The interface that the hard disk uses to connect to the rest of the PC is in some ways
as important as the characteristics of the hard disk itself. The interface is the
communication channel over which all the data flows that is read from or written to the
hard disk. The interface can be a major limiting factor
in system performance. The choice of interface also has an essential impact on system
configuration, compatibility, upgradability and other factors.
Over time, several different standards have evolved to control how hard disks are
connected to the other major system components used in the PC. These have tended to build
upon one another, and often use confusing and overlapping terminology. The result has been
a great deal of confusion surrounding the entire subject. Each time a new variant or
enhancement of an interface is introduced, the interface becomes just a bit more
confusing, particularly for those trying to use older hardware, or to mix newer and older
devices.
To help you understand what can be a baffling subject, this section of the site takes a
comprehensive look at the different interfaces used to connect hard disks to the PC. I
begin by discussing two obsolete interfaces no longer used, and also provide brief
coverage of some "alternative" interfaces that are not commonly employed by
typical PC users, but are important for special applications. Most of the focus is on the
two interfaces most often used on the hard disk. I discuss in detail IDE/ATA and its
enhancements, with a focus on clarifying the confusion that surrounds the use of this most
popular PC interface. I then cover SCSI, the more advanced and flexible interface that
dominates the business workstation and server world, and is becoming the choice of a
growing number of performance-oriented desktop PC users.
Note: This part of the site
is in the discussion of hard disks, and so they will be my primary focus. However, many
other devices use the same interfaces that hard disks do; where appropriate, distinctions
between how hard disks and other devices use the interfaces will be specified. Otherwise,
you can assume that using the interface for optical drives and similar storage devices
will be similar to how hard disks use the interface.
Next: Hard Disk
General Interface Factors
