Quantum DLTtape DLT 7000, Product Manual

Page: 236 / 312

SCSI Commands
5-132 Quantum DLT 7000 Tape System
READ BLOCK LIMITS Command (05h) (continued)
In SCSI-3 configurations, Byte 0 appears as shown below:
0 Reserved Granularity
The Granularity field is described in the table below.
Table 5–62 READ BLOCK LIMITS Data - Field Descriptions
Field Name Description
Granularity (SCSI-3 Only) This field indicates the supported block size granularity. The DLT
7000 tape drive supports all block sizes
n such that n minus the
minimum block length limit is a multiple of 2 x (where x is the value in
the Granularity bits), and n is greater than or equal to the Minimum
Block Length Limit and less than or equal to the Maximum Block Size
Limit. For the DLT 7000 system, the content of the Granularity field is
1 (since block sizes must be a multiple of 2; 2
1
= 2).
For backward compatibility, the DLT 7000 will process requests that
do not meet Granularity criteria, except for Odd-byte Multiple Block
Fixed Block WRITE commands when connected to a Wide (16-bit)
SCSI bus.
Maximum Block Length The value in this field indicates the maximum block size. The tape
drive supports a maximum block length of 16,777,215 (16 MB-2) for
10, 20, or 35 GB format. A maximum block length of 256 K bytes is
supported for 2.6 GB or 6.0 GB formats.
Minimum Block Length The value in this field indicates the minimum block size. The tape
drive supports a minimum block length of 2 bytes.