Sony to launch 23GB optical data disk in November

Sony Corp. will launch a new optical disk format in November that allows for storage of up to 23.3GB per disk, the company said today.

The format, called Professional Disc for Data, is being positioned by the Tokyo-based company as a replacement for the 5.25-in. MO (Magneto-Optical) disk format that it currently sells in the professional data storage space. MO has been on the market for around 15 years, and the highest-capacity version sold by Sony can store 9.1GB per disk.

The key to the higher capacity of Professional Disc is in the type of laser used to read and write information from and to the disk.

Unlike MO, CD and DVD formats, which all use red lasers, the new format uses a blue laser. Because the wavelength of blue light is shorter than that of a red laser, the beam from a blue laser, with suitable optics, makes a much smaller spot on the recording layer of the disk. A smaller spot means less space is needed to record one bit of data, so more data can be stored on a 12-centimeter disk.

The disks are enclosed in cartridges to keep dirt and dust off the disk surface.

Sony will put on sale an internal drive, BW-F101, and write-once (recordable) and rewritable versions of Professional Disc media, PDDWO23 and PDDRW23 respectively, in major world markets in November, said Aki Shimazu, a Sony spokeswoman.

The first-generation drive will cost around $3,300, and blank media will cost between $45 and $50 per disk for both types, according to Shimazu and Sony's marketing center for the format. That's roughly the price Sony promised when it first unveiled the format in prototype form earlier this year.

As MO technology continues to improve, Sony has plans to increase the capacity and sustained write-transfer rate of Professional Disc beyond the 23.3GB capacity and 9MB/sec. transfer rate that are features of the first products that will be launched in November.

Sony's road map has two steps. The first is in 2005, when the transfer rate will be increased to 18MB/sec. and capacity increased to 50GB through the addition of a second recording layer in the disks. The second step is scheduled for 2007, when transfer rate and capacity will be doubled again to 36MB/sec. and 100GB, respectively; the latter doubling will be reached by using double-sided disks, said Sony.

The new format is related to the Blu-ray Disc video disk format that Sony launched earlier this year. Both formats store the same amount of data on a cartridge that looks almost identical, with Blu-ray having additional 25GB and 27GB versions, although the data transfer rates to the disks are different. Blu-ray, which is designed to record high-definition television, records at a rate of 4.5MB/sec., or half that of Professional Disc.

These differences mean the two formats, although similar, are incompatible.

While that incompatibility may sound like a disadvantage for consumers, Sony says the two are targeted at different markets, so it shouldn't cause a problem. It also means Sony has full control over the Professional Disc format, which it developed alone, unlike Blu-ray, which is controlled by a consortium of nine companies, of which Sony is one.

"There are certain differences, but it's pretty much the same format," Shimazu said. "There is no compatibility at this point. If you make it a Blu-ray [Disc], you have to ask the eight other companies involved in the project. [Professional Disc] is a Sony exclusive."

A version of the Professional Disc format has already been launched by Sony as part of its professional broadcasting product line under the name XDCAM. That variant uses similar disks but a different data-transfer rate and is aimed at video acquisition, editing and postproduction applications. Despite its similarities with the Professional Disc for Data, the two formats are also incompatible, Sony said.

Sony isn't the only company looking at using blue-laser technology for data storage.

Plasmon PLC has developed its own format, called UDO (Ultra Density Optical), that it's targeting as a replacement for MO. UDO can accommodate 30GB of data on an optical disk that's enclosed in a cartridge made to the same dimensions as current MO cartridges. The U.K.-based data storage systems company plans to develop 60GB and 120GB versions of UDO.

Toshiba Corp. and NEC Corp. are also developing a blue-laser-based format, called Advanced Optical Disc, to store 20GB on a single-layer single-sided disk or 36GB on a dual-layer single-sided disk. It has been proposed by the two companies to the DVD Forum as a next-generation replacement for the existing DVD format.

Copyright © 2003 IDG Communications, Inc.

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