VHS Tapes as storage.

From: Rick Bensene <rickb_at_bensene.com>
Date: Mon Feb 10 17:23:01 2003

> "Andrew Strouse" <kittstr_at_access-4-free.com> said:
> > Hi, I seem to remember reading in popular electronics, about software
> > would let you use a vcr to backup your computer. I think it was about
> > years ago. Does anyone remember or know anything about this. My
searches on
> > google have turned up nothing. Thanks for any help you can provide!

I don't have any reference to what you're looking for, but do have a story
such technology.

Alpha Micro had a board that would go into their early systems that would do
just that.
There was an AMOS application that would do automatic unattended backups to
standard VHS tapes.

A company that my wife worked for years ago used Alpha Micro (I believe they
were S100 bus
machines with a Western Digital microprocessor that was PDP11-like -- I
think it the system was
called an AM-100?) system for a custom-written system (in Alpha Micro's
powerful BASIC compiler environment)
that managed all aspects of patient records management and billing for
institutional pharmacies (nursing homes, hospitals, etc.).
Timeframe was probably the early 1980's, if I remember correctly.

The system, as I recall, had a big S100 chassis stuffed with boards,
including multi-port serial boards,
lots of memory, an SMD disk intefrace (that hooked up to multiple CDC Hawk
14" drives (later upgraded to
Fujitsu Eagle), and a special card that fed video out to the VHS VCR for
tape backup. The VHS backup
system worked pretty well, but they eventually had more data than could be
held on one tape, so they ended up
going with another type of backup technology. As a result, they had a ton
of used VHS tapes that they just put
out in the employee lunchroom for people to take. My wife brought home a
few thinking that we could just use
them as 'scratch' tape sto record TV onto. I was curious, so I stuck one of
them in my VCR and pushed "PLAY".

The resulting display on the TV was quite interesting. Apparently the
'backup' part of the nterface card
was nothing much more than a small video system, with a frame buffer memory
and video interface
circuitry. The video was just a pattern of bits that showed up as black and
white rectangles (not at
tremendously high resolution) on the screen, with a series of static
patterns on the first few rows (framing data?)
followed by a bunch of random bits (payload), followed by more (different)
static bits that probably served as an
'end of frame' indicator.

The 'restore' aspect of the board was probably fairly simple circuitry to
pick out the framing and payload data from
the video stream, and ship it back to the application in byte-sized chunks.

Interesting technology. Seems to me that with today's fancy video boards
that have video digitizers built into them,
it wouldn't be too tough to reproduce this technology using such a video

Rick Bensene
The Old Calculator Web Museum
Received on Mon Feb 10 2003 - 17:23:01 GMT

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