Time to Move to a Solid State Hard Drive?

Solid State Drives (SSD), initially developed in the 1980s, have to date, due to cost, been largely targeted at military applications and enterprises looking for enhanced performance for large databases and other such demanding applications. However, cost reductions have now brought SSD to the point of beginning to penetrate the general consumer electronics market. Many of us in fact are already using SSD technology in our iPhone or iPod.

An SSD is based on solid state semiconductor technology similar to the familiar Secure Digital (SD) card in a camera. Unlike the magnetic hard disk drive (HDD) with rotating platters and moving arm, an SSD has no moving parts. No power is required to retain data which can persist for up to 10 years.

Reliability

The lack of mechanical components provides SSDs with greater robustness towards shock or vibration, temperature extremes and humidity which has made them popular for defence applications (MIL-STD-810F military standard). Solid state memory can survive drops, resist magnetic fields and survive water damage. I can personally attest that a solid state game memory card will survive the washing machine to work just fine. Ruggedness is part of the reason SSD are found in mobile consumer electronics applications.

Speed

Speed of data access is an often raised advantage of SSD. Typical access times for SSD can be 35 to 105 micro-seconds compared to 5,000 to 10,000 micro-seconds for a conventional HDD. However, recent research by IDC has indicated that the performance gap between 7,200 rpm 2.5 inch drives and systems with SSD is smaller than expected. Performance of the entire system was the main factor to the smaller than expected gap rather than just that of the SSD. IDC have noted that system redesigns will be necessary for PCs to obtain the full benefits of an SSD drive - something to remember.

Heat and Power

Less waste heat generation and lower power requirements are two advantages of SSDs. Less energy use translates into smaller power supplies and smaller energy bills. Reduced heat load requires less cooling and, in some cases, may eliminate the necessity for cooling fans. Lower heat and power requirements are ideal for mobile consumer electronics applications.

A recently developed inductive coupling wireless communication technology promises to significantly reduce SSDs internal wiring requirements and power consumption by some 50 percent.

Lifespan

A conventional computer HDD typically has a lifespan that exceeds 3 years. All evidence points to current SDDs exceeding this. Intel are claiming 5 years "useful life" for their X-18M SSD based on a hefty data writing load of 100GB/day. Metron are willing to offer a 5 year warranty on their SSD Pro 7000 series.

A prominent SSD manufacturer, BiTMICRO recently estimated a 12.9 year life for an SSD in a database application. This lifespan was estimated despite the conservative assumptions of a fairly rigorous workload and no application of life extending strategies such as caching and wear levelling. Wear levelling is achieved by balancing algorithms which monitor the disk block write totals and can greatly extend the operational lifespan of an SSD.

STORAGEsearch.com recently estimated (computationally) that the life of SSD in enterprise server applications was of the order of 50 years.

Cost and Capacity - the Deciding Factors

Cost and capacity are the two areas where conventional HDD can exceed SSD available in the market today. Things are changing quickly though.

Capacity

At present the maximum magnetic HDD capacity available is 2 TB (Western Digital's 2TB WD Caviar Green). Hitachi is aiming to produce 4TB desktop drives using new nanometer recording technologies by 2011.

The highest capacity SSD (far greater cost) is the 1TB Nitro by pureSilicon Inc. PureSilicon have been able to achieve an amazing 15.4GB per cubic centimetre. Mean Time to Failure (MTTF) is some 2 million hours (228 years).

Cost

At the moment, consumers will still pay a fairly hefty premium for a SSD instead of a HDD with the price premium sometimes reaching $1,000. This situation is changing rapidly though with research firm IDC reporting that costs are decreasing at an impressive 40 to 50 percent annually and that price parity may be achieved by 2011.

Present Market for SSD

Despite the advantages of ruggedness, low power consumption and faster speeds combined with reasonably large capacities, price seems to have squashed any significant uptake of SSD, particularly in the consumer computing market. With the current price premiums this is not surprising. Thankfully, 2011 is not far away.

Many major PC manufacturers are already testing the market with SSD equipped computing offerings including;

Dell Latitude D430 Notebook (32GB SanDisk SSD)
Eee PC S101 (up to 64GB)
Toshiba Portege R500 sub-notebook (up to 128GB)
HP EliteBook 6930p enterprise notebook (SSD optional)
Lenovo S10 mini-notebook (16GB SSD optional)