Quantum Instruments DLT 7000 manual Mode Page Descriptors, Mode Select Page Descriptor Data Format

SCSI Commands

MODE SELECT (6) / (10) Command (15h) / (55h) (continued)

Table 5–38 MODE SELECT Mode Parameter Block Descriptor - Field Descriptions

(continued)

Field Name	Description
Number of	This MODE SENSE field is sent = 0, indicating that all of the remaining logical blocks
Blocks	on the tape will have the medium characteristics specified by the block descriptor.
Block Length	This field specifies the length, in bytes, of each logical block transferred over the
	SCSI bus. A block length of 0 indicates that the length is variable (specified in the I/O
	command). Any value other than 0 indicates the number of bytes per block to use
	for READ, WRITE, and VERIFY commands that specify a “fixed” bit of 1 (i.e., fixed
	block mode) which also causes the transfer length in the command descriptor
	block to be defined as a block count. If fixed bit is not equal to 1, this field is
	ignored.

5.9.1.3 Mode Page Descriptors

Following the MODE SELECT command’s Mode Parameter Block Descriptor are the MODE SELECT pages, each of which sets a different device parameter. Each mode page has a 2-byte header that identifies the page code and indicates the number of bytes in that page.

Bit	7	6	5	4	3	2	1	0
Byte
0	PS (0)	0			Page Code
1				Additional Page Length
2 - n			Page-Defined or Vendor Unique Parameter List

Figure 5–36 MODE SELECT Page Descriptor - Data Format

5-72 Quantum DLT 7000 Tape System