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Chapter 4 SCSI Commands
VERIFY Command (13h)
DLT-S4 Interface Reference Guide
334
VERIFY Command (13h)
4
The
VERIFY
command directs the tape drive to verify one or more blocks
beginning with the next block on the tape. The drive verifies both CRCs
and EDCs.
Figure 169
VERIFY
Command
Descriptor Block
—
Data Format
Table 189
VERIFY
Command
Data
—
Field Descriptions
Bit
Byte
7
6
5
4
3
2
1
0
0
Operation Code (13h)
1
Reserved
Immed
BytCmp
Fixed
2 — 4
(MSB)
Verification Length
(LSB)
5
Control
Field
Description
Immed
Immediate. When set to 1, the
VERIFY
command completes, provided it has begun
processing, before the drive performs any tape medium movement.
BytCmp
Byte Compare. Must be set to 0.
Fixed
Specifies whether the drive is to verify fixed-length or variable-length blocks.
When set to 0, variable-block mode is requested. The drive verifies a single block with
the Verification Length specifying the block size.
When set to 1, the Verification Length specifies the number of blocks the drive is to
verify. This is valid only if the drive is currently operating in fixed-block mode.
Verification
Length
Specifies the amount of data to verify, in blocks or bytes, as indicated by the Fixed field.