Fujitsu M2488 Write Buffer Field Description, Write Buffer Modes, Mode Bits Implemented Modes

M2488 PRODUCT GUIDE								TAPE UNIT SCSI COMMANDS
						Table 4-129. WRITE BUFFER Field Description
	BYTE			BIT		VALUE		DESCRIPTION
		0		0-7		3Bh	Operation code.
		1		0-2			The Mode field is described in Table 4-130.
		2		0-7			The Buffer ID field identifies a specific buffer within the target.
		3-5					The Buffer Offset field specifies the offset in the buffer for the beginning of
							the data transfer. The Buffer Offset contains a multiple of the offset boundary
							specified in the offset boundary field of the READ BUFFER description.
		6-8					The Transfer Length specifies the maximum number of bytes transferred dur-
							ing the DATA OUT phase to be stored in the specified buffer beginning at the
							Buffer Offset. The transfer length must not exceed the capacity of the specified
							buffer. The capacity of the buffer is shown in Table 4-131.
						Table 4-130. WRITE BUFFER Modes
		MODE BITS
						IMPLEMENTED		MODES
	2		1		0
	0		0		0		No	Write combined header and data
	0		0		1		Yes	Vendor unique
	0		1		0		Yes	Write data
	0		1		1		No	Reserved
	1		0		0		Yes	Download Microcode
	1		0		1		Yes	Download Microcode and Save
						Support based on bit 3 (0x08) in FT4		1) Feature in FT4 disabled: Reserved.
	1		1		0	config. setting as described in M2488		2) Feature in FT4 enabled: Download microcode with
						User’s Guide.		offsets.
						Support based on bit 3 (0x08) in FT4		1) Feature in FT4 disabled: Reserved.
	1		1		1	config. setting as described in M2488		2) Feature in FT4 enabled: Download microcode with
						User’s Guide.		offsets and save.

Vendor Unique Mode (001b) and Write Data Mode (010b) Description. In these modes, the DATA OUT phase contains buffer data. The Buffer ID field identifies a specific buffer within the target. The supported buffer IDs for the vendor unique and write data modes are shown in Table 4-

131.Data transfer occurs only within the buffer area indicated by the buffer ID. If an unsupported buffer ID value is selected, the target returns CHECK CONDITION status and sets the sense key to ILLEGAL REQUEST with an additional sense code of ILLEGAL FIELD IN CDB.

April 1997 CG00000-011503 REV. A 4-145