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3.4.3
WRITE BUFFER (3B)
Bit
Byte
0
1
2
3
4
5
6
7
8
9
This command is used in combination with the READ BUFFER command to diagnose the
normality of the IDD's data buffer memory or the SCSI bus, or to download microcode to the
IDD.
The IDD stores data transferred from the INIT in accordance with the specifications in this
command's CDB to in the data buffer in the IDD. The IDD has 512 K (524,288) byte data
buffers. This command, using buffer addresses with a range of X '000000' to Cache segment
volume – 2, must specify data storage positions in each buffer in 2-byte units, and with even
numbered addresses. The INIT can know the IDD's buffer configuration and the units which
addresses can be specified in by issuing the READ BUFFER command.
The functions of this command and the format of data transferred from the INIT are specified
in the "Mode" field in byte 1 of the CDB and any of the transfer modes shown below can be
selected.
"Mode Bit"
7
6
5
LUN
Buffer Address (MSB)
Buffer Address
Buffer Address
Buffer Address (LSB)
Transfer Byte Length (MSB)
Transfer Byte Length
Transfer Byte Length (LSB)
0
0
0
2
1
0
0
0
0
Header + Data, without Address Specification
0
0
1
Header + Data, with Address Specification
0
1
0
Data Only, with Address Specification
1
0
0
Microcode Download, without Saving
1
0
1
Microcode Download, with Saving
C141-E039-01EN
4
3
2
X'3B'
0
0
0
0
0
Transfer Mode
1
0
Mode
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