Although most 2.5" hard drives measure 9.5 mm thick, ultraportables are increasingly using slimmer 7-mm models. Hitachi says it's shipped 25 million of the slender drives already. Now, there's a new one ready just in time for Ivy Bridge ultrabooks. Behold the Travelstar Z7K500:
Well, the inside of it, anyway. That's the interesting part, because the Travelstar offers 500GB of storage capacity squeezed onto a single platter. The platter rotates at 7,200 RPM, and it's backed by a 32MB DRAM cache and a 6Gbps Serial ATA interface. Bursting in and out of the cache is the only way the drive is going to exploit the faster SATA link, though. The media transfer rate tops out at 171 MB/s, which is still pretty quick for a 2.5" mechanical drive. You can thank the platter's 630 GB/in² areal density for the speedy sequential transfer rate.
Hitachi isn't oblivious to the appeal of SSDs, noting that the Travelstar is an ideal companion for a solid-state cache. Notebooks rarely have dual hard drive bays, but the mSATA specification allows even compact ultrabooks to cram a tiny SSD next to a 7-mm hard drive. As notebook makers bring thinner systems to lower price points, I expect we'll see more dual-drive configurations. Acer's Aspire S3, one of the cheapest ultrabooks on the market, already combines a 20GB SSD with a 320GB mechanical drive.
In addition to the 500GB flagship, the Travelstar Z7K500 will be available in 320 and 250GB variants. There are versions with full-disk encryption, as well, and even a couple of "enhanced availability" models primed for blade servers. Hitachi says it started shipping qualification samples last month. Volume shipments are scheduled to begin in March, giving the firm plenty of time to supply notebook vendors piecing together not only Ivy Bridge ultrabooks, but also similarly skinny ultraportables based on AMD's upcoming 17W Trinity APU.