Not all interfaces support the same devices. Depending on what devices and models you
are trying to use, one interface may make much more sense than another. Fortunately, the
market has evolved so that there are really only two main interfaces used today for hard
disks: IDE/ATA and its variants, and SCSI and its variants. The fact that there are only
two standards in common use means that each of them supports a large number and variety of
devices. In addition, this makes it easier for software support to be made universal, and
this is no longer much of an issue when using these mainstream interfaces.
IDE/ATA tends in general to support a larger number of hard disk models, and also
optical drives and other devices, especially economy models. This is not due to any
particular technical advantages that IDE/ATA possesses over SCSI. It's simply a function
of IDE/ATA being more popular than SCSI, and therefore offering manufacturers more of a
target market than SCSI does. SCSI tends to have better support for high-end devices and
also more device types.
All of this means that the casual home user is more likely to be interested in IDE/ATA,
while SCSI is usually the choice for businesses and performance hounds. See
this comparison of the two interfaces for more. In addition, some of the specialty interfaces fill a particular "niche" by offering
connection options and device types not found in the "big two" interfaces. For
example, using USB or a PC Card adapter, you can easily connect an external hard disk to
your notebook PC.
Next: Multiple Devices and Expandability
