Hybrid and solid-state drives coming your way

The Jakarta Post ,  Jakarta   |  Mon, 09/24/2007 3:17 PM  |  Life

Arnawa Widagda, Contributor, Jakarta

Though many may not realize it, great strides have been made in storage technologies in the past few years. Storage capacity has increased tremendously, thanks to advances such as perpendicular technology, which allow manufacturers to stuff even more data into the same space.

Hitachi, Seagate and Western Digital have announced drives with a capacity of 1 TBytes or 1000 GBytes. That is enough space to hold about 250 feature films of DVD quality. We are also seeing features that used to be in the domain of enterprise users trickle down to ordinary desktops and notebooks. Serial ATA II brought native command queuing, up to 300 MB/s transfer rates and hot plug support to many desktop PCs.

Despite all this, hard drives, or more importantly their performance, really have not changed all that much. In general, the read and write speeds of hard drives fall somewhere between 60 to 80 MB/sfar from the theoretical bandwidth of even Serial ATA I bandwidth of 150 MB/s or even plain Ultra ATA's 100 MB/s. Simply put, you would have to be accessing four hard drives simultaneously to even come close to Serial ATA II's bandwidth.

This year, we are seeing new technologies promising to break through this performance barrier The one with the most potential is quite probably solid-state drives or SSDs. Unlike traditional hard drives, these drives uses flash memory chips, not unlike those used in MP3 players such as Apple's Ipod Nano, thumb drives, various removable media such as CompactFlash, SecureDigital and the like. Because of their nature, SSDs are very fast. Data can be accessed much more quickly, transfer rates are higher or about the same (depending on the drive). Transfer rates are the same regardless of where data is stored, unlike traditional hard drives. Since they lack any moving mechanism, they are also less likely to get damaged from shock and vibration, plus they are also much more quiet and energy efficient.

Two major drawbacks with solid-state drives are capacity and cost. The largest solid-state drives available today are limited to 64 GB and come with a hefty price tag. Take, for example, the much applauded MTRON (http://www.mtron.net/eng/index.asp) solid-state drives. They have 2.5 inch SSDs ranging from 4GB to 32GB and up to 128GB for 3.5 inch versions. MTRON boasts these drives are capable of transfer rates as high as 100 MB/s and a latency of 0.1 ms. For comparison, the fastest desktop drive available today, the 10.000 rpm Western Digital Raptor, ""only"" offers transfer rates of 75 MB/s and a latency of 8.5 ms. The MSD-SATA6025-032, which is a 2.5 inch 32GB drive, originally sold for approximately US$1499 in the U.S., but now can be found for just under US$1000.

For those who want a more affordable alternative, hybrid drives will likely be it. These drives still rely on traditional magnetic disks to store data, but add NAND flash memory chips as ""buffers"". Originally, they were conceived to improve power consumption and responsiveness. When an equipped PC or notebook is awakened from sleep or hibernation, it will access data from the much faster NAND flash memory instead of waiting for the drive to ""rev up"" and get the data. Not surprisingly, hybrid drives are targeted at laptop and notebook users.

Your typical hybrid drives usually comes with 256 or 512 MB of NAND flash memory. Now, there is a new twist to this. M-Cell Hyper-Drive from Japanese based DTS (http://www.dts-1.com/e/index.html) is a 3.5 inch enclosure containing a 2.5-inch, 5400rpm, 120GB SATA drive, with 1GB of write-through DDR2 DRAM. This RAM cache will allow the drive to have a similar performance to ""pure"" solid state disks, provided the data being read or written is inside the cache. The use of RAM to speed up transfer rates is not new, in fact these features can be found on many traditional SCSI storage solutions. The use of RAM has its drawbacks though -- although it is much faster than NAND flash memory, the data stored inside will be lost when the device is turned off. The drive does have protective measures to make sure data loss will not happen in such cases. M-Cell drives are available in 80GB, 120GB and 160GB capacities, with the 80GB costing about US$136.

The other alternatives that you will most likely be using in the near future are Intel's TurboMemory and AMD's HypeFlash. In principle, these features works in a similar way to NAND flash memory in hybrid drives, but instead the flash memory is incorporated into the motherboard, not the drive. Notebooks based on Intel's Santa Rosa platform are the first on the market with such technology.

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