Quantum DLT1/VS80 SCSI, Interface Manual

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Chapter 4: SCSI Commands
4-86 July 2004 81-81276-01 Rev A01
4.12 READ (08h)
The READ command transfers one or more data blocks to the initiator starting with the next block on
the tape drive.
Figure 4-57.
READ (08h) Command Descriptor Block — Data Format
Bit
Byte
7 6 5 4 3 2 1 0
0 Operation Code (08h)
1 Logical Unit Number Reserved SILI Fixed
2 - 4
(MSB)
Transfer Length
(LSB)
5 Unused Reserved Flag Link
Table 4-52.
READ (08h) Command Descriptor Block — Field Descriptions
Field Name Description
LUN Logical Unit Number. The target ignores this field. Only an IDENTIFY message
can change the LUN.
SILI Suppress Incorrect Length Indicator. If the SILI bit is 1 and the fixed bit is 1, the
target terminates the command with CHECK CONDITION status and the Sense
Key set to ILLEGAL REQUEST with an Additional Sense Code of INVALID
FIELD in CDB.
If the SILI bit is not set and the actual block length is different from the specified
transfer length, the tape drive returns a CHECK CONDITION status. Within the
Sense data, the Incorrect Length Indicator (ILI) bit and Valid bit are 1. The Sense
Key field is NO SENSE. The Information Bytes are set to the difference (residue)
between the requested transfer length and the actual block length, or in Fixed
Blocked Mode, the difference (residue) between the requested number of blocks
and the actual number of blocks read. No more than Transfer Length bytes are
transferred to the initiator and the medium is logically positioned after the block
(EOM side).