SCSI Commands
Page
99
Field Descriptions
Field
Bytes
Bits
Description
Operation
Code
0
The Operation code for Request Sense is 03h.
Ignored
Logical
Unit
1
5-7
The LUN field is residual from the SCSI-1 days and is ignored.
Allocation
Length
4
Specifies the amount of data to be returned, in bytes.
Reserved
All reserved bits must be 0.
Control
5
See Control Byte Format on page 18.
Sense Data Format
The Request Sense command returns sense data in the following format.
Byte
Bits
7
6
5
4
3
2
1
0
0
Valid
Error Code
1
Segment Number
2
FM
EOM
ILI
Reserved Sense Key
3
Information, MSB
4
Information
5
Information
6
Information, LSB
7
Additional Sense Length
8
Command-specific Information, MSB
9
Command-specific Information
10
Command-specific Information
11
Command-specific Information, LSB
12
Additional Sense Code
13
Additional Sense Code Qualifier
14
Field-Replaceable Unit Code
15
SKSV
C/D
Reserved
BPV
Bit Pointer
16
Field Pointer, MSB
17
Field Pointer, LSB
18
Reserved
19
Reserved
20
Reserved
21
Reserved
CLN
Reserved
Field Descriptions
Field
Bytes
Bits
Description
Valid
0
7
0 = The Information field does not contain valid information
1 = The Information field contains valid information
This is always 0 for deferred errors.
Error Code
0
0-6
70h = A current error, associated with the most recent command.
71h = A deferred error, not associated with the current command.
Segment
Number
1
Always 0, because the Copy, Compare, and Copy and Verify com-
mands are not supported.
FM bit
2
7
1 = A Space, Read, or Verify command did not complete because a
file mark was read.
