Write Buffer (3Bh); Write Data Mode - Dell PowerVault TL2000 Reference Manual

WRITE BUFFER (3Bh)

Write Buffer is used with Read Buffer as a diagnostic function for testing the device data buffer, DMA
engine, SCSI bus interface hardware, and SCSI bus integrity. Additional modes are provided for
downloading and saving micro code and updating Vendor Unique settings.
Bit 7
Byte
0
1
2
3 (MSB)
4
5
6 (MSB)
7
8
9
Field descriptions:
Mode: The Mode field is used to select the mode of operation. The media changer supports the following
values within this field.
0010b
0100b
0101b
1010b
If any non supported value is set, the media changer terminates the command with a Check
Condition status. The sense key will be set to ILLEGAL REQUEST and the sense data to INVALID
FIELD IN CDB.
Buffer ID:
When the Mode is set to Download micro code or Download micro code and save, the Buffer ID
should be set to zero. When the mode is set to Vendor Unique operation, the Buffer ID indicates
the requested page to update. If the value of the Buffer ID is not supported by the specified Mode
the command is rejected. The target detects and rejects commands that would overrun the buffer.
Buffer Offset:
The Buffer Offset is required for the Download micro code (and save) modes and optional for the
Vendor Unique and Data modes. In all other modes the Buffer Offset must be set to zero.

Write Data Mode

With this mode, SCSI bus integrity can be tested in conjunction with the READ BUFFER command. The
host can by means of this mode send up to 256 bytes to the media changer. This data can be retrieved by
means of the READ BUFFER command. The Buffer Offset specifies the offset within the buffer. Potential
buffer overruns are detected and will result into a Check Condition the sense key will be set to ILLEGAL
REQUEST and the additional sense data to INVALID FIELD IN CDB.
3-84
TL2000 and TL4000 SCSI Reference
6 5
Operation Code (3Bh)
LUN Reserved
Parameter list length
4 3
Buffer ID
Buffer offset
Control
Data
Download microcode
Download microcode and save
Echo buffer
2 1
Mode
(LSB)
(LSB)
0