Quantum DLT 2000, Руководство по эксплуатации продукта

Страница: 190 / 345

DLT2000 SCSI Interface
8-44 DLT2000/DLT2700 Cartridge Tape Subsystem
Parameter Block for Parameter Codes 02 through 09
Bit
7 6 5 4 3 2 1 0
0
(MSB)
Parameter Code
1
(LSB)
2 DU DS TSD ETC TMC Rsvd LP
3 04h
Byte 4
(MSB)
5 Counter Value
6
7
(LSB)
Figure 8-28 Read/Write Bytes Transferred LOG SENSE Page Format
Parameter Control Byte
•
DU–Disable Update: This bit is always zero.
•
DS–Disable Save: Saving parameters is not supported; this bit will always be set to
1.
•
TSD–Target Save Disable: Saving parameters is not supported; this bit will always
be set to 1.
•
ETC–Enable Threshold Comparison: Threshold checking is not supported on this
page; this bit is always a zero.
•
TMC–Threshold Met Criteria: Always a zero.
•
LP–List Parameter: This bit will always be set to zero as we treat the parameter
codes as data counter.
Counter Value
These parameter codes provide a count of the number of bytes transferred since the
current tape cartridge was inserted or since the last time the counters were reset via a
MODE SELECT command.
Parameter codes 02 and 03 report the counts of bytes transferred from the tape drive to
the initiator. Parameter code 02 reports the number of full megabytes transferred.
Parameter code 03 reports the number of bytes less than a full megabyte that has been
transferred. Multiplying the counter returned for parameter 02 by 1,048,576 and then
adding the counter value returned for parameter 03 will give the actual total bytes
transferred to the initiator.