Matsushita Electric Industrial (Panasonic) plans to begin selling a Blu-ray Disc drive in Japan in June for use in desktop computers.

The drive will be sold as an add-on for existing PCs. It’s expensive and needs a high-end PC. It debuts as the first PCs with built-in drives for Blu-ray or the competing HD-DVD format are being prepared for launch. A single Blu-ray Disc can store as much data as ten DVDs.

The LF-MB121JD is a half-height (41.3-millimetre high) model, which means it will fit into the standard drive bay of most desktop PCs, and has an ATAPI interface. It's compatible with 11 types of writable optical disc, including 25GB and 50GB BD-R (Blu-ray Disc Recordable) and BD-RE (Blu-ray Disc Rewritable) discs, Kazuya Nakaya of Panasonic's disk drive manufacturing unit said in Tokyo.

For burning data, Panasonic recommends a computer with a minimum of a Pentium 3 700MHz processor, 128MB of memory and 10GB of hard-disk drive space. Drivers will be available for Windows XP, Windows 2000 and the 64-bit version of Windows XP.

Movie playback is more taxing on the hardware, and will have to wait until suitable playback software is available. Optical disc software maker CyberLink showed a pre-release of its playback software in Tokyo.

A high-end PC is needed to watch movies because of the high-bandwidth video stream. In the case of MPEG-2-encoded content, users will need a Pentium 4-based machine running at 3GHz or more. For movies encoded in MPEG4AVC, they'll require a more powerful Pentium D system running at 3.2GHz or more.

The Panasonic drive will be available in Japan as an aftermarket unit from June 10 and will cost around $850. Panasonic has yet to decide on international launch plans.