Ultra320 SCSI can be seen as the "traditional" SCSI. It is a parallel bus, which connects up to 15 devices via 68-pin flat ribbon cables. The controller itself is one of the SCSI devices, and devices are automatically or manually assigned an ID. Each end of the SCSI bus has to be terminated to avoid signal reflection. Most devices carry a built-in termination feature, which can be enabled by setting a jumper. If you work with external devices you might have to terminate the bus by plugging in an active terminator module. Serial Attached SCSI automatically terminates each connection.

The last SCSI standard, Ultra320 SCSI, offers a maximum bandwidth of 320 MB/s, which are far from typical. Over 250 MB/s are realistic, but you should always remember that the total bandwidth is shared between all devices running on a SCSI bus. For this reason it makes sense to split drives into separate arrays, or into a nested RAID setup for the sake of maximizing performance.

Hitachi UltraStar 10K300, HUS103014FL37800 (147 GB, SCA)

Hitachi still has a 3.5" professional hard drive family, which runs at 10,000 RPM and offers up to 300 GB capacity. The 10K300 is available at 300 GB, 147 GB or 73 GB; we took a look at the 147 GB version. It comes with an SCA interface, which facilitates drive handling.

This drive isn't quite the best performer, but it is available at 300 GB capacity points, and at a much lower cost than Seagate's new Cheetah 15K.5. While the maximum read transfer rates of 87 MB/s are still acceptable, the minimum speed of 45 MB/s is considerably slower than the 51-69 MB/s minimum speeds of 15,000 RPM drives.

If you're looking for high capacity hard drives we recommend having a look at Serial ATA models that have been validated for long term 24/7 operation. They won't provide the same performance as professional SCSI or SAS drives, but they are considerably cheaper and they offer much more storage capacity for the buck. Lastly, the performance drawback can be largely absorbed by creating reasonable RAID arrays.