Table A-17: Segment Descriptor For Codes 03H And 0Eh - Spectra Logic Spectra S50 User Manual

The DC bit is used to indicate whether the Block Device Number of Blocks field refers
to the source or destination logical unit. A DC bit of 0 indicates that the Block Device
Number of Blocks field refers to the source logical unit. A DC bit of 1 indicates that the
Block Device Number of Blocks field refers to the destination logical unit.
The Source Block Device Logical Block Address provides the block address from
which the read of data will start. The Destination Block Device Logical Block Address
provides the block address at which the write operation will begin.
Stream Device to Stream Device Operation (Descriptor Code 03h)
The segment descriptor format for EXTENDED COPY transfers between two stream devices is
shown in Table A-17. This format is required for descriptor code 03h. The field
definitions for the first eight bytes are defined in Segment Descriptors on page 93.

Table A-17: Segment Descriptor for Codes 03h and 0Eh

Bit
Byte 7
0
1
2
3
4 (MSB)
5
6 (MSB)
7
8
9 (MSB)
10
11
12
13 (MSB)
14
15
Appendix A. Extended Copy—83h—143r1 Specifications
6 5 4
Descriptor Type Code (03h or 0Eh)
Reserved
Descriptor Length
Source Target Identifier
Destination Target Identifier
Source Device Transfer Length
Destination Device Transfer Length
3 2
Reserved
Reserved
Reserved
98
1 0
DC CAT
(LSB)
(LSB)
(LSB)
(LSB)