History (1989): Bosco Drive From Bernoulli Optical Systems

At the AIIM Show in San Francisco, CA, in June, on ICI Imagedata booth, a live technology demonstration of flexible optical disks based on Digital Paper media took place.

We saw an example of a prototype drive under development by the Bernoulli Optical Systems Company (Boulder, CO), a subsidiary of Iomega.

The new drive mounts the WORM flexible optical disk on a hub, which is adjacent to a specially formed Bernoulli plate on a common axis. As the disk spins, the plate channels the air flow and increases its velocity, causing a pressure differential which lifts the disk towards the plate. At a given speed the spinning disk is stabilized by the air flow, causing it to fly in very close, stable proximity to the optical head. The disk-head separation is of the order of one micron.

In comparison with optical disk drives, the benefits are: a light weight fixed focus replacing the heavy focusing servo; a servo system tracking replacing the secondary fine positioning mechanisms. Flying the head close to the surface allows as high numerical aperture low mass lens to be used, delivering more power to the disk from the laser and so increasing the data rate. The air flow also eliminates the danger of head crash, because if the pressure differential is lost, the head and media separate instead of colliding.

With this technology two disks can be spun in the same cartridge and each addressed with its own head, thus doubling the capacity of the drive compared with rigid disk systems.

Other benefits are removability, indelible recording, archival-like permanence and cartridge protection and handling.

OEM evaluation unit of the 5.25-inch half-height will be available in 1FQ90 and production will begin in 2Q90.

The average access time should be 40ms and transfer rate 1MB/s, on account of the ZBR technology adopted.

Total capacity ought to reach 1.3GB in a disk placed in a cartridge almost identical to the ISO 5.25-inch optical disk cartridge.

According to a spokesman on ICI’s booth, the cartridge will cost less than $50. The drive has not been priced yet but should cost about the same as the magneto-optical ones on the market.

This article is an abstract of news published on the former paper version of Computer Data Storage Newsletter on issue ≠18, published on July 1989.