Despite their appeal, Solid State Drives (SSD) wonit make real sense for laptops for several more years, according to Computerworld. The curent technology is still too expensive, slower on I/O and has a more limited lifespan.

Right now, consumer grade SLC SSDs use a different structure that has good capacity and price, but suffer compared to corporate grade MLC SSDs by having slower I/O and 10 times fewer read/writes over their life span.

"I think you need to get to 128 GB for around US$200, and thatis going to happen around 2010," said Joseph Unsworth, an analyst with Gartner Inc. "Also, the industry needs to effectively communicate why consumers or enterprise users should pay more for less storage."

In 2008, an SSD will cost at least US$2.00 per gigabyte. For hard disks, the cost is about $0.38 per gigabyte. Two years ago, SSDs were $17.50 per gigabyte.

Intel and MicronTechnology are working to be the first to break the $1.00/gigabyte level.

One problem still be addressed, however, is that NAND SSDs are very good at sequential reads, and so they excel in handhelds, for example, where there is typically audio or video playback. On the other hand, theyeire not so good right now at random writes. To adjust for that, manufacturers have to add special controller electronics, buffers, multiple controller channels, and interleaving.

The CW article proceeds to go into terrific technical depth of the design issues of current SSDs and does some performance testing against traditional hard disks. One of the keys is understanding the difference between SLC amd MLC SSDs.

The upshot is that while SSDs will eventually replace hard disks, especially in laptops, and the technology is the fastest growing technology in the history of the semiconductor market, the best market right now is for high end servers and heldhelds where reading data is the primary use.

Referring to Appleis MacBook Air, Avi Cohen with Avian Securities LLC in Boston said that SSDs will do well today in ultra portables not because of any performance advantage, but because "Itis cool."

However, by 2010, all that will change, and the SSD will likely become the storage of choice, based on performance and cost, for all laptops, according to Gartner.