page 136

Troubleshooting and Diagnostics
7936 and 7937
RUN LOG
SDCLEAR
SERVO
SPARE
SPARE TABLE
TABLES
UNIT
WRITECACHEOFF
WRITECACHEON
WRITE LOG
WRTERT
8-14
Table 8-1. External Exerciser Commands (4 of 4)
Each head returns up to 106 entries. The format for the Error Code Byte
returned with each log entry is shown in figure 8-2. (Refer to paragraph
8-13 for more information concerning the run time log.)
No device-specific information.
The drive performs a "butterfly" seek on the specified head(s). This test
performs all possible length seeks in both directions (2808 seeks). The test
can be run on an individual head or all heads. If all heads are selected, each
head (starting with 0) completes a butterfly seek before the next sequential
head begins its seeks. If a fault occurs during the test, the drive logs the
fault and continues with the next length seek. Drive status and the fault log
provide information concerning the results of the test.
The test takes approximately 1 minute for each head tested.
No device-specific information.
The spare table is generated at power-on and stored in controller RAM.
Any spares added since power-on are included in the table. Because the
spare table is volatile. the drive always returns zero as the "number of
secondary spares" value.
The only tables supported are the spare track table and the cache table
(7936XP/7937XP drives).
The drive is addressed as unit O. The controller is individually addressable as
unit 15.
7936XP /7937XP drives only.
7936XP/7937XP drives only.
7936XP/7937XP drives only
No offset is allowed when performing an WTR ERT. The format for the
printed error information is defined in the details for the ERT LOG
command.