M2488 PRODUCT GUIDE TAPE UNIT SCSI COMMANDS
April 1997 CG00000-011503 REV. A 4-59
Block Descriptor:
The block descriptor specifies the medium characteristics for all of a logical unit. The block
descriptor contains a density code of 00h or 09h (default), a number of blocks, and a block length.
Page Descriptor:
Table 4-56. Block Descriptor
BITS DEFAULT
BYTES 7 6 5 4 3 2 1 0
0Density Code = 09h 09h
1-3 Number of Blocks = 000000h 000000h
4Reserved 00h
5-7 Block Length 00h
Table 4-57. MODE SELECT Parameter Header Field Description
BYTE BIT VALUE DESCRIPTION
0 0-7 00h, 09h Density codes of 00h and 09h (default) create tapes in the format described
by ANSI standard X3B5/94-043.
Density Code 28h is described in CHAPTER 5.
1-3 000000h The number of blocks field is always set to zero, indicating that any
remaining logical blocks of the logical unit have the medium characteris-
tics specified by the block descriptor.
5-7 00h The block length specifies the length in bytes of each logical block
described by the block descriptor. A block length of zero indicates the
length is variable.
Table 4-58. Page Descriptors
BITS
BYTES 7 6 5 4 3 2 1 0
0PS Reserved Page Code
1Additional Page Length
2 - N Page Defined or Vendor Unique Parameter Bytes