Sony SDX-800V, SDX-800V/R

6.Command Specification MODE SELECT

6-40 SONY AIT-3Ex drive SDX-800V series Ver.1.1

Block length: The Block Length field specifies the length in bytes of each logical block transferred over the SCSI

bus. A block length of ZERO indicates that the length is variable. Any other value indicates the number of bytes per

block that the drive must handshake over the bus. This establishes block length such that the transfer length for

read, write type commands will be a block count not a byte count.

Note: It is value of this field together with the Fixed Bit Field in the READ, or WRITE commands that determine

whether the drive is in Fixed or Variable block mode.

Mode Fixed Bit in Read, Write Block Length in

Mode Select/Sense

Fixed Block

Variable Block

Block Size

The default fixed block size is 0 bytes however, if a fixed command (fixed bit of ONE) is received, the drive will return

the CHECK CONDITION status with an ILLEGAL REQUEST sense key and the additional sense code shall be set

to COMMAND SEQUENCE ERROR.

Note: Minimum block-size is 4. The figures must be multiples of 4, otherwise CHECK CONDITION status will be

return, and Sense Key will be ILLEGAL REQUEST.

Following the Block Descriptor are the MODE SELECT pages. They are the method by which the device parameters

are set. Each page has a two byte header which identifies the page code and indicates the number of bytes in that

page.

Table 6-38: MODE SELECT Page Header

Bit

Byte

7 6 5 4 3 2 1 0

0 PS Reserved Page Code

1 Additional Page Length

PS: when the Page Savable bit is set, this indicates that the page contains saved parameters. This bit will never be

set as there is no non-volatile RAM on the drive into which parameter data may be saved.

The page codes that are supported are:

Table 6-39: Supported MODE SELECT Page Codes

Page Code Description

00h

02h

0Ah

0Fh

10h

11h

1Ch

31h

32h

33h

3Fh

Standard Sense

Disconnect-Reconnect

Control Mode Page

Data Compression Control

Device Configuration

Medium Partitions Parameter

Information Exception Control

AIT Device Configuration

Append Partition (not support)

Delete Partition (not support)

Return All Pages

Additional Page Length: Indicates the number of bytes in that page. The value does not, however, include bytes 0

and 1. The length is returned on MODE SENSE and must subsequently be set to the same value when performing

MODE SELECT.

If the page length does not match that expected by the drive a CHECK CONDITION status is returned with the sense

key to set to ILLEGAL REQUEST.

The drive also returns a CHECK CONDITION status with an ILLEGAL REQUEST sense key if the Host sends an

unsupported Page Code, a page field with values that are not supported or are not changeable. In this case, no

parameters will have been changed by the command.