Appendix B: Eeprom-Resident Bugcheck And Event Logs - Quantum DLT 8000 Product Manual

Appendix B
EEPROM-RESIDENT BUGCHECK AND EVENT LOGS
This appendix provides an explanation of the event logs (information packets) stored in
semi-permanent, non-volatile memory of the tape drive. These packets can be retrieved
via the SCSI LOG SENSE command with Page Code 07h.
B.1 EEPROM Packets (LAST n EVENTS)
The tape drive keeps certain event logs in semi-permanent, non-volatile memory
(EEPROM, in this case) located on the tape drive's controller PCB. There is storage
enough within EEPROM for a total of 14 of these logs, or packets, each packet
consisting of 98 bytes (96 data bytes plus two control bytes) of information. Packets may
be written for different reasons and several packet types exist.
The information in the event logs does not indicate that a tape drive or tape medium has
failed but is useful in isolating problems that may be occurring.
The logs are maintained in a circular buffer: a new entry overwrites the oldest existing
entry. At any point in time, the most recent 14 logs are kept.
The EEPROM information packets can be retrieved via the SCSI-2's LOG SENSE
command with Page Code 07 (Last n Error Events Page).
The packet type field defines the content as well as the format of the data portion of the
packet. These packet types are detailed in this Appendix. Note that the byte offsets in
the structure layout diagrams are reference relative tot he beginning of the 98-byte
EEPROM log envelope.
Quantum DLT 8000 Tape System B-1