Format Unit (04) - IBM Ultrastar 36LZX Specifications

8.4 FORMAT UNIT (04)

Byte
7 6
0
1 Reserved
2
3 (MSB)
4
5 VU = 0
Figure 50. FORMAT UNIT (04)
The FORMAT command performs a physical formatting of the drive media. This includes handling
defective sectors and overwriting all data areas with a constant data pattern. (Reserved areas of the
media are not affected by the FORMAT command.)
Ÿ FmtData set to one specifies that a Data Out phase follows the Command phase. FmtData set to
zero specifies that no Data Out phase follows.
Ÿ CmpList set to one specifies that the GList (Grown Defect List) existing prior to the format not be
used and is discarded. The drive is formatted with PList and DList (if specified). DList becomes the
new GList.
Note: The drive manages two internal defect lists and one external. The primary defect list ("P"List)
is created at time of manufacture. The grown defect list ("G"List) is built after manufacture by the
Initiators use of the REASSIGN BLOCK command and the Automatic Reallocate functions. The data
defect list ("D"List) is an external list. It is supplied by the initiator in the DATA OUT phase of the
FORMAT UNIT command.
Ÿ Defect List Format specifies the format of the defect descriptor transferred to the Target when
FmtData bit is set to one. The Target supports three defect descriptor formats for the Format Unit
command as following:
Format Description
000b Block format
100b Bytes From Index format
101b Physical Sector format
If the FmtData bit is set to zero, this field must also be zero. Otherwise the command will complete
with a check condition with a sense key of illegal request and an additional sense code of invalid
field in CDB.
Ÿ Interleave Factor may be zero or one, either of which specifies an interleave of 1:1. Other
Interleave Factors are ignored because of the extensive buffering implemented in the drive.
Bit
5 4 3
Command Code = 04h
FmtData CmpList
VU = 0
Interleave Factor
Reserved = 0
Ultrastar 36LZX hard disk drive specifications
2 1 0
Defect List Format
(LSB)
FLAG LINK
59