Specifications
ATAPI For Streaming Tape QIC-157 Rev B
82
Table 6-60 Read Position Data Format
Bit
Byte
7 6 5 4 3 2 1 0
0 BOP EOP Reserved BPU Reserved
1 Partition Number
2 Reserved
3 Reserved
4 (MSB)
5 First Block Location
6
7 (LSB)
8 (MSB)
9 Last Block Location (Optional)
10
11 (LSB)
12 Reserved
13 (MSB)
14 Blocks in Buffer (Optional)
15 (LSB)
16 (MSB)
17 Bytes in Buffer (Optional)
18
19 (LSB)
A Beginning Of Partition (BOP) bit of one indicates that the Device 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.
An End Of Partition (EOP) bit of one indicates that the Device 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.
Implementor's Note: The BOP and EOP indications are not necessarily a result of a physical tape
marker (e.g., reflective marker or hole).
A Block Position Unknown (BPU) bit of one indicates that the block location is not known or cannot
be obtained. A BPU bit of zero indicates that the block location field contains valid position
information.
The Partition Number field reports the partition number for the current logical position. If the Device
only supports one partition for the medium, this field shall be set to zero.
The First Block Location field indicates the block address associated with the current position. This
value shall indicate the block address of the data block to be transferred between the Host and the
Device if a READ or WRITE command is issued.
The Last Block Location field indicates the block address associated with the next block to be
transferred from the buffer to the medium. The value shall indicate the block address of the next data
block to be transferred between the buffer and the medium. If the buffer does not contain a whole
block of data or is empty, the value reported for the Last Block Location shall be equal to the value
reported for the First Block Location.
The Blocks in Buffer field indicate the number of blocks that are in the Device buffer. Following a