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7. ATAPI Packet Command Specification
7.21. SPACE 11h
Bit
7
Byte
0
1
2
(MSB)
3
4
5
6
7
8
9
10
11
The SPACE command is used to position to a relative filemark or to end of data depending on the Count and
Code. Both forward and reverse filemark positioning are provided.
When spacing over filemarks, the Count field specifies the number of filemarks to be spaced over in the current
partition. A positive value N in the Count field shall cause forward positioning (toward end-of-partition) over N
filemarks ending on the end-of-partition side of the last filemark. A zero value in the Count field shall cause no
change of logical position. A negative value - N (two's complement notation) in the Count field shall cause reverse
positioning (toward beginning-of-partition) over N filemarks ending on the beginning-of-partition side of the last
filemark.
If end-of-data is encountered while spacing over filemarks, "Check Condition" status shall be returned, the Sense
Key shall be set to BLANK CHECK, and the Valid bit shall be set to one in the sense data. Additionally, the EOM
bit shall be set to one if end-of-data is encountered at or after early-warning. The Information field shall be set to
the difference (residue) of the requested count minus the actual number of filemarks spaced over.
If the end-of-partition is encountered while spacing forward over filemarks, "Check Condition" status shall be
returned, the Sense Key shall be set to MEDIUM ERROR, the EOM bit shall be set to one, and the Valid bit shall
be set to one. The Information field shall be set to the difference (residue) of the requested count minus the actual
number of filemarks spaced over.
If beginning-of-partition is encountered while spacing over filemarks in the reverse direction, "Check Condition"
status and the Sense Key to NO SENSE shall be set. The EOM and Valid bits shall be set to one, and the
Information field set to the total number of filemarks not spaced over (the requested number of filemarks minus the
actual number of filemarks spaced over).
When spacing to end-of-data, the count field is ignored. Upon successful completion, the medium shall be
positioned such that a subsequent write operation would append to the last logically recorded information.
If end-of-partition is encountered while spacing to end-of-data, "Check Condition" status shall be returned, the
Sense Key shall be set to MEDIUM ERROR, the EOM bit shall be set to one, and the Valid bit shall be set to zero.
7-72
6
5
4
Operation Code (11h)
Reserved
Table 7-60: Space Code
Code
000b
001b
011b
100b
101b-111b
3
2
Count
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Description
Blocks
Filemarks
End of Data
Setmarks
Reserved
SONY AIT-1 Turbo drive SDX-470V series Ver.1.0
SPACE
1
0
Code
(LSB)
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