Sony DDS-4, Product Description Manual

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6 - 62 SONY SDT-10000/SDT-11000 DDS Tape Drive
6. COMMAND SPECIFICATION
Bit 7 6 5 4 3 2 1 0
Byte
0 BOP EOP Reserved BPU Reserved
1 Partition Number
2 Reserved
3 Reserved
4 (MSB)
7
First Block Location
(LSB)
8 (MSB)
11
Last Block Location (00 00 00 00h)
(LSB)
12 Reserved
13 (MSB)
15
Number of Blocks in Buffer (00 00 00h)
(LSB)
16 (MSB)
19
Number of Bytes in Buffer (00 00 00h)
(LSB)
The READ POSITION data shown below shall be returned during the DATA IN phase of the command.
READ POSITION Data Short Format, Short Form
BOP:
A beginning of partition (BOP) bit of one indicates that the logical unit is at the beginning-of-partition in the current
partition. A BOP bit of zero indicates that the current logical position is not at the beginning-of-partition.
EOP:
An end of partition (EOP) bit of one indicates that the logical unit is positioned between early-warning and end-of-
partition in the current partition. An EOP bit of zero indicates that the current logical position is not between early-
warning and end-of-partition. Note that this bit is mutually exclusive with the BOP bit.
BPU:
A block position unknown (BPU) bit of one indicates that the First and Last Block Locations are not known or
cannot be obtained. A BPU bit of zero indicates that the First contains valid position information. Support for this
option of the READ POSITION command is indicated by a BIS bit set to one in the MODE SELECT Device
Configuration page.
Partition Number:
Reports the current partition number for the current logical position.
First block location:
Indicates the Block Address associated with the current logical position. The value shall indicate the Block Address
of the next data block to be transferred between the initiator and the target if a READ or WRITE command is issued.
See BT field for description of Logical Block Address. Note that the Logical Block Address at BOT/P is 0.
READ POSITION