Exception handling78
HP restricted
5. Parallel SCSI only:
Allow the System Supervisor or support person to perform a controlled hard
SCSI Bus Reset.
If the
LOGICAL UNIT RESET Task Management function fails to clear the problem, the System
Supervisor or technical support person should be able to perform a controlled hard SCSI Bus
Reset as follows:
• Lock other users out cleanly.
• Go to a minimal-system single-user mode.
• Close all applications.
•Execute a hard SCSI Bus Reset.
The process should
not require a complete shutdown and reboot of the system.
Monitoring the condition of the drive and media
Through TapeAlert, an HP LTO Ultrium tape drive constantly monitors the condition of the
mechanism and media, and presents the results in a form that host software can readily use and
users can easily understand.
You can find a general description of TapeAlert in the diagnostics section of the User Guide.
Supporting TapeAlert
HP has refined the TapeAlert standard to include the Predictive Failure flag. If the drive sets this flag,
the host should display a message that the drive is “about to fail and should be replaced”. There
should be no impact on ISV software if the TapeAlert standard is already fully supported.
NOTE: Reading the TapeAlert log clears all the flags, as defined in the TapeAlert specification.
The TapeAlert Log page consists of 64 flags that indicate potential problems with the drive, and that
allow host software to suggest appropriate corrective action to the user. For example, if Flag 20
(“Clean Now”) is set, the software should advise the user to clean the tape heads.
The drive maintains both SSC and ADC TapeAlert flags because the two standards state different
clearing conditions.
• The drive maintains separate copies of the SSC TapeAlert flags for each port. These are only
cleared when a port retrieves its TapeAlert flags with a LOG SENSE command with page code
2Eh, provided the TAPLSD (TapeAlert Prevent LOG SENSE Deactivation) mode parameter is zero
in the Device Configuration Extension mode page.
• The drive also maintains a set of ADC TapeAlert flags, which are shared by each port. The ADC
TapeAlert flags are not cleared when a port retrieves them with a LOG SENSE command with
page code 12h.
See Chapter 4 of Volume 3, SCSI Interface, of the HP Ultrium Technical Reference Guide for details
of the TapeAlert log page.
