Sony SDX-1100V/R manual Sequential-Access Density Codes Code Value, Command Sequence Error

6.Command Specification MODE SELECT

Density Code: The supported values for the density code field are defined in the following table.

Table 6-40: Sequential-Access Density Codes

Code Value		Code Value
30h	AIT-1	Format (not support)
31h	AIT-2	Format (not support)
32h	AIT-3	Format
B3h	AIT-3Ex	Format
33h	AIT-4	Format
34h	AIT-5	Format
7Fh	No change from previous density

Number of Blocks: A MODE SENSE field which will be returned as ZERO, indicating that all of the remaining logical blocks on the media will have the medium characteristics specified by the block descriptor, or until a subsequent MODE SELECT command changes those parameters. This field must be set to ZERO on a MODE SELECT otherwise a CHECK CONDITION status will be returned with an ILLEGAL REQUEST sense key.

Block length: The Block Length field specifies the length in bytes of each logical block. 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	1	Block Size
Variable Block	0	0

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 ASC will 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 returned with an ILLEGAL REQUEST sense key.

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 6-41: MODE SELECT Page Header

Bit	7	6	5	4	3		2	1	0
Byte
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.

6-42 SONY AIT-5 drive SDX-1100V series Ver.1.0