Flash memory-based solid-state disks are on course to quickly replace hard-disk drives in laptop computers, if the evidence of this year's Computex tradeshow is to be trusted.

Laptops with solid-state disks are plentiful at Computex in Taiwan, an event where the world's most important PC manufacturers and component makers meet buyers from around the world, that makes a good gauge of the direction of the industry.

Solid-state disks are lighter and quieter than hard drives. Flash-memory disks use less power and are sturdier than hard drives. They are in use in Toshiba's Dynabook SS RX1 and Palm's Foleo.

The transition to solid-state disks is being accelerated by fast price drops in the flash market. An 8 Gbyte chip that cost around £6 at the end of 2006 currently costs about £4 on the spot market. That's a big drop in six months.

SanDisk launched its first SSD (solid-state disk), a 32 Gbyte model, at January's CES tradeshow. A mere six months later at Computex SanDisk is showing a 64 Gbyte model. The company says much higher-capacity drives are possible today but will be too expensive, so it's increasing the capacity of its drives while keeping them at what it considers the sweet-spot of price and storage space.

Like SSDs from competitors, the SanDisk drives are offered as drop-in replacements for 1.8in and 2.5in hard-disk drives and so can be offered by system makers without the need for any modifications. As SSDs become more common the company believes smaller form-factor drives will be used in machines specifically produced for solid-state storage.

"The old technology of the hard disk is going to go away from the mobile PC market and be replaced by [solid state] media," said Doreet Oren, director of product marketing at SanDisk's computing solutions division in Israel.

Some analysts agree. In a report issued in May, iSuppli said it expects 24 million laptops sold in the fourth quarter of 2009 - about 60 percent of the anticipated market - will have flash storage, versus less than 1 percent in the last quarter of 2006.

Also on show at Computex is a wide range of solid-state disks intended for the industrial sector. Such drives are targeted at military and aviation applications and began replacing other storage methods several years before their entry into the PC market, thanks to the willingness of such customers to pay higher prices.

Apacer Technology is demonstrating a 128 Gbyte industrial SSD that can replace a 2.5in hard drive and operate at temperatures between -40º and 85º Celsius. It will be available in the fourth quarter of this year, and a second version with double the data read speed of 200 Mbit/s will be available in early 2008.

Alongside it was a flash-based Raid (redundant array of independent, or inexpensive, disks) drive which has two Compact Flash card slots. The capacity depends on the cards used.

It's not only in the SSD arena that storage advances are on show at Computex.

Toshiba has the latest in its line of 1.8in hard-disk drives, a model that can store 100 Gbyte, on show. The drive can be fitted into portable media devices, such as the iPod or ultra portable PCs. Toshiba is also using Computex to unveil its first HD DVD rewriter drive for laptop computers. A single-layer HD DVD-RW disc can store up to 20 Gbyte of information, which is just over four times the capacity of an equivalent DVD.

Hitachi Global Storage Technologies has its 1 Tbyte drive that was unveiled at CES and new at the show is a 250 Gbyte 2.5in drive for laptop computers. The 5K250 includes drive-level encryption and has 56 percent more storage space than its predecessor, the 160GB 5K160.