Samsung Electronics plans to launch a 256GB flash memory-based solid-state disk later this year.

The drive, which was unveiled in prototype form at a Samsung event in Taipei, has the same form factor as a 9.5-millimetre high 2.5-inch hard-disk drive for which it is designed to be a drop-in replacement.

Solid-state disks (SSDs) are an emerging type of storage device that use flash memory chips in place of the spinning magnetic disks used in hard-disk drives. The memory chips mean the drives are more sturdy and typically have a higher performance but the per-byte storage cost is also much higher, so they are generally more expensive. That has largely restricted them to niche applications but as flash prices come down they are expected to become more widely used.

Samsung, which is one of the world's largest makers of flash memory chips, is eager to see the drives become popular as their widespread use will represent a big new market for its chips.

The prototype drive announced by the company has a read speed of 200MB/s and a sequential write speed of 160MB/s, said Samsung.

Samples of the drive will be available to customers from September with mass production due by the end of the year.

A version with a similar form factor to a 1.8-inch drive is also expected to be available in the fourth quarter of the year, the company said.

The drive isn't the first SSD launched at this capacity. Last month a competitor, US-based Super Talent began sales of a 256GB SSD but that drive is thicker than Samsung's at 12.5 millimetres. It has a SATA I interface, which means read speeds of 65MB/s and write speeds of 50MB/s.