Sony DDS-4, Руководство по описанию продукции

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6 - 32 SONY SDT-10000/SDT-11000 DDS Tape Drive
6. COMMAND SPECIFICATION
6. 07 MODE SELECT 15h
Bit 7 6 5 4 3 2 1 0
Byte
0 Operation Code (15h)
1 Logical Unit Number PF Reserved SP (0)
2 Reserved
3 Reserved
4 Parameter List Length
5 Unused (00b) Reserved
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 actually 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 (opcode 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. The drive expects this bit to be set, otherwise it returns
a CHECK CONDITION status with the sense key set to ILLEGAL REQUEST.
However, if the Parameter List Length is set to 12 bytes, i.e. the host only wishes to transfer the Parameter List
Header and a single Block Descriptor, the PF bit need not be set and the drive will return a GOOD status.
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 set 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.
MODE SELECT