HP C2233 Product Description Manual page 46

Functional
Description
Disk Format
Sector Format
Addressing Structure
3-6 Product Features
This section provides a functional description of the
HP C2233/34/35 disk drives.
The head/disk assembly (HDA) contains three, four, or five
disks (see figure 3-1). The bottom surface of the bottom
disk is reserved for servo code. The remaining surfaces are
available for user data.
Each data surface contains 1522 data tracks. Nine tracks
are reserved for use as spares and two tracks are used for
maintenance. This leaves a total of 1511 tracks available
for user data. Figure 3-2 displays the physical allocation of
the tracks on the media. The tracks are divided into 48, 60,
and 72 user sectors in the inner, middle, and outer zones,
respectively. In addition, there is one spare sector on each
track. Each physical sector can store 512 bytes of user data
in the standard format. The user can choose to format the
drives using other sector sizes (from 180-992 bytes).
The smallest directly addressable storage area on a data
surface is a sector. Accessing a sector is accomplished when
the controller specifies the address of the cylinder, head,
and sector. The formatted sector bytes are allocated as
shown in figure 3-3.
All addressing between the disk drive and the host is
logical. The drive's embedded controller converts the logical
block address into the appropriate physical address (Le.
C"jlinder, head, sector), allowing for any sparing operations
that have been performed. To support multiple 512-byte
block sizes, the drive automatically blocks and deblocks the
physical sectors into the currently specified logical block
size.
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