A final consideration when evaluating different interfaces is the cost of the
interface. In fact, I should really says costs, because there are several
different aspects involved in assessing the monetary costs associated with an interface.
While this is a non-technical consideration, cost considerations are actually probably the
most often used by those making an interface choice, not technical ones.
The most important cost consideration is the hardware and software cost for
implementing the interface. What this often boils down to is whether or not support for
the interface is already included in a given system. For example, the presence of IDE/ATA
controllers on all modern motherboards makes this interface less expensive for most people
than going with SCSI, which would require the addition of a SCSI
host adapter. Similarly, USB has been around for years, but is only becoming popular
now that almost all new systems have built-in support for it, both hardware and software.
Some interfaces also require more expensive support hardware than others--such as
specialized cabling, termination, external enclosures and so on.
Another cost consideration is the cost of the actual devices that are used on the
interface, as not all are equal. Generally speaking, this matter is related to the cost of
the interface hardware as well--interfaces that are more expensive to implement generally
have more expensive hardware sold with them, while inexpensive interfaces have cheaper
storage devices. This results naturally from market forces: few people will want to pay
$200 to implement a particular interface to enable use of a $50 device.
When considering the costs associated with an interface, be sure to look at all
of the costs, including some that may be hidden. For example, the SCSI interface may
require an up-front investment, but once set up offers expandability and other advantages
that may offset its cost. Of course, what is a worthwhile expenditure depends primarily on
the needs of the individual.
Next: Obsolete Hard
Disk Interfaces
