
SCSI Commands
Quantum DLT 8000 Tape System 5-219
5.30 VERIFY Command (13h)
The VERIFY command directs the tape drive to verify one or more blocks beginning with
the next block on the tape. Both CRC and EDCs are validated.
Bit
Byte
7 6 5 4 3 2 1 0
0 Operation Code (13h)
1 Logical Unit Number Reserved Immed BC Fixed
2 - 4
(MSB)
Verification Length
(LSB)
5 Unused Reserved Flag Link
Figure 5–101 VERIFY Command Descriptor Block — Data Format
Table 5–100 VERIFY Command Data — Field Descriptions
Field Name Description
Immed Immediate. When set to 1, the VERIFY command completes before
any tape medium movement is done (that is, when the processing
has been initiated.
BC Byte Check. When set to 0, the tape drive performs an internal
CRC/ECC check of data. No data is transferred to the initiator.
When set to 1, the command is rejected.
Fixed This bit specifies whether fixed-length or variable-length blocks are to
be verified.
When set to 0, variable-block mode is requested. A single block is
transferred with the Verification Length specifying the maximum
number of bytes the initiator has allocated for verification.
When the Fixed bit is set to 1, the Verification Length specifies the
number of blocks to be verified. This is valid only if the logical unit is
currently operating in Fixed Block mode.
Verification Length This field specifies the amount of data to verify, in blocks or bytes as
indicated by the Fixed bit.
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