Sharp and Sony have developed a small, high-density magneto-optical (MO) disc that currently fits up to 1GB of data on a 50.8mm disc. This version uses a conventional red laser to read the disc, but engineers are already working on applying a shorter-wavelength blue laser, which will allow the capacity to be pushed up to 2GB per disc. In contrast, much larger compact discs can hold 650MB of data and the first generation of DVD-ROM discs can hold 2.6GB. The largest of today's memory cards holds 64MB of memory, and 1GB cards are expected to be more than a year away from commercialization. The system is based on the MO removable media format that is commonly used in Japan and its reliability, which is superior to that of optical disc systems like CD-RW and DVD-RW, is why the companies chose it as a base for the new system, said Sony spokeswoman Aki Shimazu. To further increase reliability, the disc will be enclosed within a cartridge to make the entire media 54 square mm and 4 mm thick. The two companies say support for the format, vital if it is to enter into widespread use, has already been pledged by a host of electronics companies including Casio, Fujitsu, IBM, Mitsubishi, Pioneer, Philips and TDK. Together they will promote the format and begin work on a future generation disc that utilizes a blue laser and a 65 mm-diameter disc to provide data storage capacity of 4GB. The system is still under development and the spokeswoman declined to speculate on when it might be launched commercially.