Table A-14: Pad Bit And Cat Bit Interaction - Spectra Logic Spectra S50 User Manual

Table A-14: PAD Bit and CAT Bit Interaction

SRC PAD DST PAD CAT
1 0 0
X 1 0
X X 1
0 0 0
The Descriptor Length provides the length in bytes of the current segment descriptor.
The length is defined as the actual length of the descriptor minus four. The Descriptor
Length does not include any embedded data where applicable. The Descriptor Length
field is verified for the descriptor type, and, if it is not correct, the copy manager sets a
CHECK CONDITION. The Sense Key is set to ILLEGAL REQUEST, and the ASC and ASCQ indicate
INCORRECT DESCRIPTOR LENGTH.
The Source and Destination Target Identifiers specify the indexes into the Target
Descriptors (see Target Descriptors on page 85). For some segment descriptors, either
the Source Target Identifier or Destination Target Identifier is not applicable; in those
cases, the field should be coded as 0.
If the target addressed by the Target Identifier index is not accessible to the copy
manager then the command terminates with a CHECK CONDITION. The sense key is set to
COPY ABORTED with an ASC and ASCQ of UNREACHABLE TARGET.
The maximum number of segment descriptors permitted within a parameter list is
defined by the copy manager's Maximum Segment Count parameter on its Mode Sense
page 0Eh. If the number of segment descriptors exceeds the number established
through the Mode Sense value, then the copy manager sets a CHECK CONDITION. The sense
key is set to ILLEGAL REQUEST, and the ASC and ASCQ indicate TOO MANY SEGMENT DESCRIPTORS.
In general, the specific commands issued by the copy manager to execute the segment
descriptors is implementation-dependent. Data must be moved from the source devices
to the destination devices in a manner that is consistent with the segment descriptors;
the movement must always results in the destination device being at a deterministic
state when any intermediate or final status is returned.
Appendix A. Extended Copy—83h—143r1 Specifications
Copy Manager Action
On inexact segments, the copy manager strips input characters from the final source
block(s), always stopping at the end of a complete block.
On inexact segments, the copy manager adds PAD characters (0h) to the destination
block to completely fill the block.
The copy manager always writes or reads complete blocks. On inexact segments, the
remainder of the block contains data from the next segment. If this code is set on the
last segment of the EXTENDED COPY command, the command terminates with a
CHECK CONDITION; the sense key is set to COPY ABORTED, and the ASC and ASCQ are
set to UNEXPECTED INEXACT SEGMENT.
On inexact segments, this will be an error. The command terminates with a CHECK
CONDITION; the sense key is set to COPY ABORTED, and the ASC and ASCQ are set to
UNEXPECTED INEXACT SEGMENT.
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