Hitachi DK32EJ - Ultrastar Series 36.9 GB Hard Drive Reference Manual page 23

(2) Alternate Spare Area
The controller allocates 14 local alternate cylinders per notch as an Alternate
Spare Area for the defective sector.
(3) Defect Management
Defect management is the assignment of alternate spare sectors for defective
sectors caused by media flaws.
The host computer may access the data block as defect-free media by the defect
management.
The defect management consists of four schemes based on four defect sources as
shown below.
P scheme --- Defects identified by manufacturing process.
C scheme --- Defects detected by medium verification.
D scheme --- Defects specified by defect list of FORMAT UNIT command from the
G scheme --- Defects grown after manufactured.
The host computer may specify any combination of defect management schemes
with CDB ( Command Descriptor Block ) of FORMAT UNIT command and defect
list.
The controller uses P, C and G schemes as a default mode if the defect
management scheme is not specified ( i.e., CDB byte 1, Bit 4, FmtData = 0).
(4) Sector Interleave
In order to facilitate speed matching between host bus transfer rate and the disk
drive transfer rate, the sector interleave function allows formatting " Physical
Block ( sector ) " and "Logical Block " with a specified interval.
The Interleave value is specified by the CDB of the FORMAT UNIT command,
this controller supports sector Interleave factor (n=1) only.
(5) Track Skew
In order to avoid a rotational latency on the head switching, the controller
implements Track Skew which shifts the sector arrangement from each other
among tracks in the same cylinder.
2 PRODUCT SPECIFICATION OUTLINE
These defects are recorded in the system area as P list.
( Primary Defect list )
host computer.
These defects are detected by previous C and D scheme, and recorded
in the system area as G list. ( Grown Defect list )
OEM MANUAL:K6602771
Revision: 2 / Date: 2002.12.19
Page: 23 / 313