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Commands 117
Commands
Returned Data—Long Read Position:
The format of the 32 bytes of data returned in long format for READ POSITION
is as follows:
Returned Data Fields:
Most of the fields are the same as for the Short format. The new fields are as
follows:
BPU Block Position Unknown
0 The First and Last Block Location fields are valid.
1 Block position is unknown. First and Last Block Location fields are undefined. This will
only occur after a “hard” read error that has caused a sense key of
MEDIUM ERROR with
additional sense of 3B00h (sequential positioning error).
Partition Number This will always be zero.
First Block
Location
The First Block Location specifies the number of blocks and filemarks to the current position.
Counting starts at zero, so BOM is block location 0.
Last Block
Location
This is always set to the value of the First Block Location.
7 6 5 4 3 2 1 0
0
BOP EOP Reserved (0) MPU BPU Reserved (0)
1
Reserved (0)
3
4
(MSB)
Partition Number (0)
7
(LSB)
8
(MSB)
Block Number
15
(LSB)
16
(MSB)
File Number
23
(LSB)
24
(MSB)
Set Number(0)
31
(LSB)