Course 2: SCSI School
SCSI vs. IDE
Over the past 15 years, the two most prevalent interface standards have been
IDE/ATA and SCSI. This in turn has generated an ongoing debate in IT circles
as to which interface is superior. The fact that the two technologies co-existed
without either becoming obsolete, is an indication that each interface offers
advantages over the other, as determined by individual application requirements.
Performance
In many cases, as you will see in the sections that follow, SCSI offers distinct
advantages over its IDE counterpart. For example, in systems comprised of several
hard drives, SCSI is the preferred interface, due to the speed and flexibility it
offers in contrast to IDE (Please refer to
SCSI Specifications)
. SCSI also supports
a wider variety of devices, and offers better multitasking and expandability,
when compared directly to IDE.
Cost
Not entirely common to the “average” end-user computer, SCSI is not normally seen
in systems used primarily for light office applications, games Internet browsing,
etc. Originally, this was due to cost-driven demand; with the less stringent
performance requirements of typical end user systems, the benefits of SCSI would
not be as noticeable as they would be in more industrial/professional-based
configurations, therefore negating the distinct performance advantages offered
by the SCSI interface.
In turn, because the performance enhancements were not as essential to end users
as they were/are in business/industrial IT settings, consumer needs trended
towards IDE, while professional settings were more geared towards SCSI. In this
regard, SCSI has been considered by some as a specialty technology – like any
other IT standard, the price of “mainstream” technology declined (in this case,
due to a boom in the home computer market), while the cost of SCSI equipment
remained relatively static.
Conclusion?
Although SCSI offers distinct advantages over IDE in terms of performance,
the decision to include the SCSI interface in system architecture often requires
a theoretical balance between cost and performance. While the extended capabilities
of SCSI, for instance, would be of benefit in most systems, the difference in price
is often the deciding factor. In most cases, if the demand for high performance
peripherals were high enough, SCSI would be the obvious choice.
As I/O technology has evolved, new interfaces (i.e. SATA /150, SATA /300) have
become the industry standard. Far from an obsolete or “dead” technology, SCSI is
not uncommon in industrial applications requiring legacy performance. In fact,
there have been several modern extensions of SCSI technology, such as iSCSI and
SAS (Serial-attached-SCSI), which rely on the speed and power offered by SCSI architecture
Next – Chapter 3 - What is an SCA/RAID connector?
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