Sony will launch a new optical disc format in November that allows for
storage of up to 23.3GB per disc, according to the company.
The format, called Professional Disc for Data, is being positioned by the Tokyo
company as a replacement for the 5.25-inch MO (Magneto-Optical) disc 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
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 disc.
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 disc. A smaller spot means less space is need to record one
bit of data and so more data can be stored on a 12-centimeter disc.
The discs are enclosed in cartridges to help keep dirt and dust off the disc
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 from November, said Aki Shimazu, a spokeswoman for Sony in
The first-generation drive will cost around ¥360,000 ($3,300) and blank media will
cost between $45 and $50 per disc for both types, according to Sony's marketing
center for the format and Shimazu. 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 and 9MBps that
are features of the first products that will be launched in November.
Sony's roadmap has two steps, the first in 2005 when transfer rate will be increased
to 18MBps and capacity increased to 50GB through the addition of a second recording
layer in the discs. The second step is scheduled for 2007 when transfer rate and
capacity will be doubled again to 36MBps and 100GB, respectively; the latter through
the use of double-sided discs, said Sony.
The new format is related to the Blu-ray Disc video disc 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 discs are different. Blu-ray, which is
designed to record high-definition television, records at a rate of 4.5MBps per
second 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," said Shimazu.
"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
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 discs but a different data transfer rate and is aimed at video
acquisition, editing and post-production applications. Despite its similarities with
the Professional Disc for Data, the two formats are also incompatible, said Sony.
Sony is not the only company looking at utilizing blue laser technology for data
Plasmon Plc, a Cambridge, U.K.-based data storage systems company has developed its
own format, called UDO (Ultra Density Optical), that it is also targeting as a
replacement for MO. UDO can accommodate 30G bytes of data on an optical disc that is
enclosed in a cartridge made to the same dimensions as current MO cartridges. Its
future roadmap includes 60GB and 120GB versions of UDO.
Toshiba Corp. and NEC Corp. are also developing a blue-laser based format called
Advanced Optical Disc (AOD), the format can store 20GB on a single layer, single
sided disc or 36GB on a dual layer, single sided disc. It has been proposed by the
two companies to the DVD Forum as a next-generation replacement for the existing DVD