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SCSI Interface Product Manual, Rev. B
Table 136:
MODE SELECT parameter list
Bit
7
Byte
0
0
0
1
0
2
3
BLOCK DESCRIPTOR LENGTH (either 0 or 8 decimal) [2]
0
DENSITY CODE or NUMBER OF BLOCKS (MSB) [3] [4]
1
NUMBER OF BLOCKS (MSB) [3] [4]
2
NUMBER OF BLOCKS [4]
3
NUMBER OF BLOCKS (LSB) [4]
4
0
5
BLOCK LENGTH (MSB) [5]
6
BLOCK LENGTH [5]
7
BLOCK LENGTH (LSB) [5]
0-n
MODE SELECT PAGE HEADERS AND THEIR PARAMETERS (Tables 137 and 138)
[1]
The MEDIUM TYPE field shall be 00h to define the default type direct access device.
[2]
The BLOCK DESCRIPTOR LENGTH specifies the length in bytes of the Block Descriptor. It is equal to
the number of bytes in the Block Descriptor (either 0 or 8) and does not include the page headers and
mode parameters. A BLOCK DESCRIPTOR LENGTH of zero indicates that no block descriptors shall be
included in the parameter list. This condition shall not be considered an error.
[3]
a. For drives that do not support capacity programming, the DENSITY CODE shall be 00h to define the
default density of medium.
b. If the drive supports capacity programming (see note [4]), byte 0 may be useable as MSB part of the
number in bytes 1, 2, and 3, if the drive's capacity capability requires it. For drives whose programmed
capacity or maximum designed capacity does not require the use of byte 0, byte 0 will always be 00h.
(See also note [4b]).
[4]
a. For drives that do not support capacity programming, these bytes are always zero.
b. A capacity value greater than the product or customer defined maximum but less than the drive's phys-
ical maximum will result int he drive taking the specified capacity. Any request that is beyond the phys-
ical maximum will result in an ILLEGAL REQUEST. The product-defined maximum is the drive's default
capacity and can be determined by setting bytes 0, 1, 2, and 3 to 0xFFFFFFFF.
[5]
BLOCK LENGTH specifies the length in number of bytes for each logical block described by the Block
Descriptor. Set to desired sector size before a Format. (Valid values are even numbered sizes from 180 to
4096. Not all drives can format down to 180; some have a minimum of 256).
[6]
See MODE SENSE command (Section 8.12) for detailed descriptions of the MODE SELECT/Sense
pages.
6
5
0
0
0
0
MEDIUM TYPE [1]
0
0
Block Descriptor
0
0
Parameter Information [6]
4
3
0
0
Reserved
0
0
0
0
Reserved
0
0
2
1
0
0
0
0
0
0
0
0
193
0
0
0
0
0
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