UPGRADING REPAIRING PCs

4
SCSI and IDE Hard
Drives and Optical
Drives
Chapter 4
Understanding Hard Disk
Terminology
When installing IDE hard disks in particular, at least three parameters
must be indicated in the BIOS Setup program to define a hard
disk.
Note
Understanding how hard drives store data is an enormous topic.
If you’d like to learn more, see Chapters 9 and 10 of Upgrading
and Repairing PCs, 12th Edition, also published by Que.
Heads, Sectors per Track, and Cylinders
If this information is not accurately listed in the BIOS configuration,
the full capacity of the drive will not be available unless special
hard disk drivers or supplementary BIOS cards are used.
Whenever possible, the computer’s own ROM BIOS should fully
support the drive’s capacity.
For drives larger than 504MB (binary) or 528 million bytes, additional
translation options are also required with MS-DOS and
Windows to achieve full capacity.
Hard Drive Heads
A hard drive is comprised of one or more platters, normally made
of aluminum but occasionally made of glass. These platters are covered
with a thin rigid film of magnetized material. The magnetic
structures of the platters are read or changed by read/write heads
that move across the surface of the platters but are separated from
it by a thin cushion of air. Virtually all platters are read from both
sides.
Sectors per Track
The magnetic structures stored on the hard disk platters are organized
into sectors of 512 data bytes each, plus additional areas in