Hard drives have long utilized small bits of cache memory to boost performance, and some recent hybrid hard drives already combine up to 256MB of NAND flash memory with traditional platter-based storage. Now a Japanese company called DTS has taken the idea of hybrid drives in a slightly different direction, having just unleashed a new type of hard drive called Mcell that offers 1GB of on-drive cache using standard DDR RAM. DTS markets the disc as being a significantly cheaper way to get some of the benefits of solid state drives without the price.
The Mcell is an interesting beast. In terms of size, it fits in the standard 3.5" form factor, but inside it actually contains a 2.5" 5400rpm hard drive, a stick of 1GB DDR2 RAM, and a special chip from DTS that contains a real-time OS and CPU. Don't let the slow RPM fool you. The combination of the write-through cache and the 2.5" disc should afford much quicker access times than with 3.5" 7200rpm drives.
According to DTS, the additional memory combined with its I/O management chip drastically improves hard drive transfer speeds: the drive sees speeds above 110MBps in random read tests for data sizes of 64KB to 512MB. Larger data samples than that, of course, will tend to go outside the cache and performance will drop off. And we need remind you that these are manufacturers claims, so take them with a grain of salt.
If trustworthy, 110MBps is an impressive figure considering that many 7200rpm SATA hard drives have sustained transfer rates on the order of 60MBps, and the SATA interface itself tops out at 150MBps. Again, this data makes sense to us because of the benefits of the smaller 2.5" drive and the random read/writes of small bits of data.
The Mcell hard drive. Photo courtesy DTS
The drive will initially be available in 80GB, 120GB, and 160GB sizes, with the 80GB model selling for ¥15,800 ($136.15). According to the drive's product page, it contains a "quick boot up option" as well as a "one-stop software failure option," although it's not entirely clear how the latter will work.
Hybrid hard drives are seeing increased interest among systems builders, professional and enthusiast, with operating system features such as Windows Vista's ReadyBoost promising to increase overall system performance. As RAM gets faster and cheaper, Flash-based drives become more attractive to system builders looking for fast performance and low power consumption. Hybrid hard drives are also likely to become more popular as they combine the fast transfer rates of Flash-based devices with the larger storage capacity of traditional magnetic drives. While the Mcell isn't a "true" hybrid drive—those have nonvolatile Flash RAM on board—it is a stepping stone on the way to the next generation of hybrid storage.
Additional images can be found at Akiba, where the availability of the standalone drives was first reported. Mcell is currently available in Japan, but we're trying to find out when and if these drives will be coming to North America. DTS has been selling technology under the Mcell name for a couple of years but has previously focused on the RAID market.
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