There are a number of design factors and issues that affect the performance--and hence
the performance specifications--of the hard disk. Of
these, I refer to performance considerations that relate only or primarily to the
capabilities of the hard disk drive itself as internal performance factors. In
theory, these are not directly related to the interface or other parts of the system external to the hard disk, which means they should be
reasonably consistent and even "portable" from one system to another. These are
really the basis of hard disk performance, since they dictate the theoretical maximums;
external factors can only further constrain the limits imposed by the design of the hard
disk itself.
This section takes a look at the most important internal performance factors of the
modern hard disk. They are divided into three sections, reflecting the different major
areas of concern regarding internal performance considerations. First, I take a look at
three major design factors related to the mechanics of the drive, which are probably the
most important influence on performance. Then, I'll discuss issues related to how data is
recorded on the platters. Finally, I'll describe some factors that relate to the drive's
integrated controller. For each factor, I will provide a reference to the performance
specifications it most directly impacts.
Note: In order to
avoid duplication, I do not get into describing in detail how the hard disk's various
components work here; I instead refer to the Construction
and Operation section where appropriate.
Next: Mechanical
Design Factors
