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StarTech University offers computer enthusiasts and IT professionals a chance to learn more about new technologies and innovations in the IT world. Take some time to review the material, then pass the exam to earn your printable certificate for each course.

Course 2: SCSI School

Chapter 2: 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.


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.


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.


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?