Toshiba Corporation has announced a prototype optical disk drive system that achieves the large storage capacity, high data transfer rate, overwritability, simple structure, and compact size required for sophisticated, next generation personal multimedia systems. The new drive's double-sided 3.5-inch phase-change optical disk can store 1.3 gigabytes (GB) of data. Its versatile operation allows data to be transferred at a rate as high as 16.4 Mbps, and new data can be written over previously stored data without prior deletion. As an optical device, the new drive is free of the magnetic components that add to size and weight, allowing configuration of a compact portable system.
Toshiba's new technology provides the basis for commercialization of large capacity, overwritable optical disk drive systems for next generation multimedia systems. The company expects to launch its first products based on the technology in late 1995. It will take full advantage of the simplicity of the phase-change design to produce compact, light, very competitive systems. The company is also confident that the potential in the phase-change design will allow significant further increases in storage capacity, to around 5 GB in the 3.5-inch format and around 12 GB in the 5-inch format, while maintaining system compatibility.
Advanced multimedia systems must store and transmit at high speed large volumes of data, including such information-rich sources as video, and must do so while offering the small size, portability and ease of use of current storage devices. However, no currently available drives, whether magnetic or magneto-optical, offer a solution embracing all the elements of compact size, large data volume, transferability, high transmission speed, and overwrite capability. Among other drawbacks, none of them offers gigabyte-plus capacity on a single 3.5-inch disk.
Toshiba's new prototype is based on a phase-change optical disk. The company has already established the potential of this technology with a 500 megabyte capacity system, and with its new prototype achieves the world's highest capacity of any optical disk systems: 1.3 GB of data on a 3.5-inch disk, equivalent to two CD-ROM discs. Data can also be overwritten with new data by making use of the laser's ability to transform the surface layer of the disk from an amorphous to crystalline phase, and vice versa, offering a storage medium with capabilities far exceeding those of other systems. …