Sun is working on a fourth generation of its 9840 fast-access tape format that will offer 75GB native capacity, nearly double the current 9840C's 40GB.

The native transfer rate will also probably double the 30Mbit/s of the 9840C to 60Mbit/s, the company said.

It only takes 12 seconds to access a file on the 9840 because of its twin-spool, mid-tape parking design. That means searches for files start from the middle of the tape.

The tape also rides on a cushion of air that eliminates a lot of the friction between the tape and guides, increasing speed and prolonging life. This has made it popular in large IT shops.

Dave Woodruff, Visa's director of media operations, said: "We rely on (it) as the real workhorse of our data centre."

The new drive will be backwards-compatible with all 9840 media and will be able to encrypt data it writes to tape. Sun will develop the drive while Imation develops the half-inch media. The 9840D is expected to be available next year along with pricing information.