Fujitsu M2488 manual Write Buffer command 3Bh, 32.1WRITE Buffer CDB Description

TAPE UNIT SCSI COMMANDS M2488 PRODUCT GUIDE

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).

4-3.32.1WRITE 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
4
								Buffer Offset
5
														LSB
6
		MSB
7
							Transfer Length
8
														LSB
9
					Reserved							Flag		Link

Note: Changeable fields in the CDB are shaded.

4-144 CG00000-011503 REV. A April 1997