Hitachi's naming conventions for hard drives were adopted from IBM, which is why the desktop drives are called DeskStar, the enterprise models go as UltraStar and all 2.5" hard drives for mobile applications are named TravelStar. 7K100 represents the current generation that works at 7,200 RPM and offers capacities of up to 100 GB. There is also a version called the E7K100, which is especially designed for non-stop operation.
A total of six different 7K100 versions are available; there are three capacities (60, 80 and 100 GB) and each can come with either the UltraATA/100 or Serial ATA 150 interface. All of these use two storage platters; only the 100 GB version makes full use of the available space. This results in 50 GB per platter or 81 Gbits per square inch. The drives feature 8 MB of buffer memory and are RoHS compliant. In case you haven't heard of this one, RoHS stands for "restriction of use of hazardous substances", and is a mandatory directive for electronic devices and components in Europe. It forces manufacturers to use environmentally acceptable materials and to take products back for recycling.
With raw transfer rates of up to 54 MB/s, the TravelStar 7K100 is the fastest 2.5" hard drive we've seen yet. When taking a look at the average data transfer speed it is still able to maintain 40 MB/s. (We found it a bit surprising to see that Seagate's new drive isn't able to keep up with these numbers at all.) At 15.1 ms, its access time also is rather quick in comparison to other 2.5" drives.