Read block limits command (05h) (continued) – Quantum Instruments DLT 7000 User Manual

Page 236

Advertising
background image

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.

Advertising