US company Sans Digital has come up with a storage design that it claims can deliver many of the benefits of solid-state drives (SSDs) but at less than half the cost.

The concept is an enclosure that looks identical to a 2.5 inch hard drive of the type found in laptops, but containing up to two commodity Compact Flash cards. The drive uses the same SATA interface as a conventional hard drive, while the capacity is limited to 32Gb (2 x 16GB) making the design comparable in storage capability to entry-level SSDs.

At today’s prices, a high-performance Compact Flash card, such as Sandisk’s Extreme III, would cost around £90 ($180) per drive, or £180 ($360) in total. By contrast, in the UK, SSDs of the same size, such as Mtron’s Pro 7000, would normally be around £430 (£860).

The other arguments for Compact Flash cards, compared to conventional hard drives, are lower power consumption, quiet operation, much lower heat output, and the ability to withstand physical shocks. The basic 2-drive unit will be sold as the CompactSTOR CS1T for $45 (£22) a pop, without drives, the same price as the CompactRAID CR2T model, aimed at customers who want to use the concept for basic RAID 1 mirroring.

What Compact Flash can’t quite do is match the performance of an equivalent SSD, at least as far as quoted performance. SanDisk’s Extreme III can manage 30Mbytes/s read and write speeds, some way behind Mtron’s SSD, which has quoted reads of up to 120Mbytes/s read and 90Mbytes/s write.

In real-world conditions, SSDs are faster than a conventional hard drive in terms of reads, but, depending on the precise memory technology used, the advantages are less impressive for random writes.

"The CS1T and CR2T make data backup and protection possible in a restricted environment,” said Sans Digital’s president, Grandy Chen.”The units are designed using standard 2.5” hard drive connectors, making instant upgrades possible by providing mirroring in laptops and IPC computers, where only a single 2.5” hard drive could be installed.”