SSDs have greater reliability and durability than hard disk drives (HDDs), because they have no moving parts. Data transfer rates can be faster, and booting a large operating system such as Windows Vista can be quick work for SSDs. In addition, they consume less power compared to HDDs, and they are quieter and lighter.

But HDDs are still much larger in capacity, and their cost-per-gigabyte is a fraction of what it is for SSDs.

SanDisk, Others Push Flash

SanDisk, a major player in the world of flash technology, introduced at Computex this week a 64-GB SSD, which the company is targeting toward enterprise users and early adopters, such as gamers. In 1.8-inch UATA and 2.5-inch SATA formats, the new SSDs are designed as drop-in replacements for hard drives in most notebook computers.

According to reports, SanDisk officials have said that it can produce even higher-capacity SSDs, but the expense in manufacturing them would price them out of the market. So SanDisk instead is concentrating on the "sweet spot." The price of the new 64-GB SSD has not been announced.

Apacer Technology, another example of a company banking on SSDs, presented at Computex a 128-GB industrial-grade SSD in a 2.5-inch form factor, able to function at temperatures between -40 and 85 degrees Celsius. It will be available by the end of this year.

Toshiba's Dynabook RSS RX1, an ultralight laptop, uses a 64-GB SSD instead of a traditional drive, but users can replace it with a hard disk if they wish.

A SanDisk executive yesterday told Reuters that it is "well-positioned" to enter the laptop market, and it has recently signed a deal with Dell to supply 32-GB SSDs for its notebook computers.

Predictions Like Khrushchev

Journalists have been predicting for years that hard drives will be replaced by other technologies, noted Gartner analyst John Monroe. He said that it reminds him of Nikita Khrushchev, the Soviet leader, banging his shoe on the table and saying that his system would bury ours. "In terms of SSDs taking over the world, it's a nonstory."

Industry research firm iSuppli said in a recent report that 60 percent of laptops sold in the final quarter of 2009 will have SSDs, compared to less than one percent in the first quarter of this year. Monroe said that the report was inaccurate in its projections.

First, he said, the performance and power advantages of SSDs have been overstated. NAND flash, he said, actually is slower in many write functions, and the power saving is only about 5 percent of the total power cost of running a laptop. "A laptops's power consumption for storage is only a small part of its total power needs," he pointed out.

He called attention to the huge price differences between HDDs and SSDs. SanDisk's 32-GB SSD will add about $450 to the cost of a laptop, while one can buy an 80-GB HDD for about $50.

He also pointed out that, even at 64 GB, about half of an SSD would be needed just for Windows Vista. "Some form of solid state storage technology will eventually replace HDDs," he predicted. "But it's not going to be NAND flash. And it probably won't be feasibly, cost-effectively manufacturable for at least another 10 years."