SCSI, IDE or Serial ATA for your next hard disk?

If you have been playing around with PCs for long enough, you will know how confusing are the interface standards for connecting your hard disks to your system. ISA, EIDE, IDE, SCSI, UltraSCSI, SCSI-2, Parallel ATA (PATA), UltraATA and, of late, the Serial ATA (SATA) already exist. In the meantime, several other standards have cropped up and added to the confusion. These include Serial ATA II (SATA II), Dual SATA and Serial Attached SCSI.

Forget all of these abbreviations if you are thinking of replacing a dead hard disk or simply increasing your storage capacity. These abbreviations are meant to confuse us. Are you aware that IDE is just the same as Parallel ATA?

Let's see. The most common standards on the market today are still the IDE, SCSI and Serial ATA. While most motherboards still come with an integrated IDE hard disk controller, more and more of the new releases already come with a support for Serial ATA. Some people believe that this standard will be the mainstream of hard disk interface in the near future.

Serial ATA has a number of advantages when compared with the IDE that you may still have in your one-year-old PCs. First, the IDE standard uses inflexible ribbon cable, in which the signal traveling along one strand may interfere with the signal in the next. The bandwidth is limited. On the other hand, a Serial ATA hard disk uses a different kind of cable. While the IDE ribbon cable has 31 strands, the Serial ATA has only seven wires -- four of which are the signal lines.

The more flexible Serial ATA cable can also be up to one meter long, as opposed to 40 cm with the IDE ribbon cable. It means that, unlike the IDE, you will have more freedom in the positioning of your hard disks. Another plus is that you do not have to worry about setting the devices as master or slave, as you have to do when installing two IDE devices on one IDE channel.

Unfortunately, the Serial ATA hard disks are not coming into the market as fast as the controllers and the motherboards that support this new standard. However, if you look hard enough, you will find them. Fujitsu, one of the leading hard disk makers in the world, recently introduced a 2.5-inch Serial ATA hard disk for notebooks and other portable devices.

What about the SCSI standard and all its variants? The SCSI is expected to remain the interface of choice for servers -- especially those on which mission-critical applications are run. SCSI hard disks offer a more complete range of important features, including self-monitoring and reporting. They tend to have longer Mean Time Between Failure (MTBF), which indicates a longer life expectancy. However, the SCSI hard disks are noisy and they generate far more heat. These two are the main characteristics that make them rather unsuitable for desktops.

So, if you are replacing your hard disk, think Serial ATA. If your motherboard does not have a Serial ATA controller already built in, you can buy a Serial ATA adapter. If your new motherboard already has this controller but you do not have the budget to replace your IDE hard disk, don't worry.

There is also a Serial ATA to IDE adapter that will connect your Serial ATA controller to your IDE hard disk. But, then again, you will still have to spend money. So, why not just replace your hard disk with a new one? One last comment: Make sure that the new hard disk has 8MB of cache buffer memory. -- Zatni Arbi