E is for Enterprise; several manufacturers add features to their standard desktop drives to make them perform better in tightly packed clusters and in high performance RAID arrays. Hitachi was first to market with a 1TB drive nearly two years ago. The first 1TB drive required five platters to achieve the milestone mark; because of this, the drives ran a little on the...touch it with your finger and feel the pain, hot side. Areal densities have increased over the two year life span of 1TB drives and now Hitachi is able to deliver a 1TB drive in only three platters.
The new E7K1000 is more than just a refresh on their desktop product. The new drive features 32MB of cache, up from 16MB. The additional cache should help to decrease latency access times. The feature most useful for the E7K1000's target audience is the Rotational Vibration Safeguard (RVS). RVS is a set of sensors located on the drive and when vibration is detected the internal software adjusts the head's position in relation to the platters to compensate.
Enterprise class drives are intended to be used in RAID and nearline storage servers; a good example where home and SOHO users can benefit from enterprise technology is NAS servers.