Write Buffer (3B); Combined Header And Data (Mode 000B) - IBM DDRS-39130 - Ultrastar 9.1 GB Hard Drive Specifications

7.38 WRITE BUFFER (3B)

Byte
7 6
0
1 LUN
2
3 (MSB)
4
5
6 (MSB)
7
8
9 VU = 0
Figure 120. WRITE B U F F E R (3B)
The WRITE B U F F E R command is used in conjunction with the RE AD B U F F E R command as a diag-
nostic function for testing the file's memory and the SCSI bus integrity. This command does not alter the
medium of the file. Additional modes are provided for downloading microcode and for downloading and
saving microcode.
This command will cause the entire cache to be emptied.
The function of this command and the meaning of fields within the command descriptor block depend on
the contents of the mode field.
MODE Description
000 Write combined header and data
010 Data
100 Download Microcode
101 Download Microcode and Save
- All other modes are not supported by the file.

7.38.1 Combined Header And Data (Mode 000b)

In this mode, the data to be transferred is preceded by a four-byte header.
Buffer ID must be zero.
command is terminated with CHECK CONDITION status. And File shall set sense key to ILLEGAL
REQUEST and additional sense code to ILLEGAL FIELD IN CDB.
154
O E M Spec. of DDRS-3xxxx
Bit
5 4 3
Command Code = 3Bh
Reserved = 0
Buffer ID
Buffer Offset
Parameter List Length
Reserved = 0
If another value is specified, no download function are performed and the
2 1 0
Mode
(LSB)
(LSB)
FLAG LINK