Fujitsu M2488, Руководство по эксплуатации продукта

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TAPE UNIT SCSI COMMANDS M2488 PRODUCT GUIDE
4-144 CG00000-011503 REV. A April 1997
4-3.32 WRITE BUFFER command 3Bh
The WRITE BUFFER command is used in conjunction with the READ BUFFER command as a
diagnostic function for testing target memory and the SCSI bus integrity. Additional modes are sup-
ported for downloading and saving microcode and writing data to NVRAM. All modes supported
involve the transfer of data from the initiator to the target. Other than synchronizing any buffered
write data to tape prior to performing the write buffer operation, this command does not alter tape
medium of the target.
Operational Note. For initiators which do not have enough memory space from which to send the
microcode image being downloaded with one WRITE BUFFER command in download microcode or
download microcode and save modes, it is possible to use multiple WRITE BUFFER commands
with the Mode of Write Data, incrementing the Buffer Offset appropriately, and then for the last
WRITE BUFFER command, request the Mode of Download Microcode or Download Microcode
and Save with the appropriate Buffer Offset and Transfer Length for the last portion of the microcode
being downloaded. This requires that the microcode being downloaded always be written into the
buffer starting at byte 0 (i.e. the first WRITE BUFFER command must have a Buffer Offset of zero).
4-3.32.1 WRITE BUFFER CDB Description
WRITE BUFFER is a ten-byte command. The bytes are shown below and described in Table 4-
129. Common fields are described in paragraph 4-3.1 on page 4-4.
BITS
BYTES 7 6 5 4 3 2 1 0
0 0 0 1 1 1 0 1 1
1 LUN Reserved Mode
2 Buffer ID
3 MSB
Buffer Offset 4
5 LSB
6 MSB
Transfer Length 7
8 LSB
9 Reserved Flag Link
Note: Changeable fields in the CDB are shaded.