M2488 PRODUCT GUIDE TAPE UNIT SCSI COMMANDS
April 1997 CG00000-011503 REV. A 4-145
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 Table4-
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 I N CDB.
Table 4-129. WRITE BUFFER Field Description
BYTE BIT VALUE DESCRIPTION
00-7 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 Mod es
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
1 1 0 Support based on bit 3 (0x08) in FT4
config. setting as described in M2488
User’s Guide.
1) Feature in FT4 disabled: Reserved.
2) Feature in FT4 enabled: Download microcode with
offsets.
1 1 1 Support based on bit 3 (0x08) in FT4
config. setting as described in M2488
User’s Guide.
1) Feature in FT4 disabled: Reserved.
2) Feature in FT4 enabled: Download microcode with
offsets and save.