25 read buffer command, Read buffer command – Seagate Fibre Channel Interface User Manual
Page 284
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Fibre Channel Interface Manual, Rev. D
12.25
Read Buffer command
The Read Buffer command is used in conjunction with the Write Buffer command as a diagnostic function for
testing disc drive memory and the integrity of the FC-AL. This command will not alter the medium. Command
format is shown in Table 175.
Field definitions (listed alphabetically)
Allocation Length
The number of bytes available for returning read buffer command data.
Buffer ID
0
Control
See Control Bytes in Section 11.2.1.6.
Buffer Offset
0
Mode
The interpretation of data bits 0–2 is given in the following table and in paragraphs following the table.
Bit 2
Bit 1
Bit 0
0
0
0
Read combined descriptor header and data (Section 12.25.1)
0
1
0
Read data (Section 12.25.112.25.2)
0
1
1
Read descriptor (Section 12.25.312.25.1)
Table 175: Read Buffer command (3Ch)
Bit
Byte
7
6
5
4
3
2
1
0
0
0
0
1
1
1
1
0
0
1
0
0
0
0
0
Mode
Reserved
2
Buffer ID
3
(MSB)
4
Buffer Offset
5
(LSB)
6
(MSB)
7
Allocation Length
8
(LSB)
9
Control
3Ch
Table
number