Engineers at Toshiba have demonstrated a working prototype of a hard disk drive that crams in 50 per cent more data than previous models and opens the way to higher capacity hard disk drives (HDDs). The drive, which was unveiled this week at the company's research and development center in Ome, in one of Tokyo's western suburbs, manages to pack 52Gbits of data into one square inch of magnetic recording space. That's a big jump on the company's current highest capacity commercial drive, a 2.5-inch, 20GB model that has an areal density of 35.1Gbits per square inch (bpsi). In contrast, the areal density achieved with the prototype drive translates into a capacity of 30GB per 2.5 inch platter. The company says it expects the technology won't find its way into commercial products until later this year or sometime next year. Meanwhile researchers are already concentrating on doubling drive capacity to 100Gbpsi before the end of 2003. Toshiba is in a race with other leading hard disk drive makers to increase areal density and so come out with higher capacity hard disk drives. This is especially important for drives with platters - the circular discs coated with a magnetic material on which data is recorded - of 2.5 inches in diameter and below because their smaller size means there is less physical space for data. IBM's latest 2.5-inch drive, the Travelstar 40GN, has an areal density of 34Gbpsi and capacity of 20GB per platter while Fujitsu's MHR series 2.5-inch drives, which were introduced in October, boasted a 36.1G bpsi areal density but still 20G bytes per platter. Toshiba is also pursuing research of even smaller drives. In May 2000 the company put on sale its first 1.8-inch hard disk drive. Initially available with a capacity of 2GB, a 5GB version of the drive went on sale last year and in January this year Toshiba announced 10GB and 20GB versions. The drives weigh just 62 grams and are small enough to be packaged inside a standard type-II PC Card case, making them perfect for use as a bridge media for transferring files between devices or as expansion storage space. In addition to hard drives for computer use, the company also revealed some of its development work underway aimed at drives for new applications. Development of a new type of Audio-Visual hard disk drive (AV-HDD), for use in consumer electronics products, is almost complete and the drive is expected to be on the market before the end of March. Unlike drives for computer use, AV-HDDs impose time limits on the speed with which information can be read off the drive so as to ensure a steady video or audio stream. One of the side-effects of this is increased noise, said Yutaka Arakawa, a specialist in Toshiba's hard disk drive development department. The new drive, a 40GB 2.5 inch model, cuts most of the noise usually associated with AV-HDDs but retains the time limit on read operations to ensure a smooth stream of data, he said. Also under development is a shock-resistant hard disk drive for use on the move. Such applications include a portable video player or when installed in an automobile or other moving vehicle. Conventional hard disk drives can already be used in such applications where audio is required. However, the higher data rate of video requires development of a new drive. Toshiba's model senses imminent shocks and communicates with the drive head to minimize the number of times data reading is interrupted. All of Toshiba's research and development is focused on hard disk drives with platters of 2.5 inches in diameter and below. Such drives are already used in notebook computers and, Toshiba believes, the market for small drives is expected to grow fast as they make their way into audio-visual products and automobiles. In 2004, the company estimates the hard disk drive market for notebook computers will total 39 million, all of which will be 2.5-inch and smaller drives. In automobiles too, a relatively new market at present, that market is expected to total 3 million units, all of which will be in small form-factor drives. In the audio-visual sector, small form-factor drives are expected to make up 6 million of the 22 million unit market in 2004 and in the desktop computer market, a sector dominated by 3.5-inch drives, some 6 million units of the estimated 200 million which will be shipped, said Toshiba.