The ProLiant Storage System UE is perfect for companies that store business-critical data and applications and require fast throughput, high availability, excellent serviceability, and large storage capacity. The UE rackmount model supports up to eight 1.6-inch high or 12 1-inch high hot-pluggable Ultra Wide SCSI-3, Fast Wide SCSI-2, or Fast SCSI-2 hard drives on a single SCSI bus. If you are using Compaq's 18.2GB hard drives, that adds up to over 145.6GB of storage capacity - and all this capacity requires just 4U of space in your rack. Plus, the ProLiant UE supports the Ultra Wide SCSI-3 interface, enabling it to transfer data at up to 40MB per second. That's double the data transfer rates of Fast Wide SCSI-2.The ProLiant automatically sets the SCSI ID when a drive is inserted into a drive bay. The drives, power supplies, and fans are all hot-pluggable. Its cooling fans are redundant and the power supply can also be made redundant through Compaq's upgrade option. Another option available for the ProLiant is the Compaq SMART-2 Array or the Compaq Smart Array 3200 controllers, which enable the ProLiant to support RAID fault tolerance (RAID levels 0, 1, 4, and 5). When coupled with one of these controllers and Compaq's Insight Manager (4.20 or higher), the ProLiant can also provide serveral drive fault-prevention features. These features include prediction of drive failures and pre-failure replacement, notification of a drive failure, and monitoring of internal temperature and fan status. The front panel of the ProLiant has LEDs that provide a quick visual assessment of the overall system storage status, including drive activity, when a drive requires service, and when power is on or off.