Two and a half years after Apple launched its iPod and began to steal thunder from Sony, which had ruled the portable music market since the Walkman appeared in the 1980s, the company unveiled the first hard-disk drive based music player to bear its name on Monday.

The Vaio Pocket VGF-AP1 has a 20GB hard disk drive and a 2.2-inch colour LCD screen with 320-x-256 pixel resolution. In addition to acting as the main user interface, the screen displays track information when songs are being played and displays, if available, album art.

On the right-hand side of the display is a touch-sensitive panel dubbed "G-sense" that is used to control the player. Users can navigate a series of on-screen menus by running their fingers over the panel in the appropriate direction.

The player is compatible with Sony's ATRAC3 and ATRAC3 plus digital music formats, both of which include digital rights management (DRM).

By using Sony's Sonic Stage or Music Move software, both of which are bundled with the player, tracks in MP3, Windows Media Audio or WAV audio file formats can be converted into ATRAC and uploaded to the player. The software is compatible with Windows 98SE, 2000, ME, XP Home and XP Professional operating systems.

Fans of Apple's iPod will be pleased to know the Vaio Pocket is both larger and heavier than the comparable 20GB iPod model.

The Vaio Pocket measures 115-x-63-x-17mm, compared to the iPod's 104-x-61-x-16mm. The Vaio Pocket weighs in at 195g, which is heavier than the iPod at 158g, according to information from Sony and Apple.

In the area of battery life the Vaio Pocket easily beats the iPod, offering around 20 hours of playback compared to the iPod's 8 hours.

The Vaio Pocket will go on sale in Japan on June 5 for around ¥53,000 (around £260). There are no plans to sell it outside Japan at this point.

The player is the first Sony will sell under its own brand name, although it began selling a product under its Aiwa brand name earlier this year. The Giga Pavit player is based on a 2GB hard disk drive from Cornice and is on sale now in Japan for ¥35,000 (£165).