Technical information

HGST Ultrastar C15K600 Hard Disk Drive Specification
212
18.21
READ BUFFER (3C)
Table 178 READ BUFFER (3C)
Byte
Bit
7
6
5
4
3
2
1
0
0
Command Code = 3Ch
1
Reserved = 0
Mode
2
Buffer ID = 0
3-5
(MSB)
Buffer Offset
(LSB)
6-8
(MSB)
Allocation Length
(LSB)
9
VU = 0
Reserved = 0
FLAG
LINK
The READ BUFFER command is used in conjunction with the WRITE BUFFER command as a diagnostic function
for testing the memory of the drive and the SCSI bus integrity. This command does not alter the medium.
The function of this command and the meaning of fields within the command descriptor block depend on the
contents of the mode field.
MOD
Description
00000 Read Combined Header and Data
00010
Read Data
00011
Descriptor
01010
Read Data from Echo Buffer
01011
Echo Buffer Descriptor
11010
Enable Expander Communications Protocol and Echo Buffer
11100
Error History
All others Not supported