Quantum Instruments DLT 7000 - Manual (Page 138)

SCSI Commands
5-34 Quantum DLT 7000 Tape System
LOG SELECT Command (4Ch) (continued)
5.7.1 Log Detection Summary in LOG SELECT Command Descriptor Block
The following conditions constitute errors that are detected by the drive in
relation to the CDB. The request sense data is set to ILLEGAL REQUEST,
INVALID FIELD IN CDB.
The conditions that constitute errors are:
• PCR bit is set to 1 and parameter list is not set to 0.
• SP bit is set to 1
• A parameter list length that would cause a parameter within a valid page to
be truncated or otherwise incompletely initialized.
5.7.2 Operation of LOG SELECT
The LOG SELECT command allows the initiator to modify and initialize
parameters within the logs supported by the tape drive.
There are two ways to initialize the log parameters.
1. Set the PCR bit in the LOG SELECT CDB; this clears all parameters.
2. Specify the log page and parameter values as the log parameters to clear
individual pages. The following pages can be cleared using this method:
Page Code Page Description
02h Write Error Count Page
03h Read Error Count Page
32h Compression Ratio Page
If multiple pages are sent during the DATA OUT phase, they must be sent in
ascending order according to page code. Otherwise, the command terminates
with a CHECK CONDITION status, sense key set to ILLEGAL REQUEST, and
additional sense code set to INVALID FIELD IN PARAMETER LIST. The same
status is returned if an unsupported Page Code appears in any header or if the
specified page cannot be cleared.