By Chris Hall

     Year 2007 may well be remembered as the year the IT industry sat up and realized that solid state drives (SSDs) were arriving in capacities that would probably satisfy the needs of most notebook users, at price points within the reach of well-off enthusiasts. Samsung, for example, is now offering a 32GB SSD for around US$350. These are usually flash-memory based drives, and the price of flash has been declining at 50% a year. Experts agree it will continue to do so, and the IT industry can expect SSDs to become more affordable. It seems realistic to expect that within a few years, SSDs will see widespread market take-up, although the exact timeframe is probably impossible to predict. Meanwhile, in April of last year, Dell announced it would be offering a 1.8-inch 32GB solid state drive (SSD) from SanDisk with its Latitude D420 ultra-mobile and D620 ATG semi-rugged notebooks.
     Interesting claims are being made for flash based SSDs. A mechanical hard drive has spinning platters. These take time to “spin up” at power on, resulting in slow boot times. With flash SSDs, boot-up and application launches can see significant increases in speed. Likewise, flash SSDs do not suffer from the mechanical latencies of a traditional hard drive. (The absence of moving parts also makes them much quieter.) Data can be accessed faster and read faster. Can flash SSDs write data faster? This is where the benchmarks seem to indicate a traditional hard drive remains superior, but possibly only on sequential writes. Flash SSDs are also claimed to be more power-efficient and to run cooler than HDDs. This feature of SSDs, together with the possibility of a tiny footprint, makes them a very attractive option for mobile devices. However, this could also be a significant advantage in data centers, where cooling the space around servers can be an expensive proposition.

Key advantage ---- robustness
     A central advantage of flash SSDs is, of course, that they are far more robust than an HDD. This allowed M-Systems (now acquired by SanDisk) to sell flash SSDs for military applications. This factor means that for many users an SSD will be trade-off between cost and reliability. A business executive on the go will feel assured that valuable data is secure as he or she hops between plane and train, although that sense of security currently comes at a significant price premium.

Who offers SSDs?
     A surprisingly large number of companies are now jumping on the SSD bandwagon. During the past year, Eurotrade has spoken face-to-face with Microdia, Super Talent, and Mtron about their SSD products and plans. We’ve also been in contact with Fusion io. We’ve given you their comments in interviews and reports. There are plenty of other companies involved. Flash-memory maker Samsung is one obvious name. Intel, Toshiba, SanDisk, TDK, BitMicro, Micron and PQI can be added to the list, but that’s by no means exhaustive.

At what capacity?
     When a new wave of SSDs, targeting a wide range of applications, arrived over the last year or two, capacities seemed relatively low, and 32GB drives targeting notebook users were assumed to be the sweet spot in the market. Things are changing rapidly, and at CES 2008, BitMICRO has been showing an SSD product series with an upper limit capacity of 832GB, first announced last November. In a 2.5-inch form factor, and utilizing NAND multi-level cell flash memory, these drives are scheduled to ship in the third quarter of this year in capacities ranging between 32~832GB. The interface is SATA II, indicating data transfer speeds of up to 3Gbits/sec. The use of MLC flash, as opposed to single-level cell (SLC), is clearly a technology breakthrough for BiTMICRO, effectively doubling the number of data bits that can be stored in an SLC cell.
     Samsung also unveiled an MLC flash drive, at CES 2008, with a capacity of 128GB, rivaling the storage capability of typical desktop drives.
     This drive is in fact targeting notebooks and is in a 2.5-inch form factor. It is scheduled to ship in the first half of this year. This drive also underlines the power advantage of SSDs; it consumes only 0.5W of power in active mode. Samsung is also planning to make this drive available in a 1.8-inch form factor, at just 5mm thick, targeting ultra-mobile PCs (UMPCs).

So much in so little
     Not to be outdone, Toshiba showed a 128GB SSD, at CES 2008, in a 1.8-inch form factor, with the target market again being notebooks. This drive was one of a series, announced last month, utilizing the higher density of MLC flash. Here the NAND flash resides with the controller chips and DRAM on a platform with dimensions 70.6x53.6x3.0mm (LxWxH). The maximum read speed is 100Mbytes/sec, and the maximum write speed is 40Mbytes/sec. The interface is SATA II. The Toshiba drives are rated for an operating life of 1,000,000 hours.
     The US based Super Talent also released a 256GB SSD recently, in an industry-standard 3.5-inch form factor. This is the largest capacity drive to date in the company’s SATA 35 series. The minimum sequential read rate is 60Mbytes/sec; the minimum sequential write rate is 45Mbytes/sec. Access time is 0.1ms. This SATA SSD drive is geared specifically to military and industrial markets, including avionics and video on demand, factory automation, point-of-sale (POS), ticket vending machines, parking systems and other industrial applications that require high tolerance of environmental conditions. The reliability of this drive is enhanced with Super Talent’s patented wear-leveling algorithms, a technique that ensures that “wear” of the flash cells is distributed evenly.
     Very interestingly, Advanced Media Inc., a subsidiary of RITEK Corporation, showed a SATA 2.5-inch SLC flash SSD at CES 2008, in a RAID configuration. This arrangement managed a whopping read speed of 260MB/sec and a sequential write speed of 130MB/sec.

Intel targets mobile devices
     If Samsung was targeting UMPCs at CES, Intel, last December, announced SSDs in an even smaller form factor, for mobile devices. Intel’s Z-P140 drive was billed by Intel as “smaller than a penny and weighing less than a drop of water.” The actual dimensions are 12x18x1.8mm, in a chipscale package-on-package, and the weight of Z-P140 is 0.6g. At this size, Z-P140 is 400 times smaller than a 1.8-inch form factor drive, and Intel intends Z-P140 to be a component of its Menlow platform for mobile Internet devices, available this first quarter with a capacity of 2GB, scaling to 4GB and 16GB in mid-2008. The read and write speeds of Z-P140 are not necessarily impressive. Reads are rated at 40MB/s and writes at 30MB/s. What does make this an impressive offering for the mobile space is the power consumption, which is rated at a mere 300mW (milliwatts) in active mode and 1.1mW in sleep mode.

SSDs for the enterprise
     One company, Texas Memory Systems (TMS), is targeting the enterprise with its solid state systems. The RAMSAN 500, for example, can provide 1TB or 2TB of flash-memory storage, in a RAID configuration and in combination with 16GB to 64GB of DDR SDRAM cache. The flash is SLC NAND, and the RAMSAN 500 is designed for “high I/O data warehousing, high bandwidth data acquisition, and rich media environments.” Equipped with 4Gbit Fibre Channel or 4x InfiniBand ports, the system is capable of over 100,000 random IOPS or 2GBytes/sec of sustained bandwidth (even with cache misses). TMS point out that, “The RamSan-500 is designed to look like a disk to the network or operating system. Therefore, it is highly interoperable and works in virtually any enterprise environment.”