Vendors agree on magneto-optical disk specs

A group of hardware makers has agreed on specifications for a magneto-optical disk that could challenge the forthcoming rewritable DVD disks.

The group, led by top Japanese electronics vendors including Fujitsu, Hitachi and Sony, expects to submit final specifications for the format to the International Standards Organisation later this year and to ship sample products early next year, a Fujitsu official said last week.

Supporters of the Advanced Storage Magneto Optical (ASMO) format also include Matsushita Electric Industrial, Philips Electronics NV, LSI Logic, Sharp and LG Electronics.

Under the specifications, the ASMO 12-centimetre disk will have a capacity of 6Gb and will be backward-compatible with today's CD-ROMs and DVD-ROMs, the official said.

The vendors played down the challenge that the new format will present to consumer uses of the rewritable, or DVD-RAM, systems, while saying that the ASMO system will be better suited for corporate use.

"The DVD-RAM is great for consumer applications, but the ASMO is great on the computer side, where data integrity, security and rewritability are important," the Fujitsu official said.

The standard bearer of the DVD forces, Toshiba, has no plans to join the magneto-optical camp, saying that the technology is unproven. "It's hard to judge how soon it will become available," said a spokesman.

Backers of the magneto-optical format argue that a DVD-RAM disk will have a limited life because it uses so-called phase-change tech- nology, in which the surface of the disk is heated and changed from a crystalline to an amorphous state when recording data.

By contrast, magneto-optical technology records data by merely realigning magnetic substances coating the disk but does not alter its state. ASMO proponents argue that this method extends the life of the disk, while supporters of the DVD say that it slows down the writing speed of the system.