Fujitsu MAS3367, MAP3367, MAP3147, MAS3735, MAP3735 specifications Read Buffer 3C, Lun

3.4 Maintenance, Diagnostic Commands

3.4.4 READ BUFFER (3C)

	Bit	7	6	5	4		3	2		1	0
Byte
0					X‘3C’
1			LUN		0				Mode
2				X‘00’ (Buffer ID)
3				Buffer Offset (MSB)
4				Buffer Offset
5				Buffer Offset		(LSB)
6				Transfer Byte Length (MSB)
7				Transfer Byte Length
8				Transfer Byte Length (LSB)
9		0	0	0	0	0		0		0	Link

This command is used in combination with the WRITE BUFFER command to diagnose the normalcy of the IDD’s data buffer memory and the SCSI bus.

The IDD have a 7680 K byte size data buffer.. In this command, each data byte position in the data buffer must be specified in 4-byte units using buffer addresses within the range X'000000' to X'77FFFF'.

The functions of this command and the contents of the data transferred to the INIT are specified by the “Mode” field in the CDB and one of the transfer modes shown below can be selected.

“Mode” Bit	3	2	1	0	Transfer Mode
	0	0	0	0	Header + Data, without Address Specification
	0	0	0	1	Header + Data, with Address Specification
	0	0	1	0	Data Only, with Address Specification
	0	0	1	1	Buffer Descriptor
	1	0	1	0	Echo buffer
	1	0	1	1	Echo buffer descriptor

(1)Mode = 0, 0, 0, 0: Header + data, without address specification

When this mode is specified, the data stored in the IDD’s data buffer are transferred to the INIT after the 4-byte header. Zero must be specified in the “Buffer offset” field in the CDB.

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