Log Sense; Command Descriptor Block - Seagate Viper 200 Scsi Interface Manual

Lto tape drive
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Page 42

LOG SENSE

Command Descriptor Block

Field Descriptions
The Log Select and Log Sense commands work in conjunction to allow the host to
control and obtain statistical information about cartridge usage and error rates. This
information consists of counters of particular events.
Log Sense data is obtained by specifying a log page in the Page Code field of the
Log Sense CDB. The host can request only one page of data with each Log Sense
command. The available pages are found by reading the Supported Log Pages Log
(00h).
Bits
Byte
7
0
1
Ignored LUN
2
PC
3
4
5
6
7
8
9
Field
Bytes
Bits
Operation
0
Code
Ignored
1
5-7
Logical
Unit
Page
2
6-7
Control
(PC)
Page
2
0-5
Code
Parameter
5-6
7-0
Pointer
6
5
4
Operation Code (4Dh)
Page Code
Reserved
Reserved
Parameter Pointer, MSB
Parameter Pointer, LSB
Allocation Length, MSB
Allocation Length, LSB
Description
The Operation Code for Log Sense is 4Dh.
The LUN field is residual from the SCSI-1 days and is ignored.
00b = Requests Threshold values (always returns maximum possible
values).
01b = Requests Accumulated values
10b = Requests Default threshold values (always returns maximum
possible values).
11b = Requests Default accumulated values (always returns 0s).
00h = Requests Supported Log Pages Log
02h = Requests Write Error Counters Log
03h = Requests Read Error Counters Log
0Ch = Requests Sequential Access Device Log
2Eh = Requests Tape Alert Log
30h = Requests Tape Usage Log
31h = Requests Tape Capacity Log
32h = Requests Data Compression Log
Specifies the beginning parameter code to be returned to the initia-
tor. All remaining parameter codes are returned in ascending order.
This field is ignored for page code 00h.
LTO SCSI Interface Manual
3
2
1
Reserved
Control
0

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