IOMega Bernoulli Box 10MB
IOMega was a company famous of their
Zip and JAZ
drives, which allowed to store large amounts of data on a portable
media. However, they haven't started with ZIP - the first IOMega product
was called Bernoulli Box. Released in 1983, the Bernoulli box was a
high-capacity magnetic drive with removable disk cartridges. It was
8-inch and allowed to store 10MB of data on an elastic platter in
hardened cartridge. The principle of operation was revolutionary as of
its time - instead of heads having constant contact with a disc, the
Bernoulli disks used a cushion of air to maintain head right above the
surface. This phenomenon, working on Bernoulli's principle, gave the
name to the drive.
The heads were loadable, and while hard drives used a contact heads with
servo motors, Bernoulli drive used flying heads with voice coil
mechanism, giving better tracking precision by using feedback to
position the head over track.
After 10MB, a 20MB Bernoulli drives have been manufactured, later there were larger disks and drives. In 1987 a Bernoulli Box II has been made, later even with smaller media dimensions, in 5.25" form factor. The technology had a few drawbacks - first, it was extremely sensitive to dust particles. The foil disc itself was kept in enclosed cartridge, while the drive had a fan, but not only for cooling - it was used to maintain positive air pressure inside drive's casing making all dust particles go outside. To avoid injecting dust into the casing, the fan was equipped with special replaceable filter. The filter was not perfect, but head was immune to some smaller particles. However, every now and then, it was needed to clean heads. It was done using a special cleaning cartridge which was placed in a drive and the handle had to be manually moved a few (tens) of times.
This technology was expensive - such drive's cost was like a cost of a complete PC with a hard drive, and cartridges were expensive too, but the reliability, speed of operation and replaceable cartridges was a huge advantage when portability was a key factor, e.g. in backup purposes, CAD and publishing or archiving. IOMega released other mass storage products: ZIP and JAZ drives, Ditto tape drive and even "pocket floppy" or CD-RW drives as well as numerous external hard drives and drive arrays. In 2008 they were acquired by EMC, later Lenovo/EMC.
|Type: Magnetic drive with replaceable disc cartridges|
|Capacity: 10MB per cartridge|
Notice the voice coil mechanism with PCB and the pressure chamber with transparent plastic cover.
My unit's history is not known (bought on a flea market), but I found that it had an explosion inside - two Tantalum capacitors gave up and blown with fire, damaging part of regulator circuit (input chokes) and motor cables. I found parts of a cartridge inside - maybe it was damaged when the capacitors fired and there was a problem to remove it? The parts are various plastic shards, a complete disc (!) and a top sticker.
The drive has quite significant intelligence inside - there are numerous
self-test routines in ROM, and serial port for diagnostics. Everything
in fact is a Z80-based system, supported with glue logic and proprietary
chips made for IOMega.
Electrically the interface is a SCSI, but quite limited - pins 20-34 are not connected, except ATN pin in some units. I don't know how much SCSI-compliant it is with protocol, but there are DOS drivers for it. Under Windows 3.x, there are rumors that IOWare works for it.
After powering up and locking the lever, it should start spinning the hub blinking the green LED faster and faster. If it doesn't, the problem may be in a lever switch, as it's made of foil membrane quite weak after >30 years. The voice coil mechanism is not easily accessible, but its bearing can be checked after opening the logic board - it should be rotating very smoothly, as the coil is made as a track on a movable PCB.
- Service manual
http://bitsavers.informatik.uni-stuttgart.de/pdf/iomega/ - Documentation in Bitsavers server
https://www.brutman.com/Bernoulli_Box/Bernoulli_Box_A220H.html - Description of a 20MB double-drive unit
http://www.obsoletemedia.org/bernoulli-disk/ - Description of cartridge in another collection