Prodisc has developed a DVD-R disc that can hold 200MB more data than current discs and plans to unveil it at next week's Computex show in Taiwan. The disc has a capacity of 4.9GB, versus 4.7GB for a conventional DVD-R. The extra capacity was realized by reducing the gap between the successive turns of the disc's spiral recording track. By reducing the gap, (track pitch), a longer track can be fitted onto the disc and so more data can be stored.

Because the track pitch has been changed, the new disc won't be compatible with all current DVD drives. Fifteen drives from major drive makers offer full support for the disc, which means allowing storage of up to 4.9G bytes, said Bryan Huang of Prodisc's storage media research and development department.

The company has an additional list of about 100 drives which offer partial support, such as allowing storage up to 4.7G bytes only or slower recording speeds. An additional 26 consumer DVD-R video recorders also offer partial support.

Prodisc, based in Taiwan, hasn't determined if the disc meets the DVD-R specification, which allows for a certain margin of error in track pitch, said Huang. The DVD Format Licensing and Logo organization, responsible for issuing licenses that allow the use of the DVD logo, said it has yet to receive compliance testing information for the disc and so can't make a judgment.

The 15 drives with full support are:

Behaviour Tech Computer (BTC) DRW1108IM
BenQ DW1620
LG GSA-4082B and GSA4120B
Lite-On SOHW-1613S
NEC ND-3500A
Optorite DD0401
Pioneer DVR-107D and DVR108
Plextor PX-708A and PX-712A
Ricoh MP-5308D
Samsung SH-W08A
Teac DV-W58D
Toshiba SD-R5272