I know this OT discussion is growing but I hope it is of some interest
to fellow MMDers.  I'll stop if you don't like it.

Quadruplex video recorders
- - - - - - - - - - - -  -
Paul West is right.  Ray Dolby and Chuck Anderson did the electronics,
Fred Pfost did the heads.  My faulty memory, maybe I need a new head :)

Video recording without rotating heads
- - - - - - - - - - - - - - - - - -  -
There are not now and have never been any really practical linear video
recording systems. All the ones I know of have been experimental or
never sold any quantity except perhaps the Fisher-Price. I do not claim
this list as comprehensive but I think it covers all the major ideas and
systems.

= Bing Crosby Enterprises - US, Early 1950s. Worked reasonably well but
  never put into production. Then Ampex invented quadruplex.

= BBC "VERA" Video Electronic Recording Apparatus - UK, circa 1957.
  Worked and was demonstrated on air, but not as good as quadruplex.

= Wesgrove - UK, early 1960s. This may have worked after a fashion.

= Telcan - UK, early 1960s. Similar idea to Wesgrove.

= BBC Experimental digital video recorder - UK, circa 1975. Built for
  research use only. Used 1" instrumentation tape recorder with lots of
  tracks at 60 or 120 inches per second.

= Fisher-Price - US circa 1987. This now has a cult following among some
  "alternative" film makers for its strange, grainy and low resolution
  "look" and can now command quite high prices!

= I think there was a system which recorded a track, reversed the tape
  in a hurry and then recorded another one parallel to it and so on. I
  cannot remember who made it, possibly Loewe-Opta.

Jeffrey Borinsky