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6.Command Specification
6.7. MODE SELECT 15h
Bit
7
Byte
0
1
Logical Unit Number
2
3
4
5
Unused (00b)
MODE SELECT enables the Host to configure the drive. Similarly MODE SENSE enables the Host to identify which
configuration parameters the drive supports and what its current configuration is. Implementing MODE SELECT
and MODE SENSE requires a certain amount of "handshaking" between the Host and the drive. Before configuring
the drive, the Host should issue a MODE SENSE. This allows the drive to return its current configuration and
indicate what parameters are configurable. The Host interprets this information and may then issue a MODE
SELECT command to set up the drive to the Host's preferred configuration.
Note: In the MODE SELECT and MODE SENSE (operation code 1Ah) descriptions much of the information
overlaps and therefore the two descriptions should be read in conjunction.
MODE SELECT allows the initiator to specify configuration parameters to the drive.
The drive always powers-up with its default configurations set. This is also true, if the drive receives a BUS DEVICE
RESET message or a hard reset through the RST line on the SCSI bus.
PF: The Page Format bit indicates that the data sent by the Host after the MODE SELECT header and block
descriptors complies with the definition of pages as set out in SCSI-2.
SP: The Save Parameters bit instructs the drive to save all savable pages. This bit is not supported and the drive will
return a CHECK CONDITION status with an ILLEGAL REQUEST sense key, if it is set.
Parameter List Length: This specifies the length, in bytes, of the MODE SELECT parameter list that is transferred
during the DATA OUT phase. A ZERO parameter list length indicates that no data is transferred. The Parameter List
length must be a value which coincides with header, block descriptor or page boundaries. If this does not occur then
the drive will return a CHECK CONDITION status with an ILLEGAL REQUEST sense key set.
The MODE SELECT parameter list shown below, contains a four-byte header, followed by one eight-byte block
descriptor.
Bit
7
Byte
0
1
2
Reserved
3
4
5
(MSB)
6
7
8
9
(MSB)
10
11
Buffered Mode: Buffered Mode is the mechanism by which the drive implements Immediate Reporting on WRITE
commands.
6-40
6
5
4
Operation Code (15h)
PF
Parameter List Length
Table 6-31: MODE SELECT parameter list
6
5
4
Buffered Mode
Block Descriptor Length (08h)
Number of Blocks (00 00 00h)
3
2
Reserved
Reserved
Reserved
Reserved
3
2
Reserved
Reserved
Density Code
Reserved
Block Length
SONY AIT-3 drive SDX-700 series Ver.2.1
MODE SELECT
1
0
SP (0)
Flag
Link
1
0
Speed (00h)
(LSB)
(LSB)
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