Construction and Operation of the Hard
Disk
To many people, a hard disk is a "black box" of sorts--it is thought of as
just a small device that "somehow" stores data. There is nothing wrong with this
approach of course, as long as all you care about is that it stores data. If you
use your hard disk as more than just a place to "keep stuff", then you want to
know more about your hard disk. It is hard to really understand the factors that
affect performance, reliability and interfacing without knowing how the drive
works internally. Fortunately, most hard disks are basically the same on the
inside. While the technology evolves, many of the basics are unchanged from the
first PC hard disks in the early 1980s.
In this section we dive into the guts of the hard disk and discover what
makes it tick. We look at the various key components, discuss how the hard disk
is put together, and explore the various important technologies and how they
work together to let you read and write data to the hard disk. My goal is to go
beyond the basics, and help you really understand the design decisions and
tradeoffs made by hard disk engineers, and the ways that new technologies are
being employed to increase capacity and improve performance. |
Photograph of a modern SCSI hard disk, with major
components annotated. The logic board is underneath the unit and not
visible from this angle. |
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