F O R M A T Unit (04); Defect List - IBM DCAS-32160 - Ultrastar 2.1 GB Hard Drive Specifications

7.4 FORMAT UNIT (04)
Byte
7 6
0
1 LUN
2
3 (MSB)
4
5 VU = 0
Figure 50. F O R M A T UNIT (04)
The F O R M A T command performs a physical formatting of the file media. This includes handling of defec-
tive sectors, and the overwriting of all data areas with a constant data pattern. (Reserved areas of the media
are not affected by the F O R M A T command.)
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.
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 file manages two internal defect lists and one external. The primary defect list ("P"List) is
created at time of manufacture and cannot be altered. 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
O U T phase of the F O R M A T UNIT command.
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.
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 file.

7.4.1 Defect List

62
O E M Spec. of DCAS-34330/32160
Bit
5 4 3
Command Code = 04h
FmtData CmpList
VU = 0
Interleave Factor
Reserved = 0
2 1 0
Defect List Format
(LSB)
FLAG LINK