Used in a professional environment, five SCSI hard drives are considered the perfect configuration for entry-level servers.

In professional environments RAID 5 is what is most frequently used these days. Here there are already several aspects that speak against the use of IDE systems. For one thing, the hard drives are still slower than conventional SCSI models. Another point is that no IDE drives exist to date that are designed for continuous operation, although Maxtor will be remedying this situation in the near future with a new product line.

Furthermore, the IDE standard only permits two drives per channel, which, in practice, limits the total number of useable drives to a dozen at the most. Dual-channel SCSI controllers can, by contrast, serve up to 15 drives per bus.

Even in terms of handling, there are shortcomings with IDE: while so-called Hot Plugging (the exchange of a drive without restarting the system) has for years been common practice with SCSI, this is only possible with a few IDE controllers. In addition, the necessary mobile rack systems are still rather scarce.

Last but not least, a further weak point in the IDE segment is the implementation of RAID 5 solutions within acceptable price ranges. If you do not wish to use the system processor to capacity, you will have to use an RISC chip. The more storage space (cache) available, the better this chip will work.

In summary: SCSI is quick, reliable, flexible and compatible. And SCSI is expensive - this factor is, however, quite acceptable in the server segment, provided that the system works quickly and reliably.