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Mode sense (10) command (5ah) (continued) – Quantum 10K II User Manual

Page 179

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SCSI Description

5–112

Quantum Atlas 10K II Ultra160/m SCSI Hard Disk Drives

MODE SENSE (10) COMMAND (5Ah) (continued)

Bit

Byte

7

6

5

4

3

2

1

0

0

Density Code

1 - 3

(MSB)

Number of Blocks

(LSB)

4

Reserved

5 - 7

(MSB)

Block Length

(LSB)

Figure 5–49 Mode Parameter Block Descriptor — Data Format

Table 5–51 Mode Parameter Header & Block Descriptor — Field Descriptions

Data Field

Description

Mode Data Length

Reserved. Must be 0.

Medium Type

Ignored by the drive.

Device Specific Parameter Ignored by the drive.
Block Descriptor Length

The value = 0 if no Block Descrptor is supplied; the length is 8 if a block
descriptor is supplied.

Density Code

Ignored by the drive.

Number of Blocks

The value in this field specifies the number of logical blocks on the unit
that are affected by the current MODE SELECT command. When this field
= 0, the MODE SELECT parameters are put into effect for all logical
blocks on the unit. The maximum value allowed is the total number of
initiator-addressable logical blocks for the value specified in the Block
Length field. A value that is less than the maximum value will decrease
the number of initiator-accessible logical blocks to the amount specified.

Block Length

The value in this field specifies the length, in bytes, of each logical block.