Alpha Microsystems VHS backup working!

From: Vintage Computer Festival <>
Date: Tue Feb 22 19:31:43 2005

On Mon, 21 Feb 2005, Vintage Computer Festival wrote:

> and I was able to pull a tape's worth of files (roughly 30 megabytes). It
> took about an hour and a half to dump. These are 17-18 year old VHS
> tapes, and they're still holding up well.

Actually, it was closer to 10 megabytes: ~500 files, each nearly 24,000
bytes. The software dumped them all into the root directory. The backup
software is fairly retarded in that it requires you to know exactly what
files or directories are stored on the tape, because in order to see
what's there you have to tell it what you want to see, and then if it
exists on that particular tape it'll let you browse the directory. If not
it tells you that your filespec didn't match any files and to try another
one. So if you forgot what directory you may have backed up, you're
screwed! Oi! Also, it only lets you restore files to the same drive AND
directory that you backed them up from! Really dumb!

Another interesting thing about the software is that if it misses a frame
of data it'll catch itself and let you know. Each block is numbered and
the block number is embedded in the block. The software will show you
what block it just read and what block it wanted, so you can manually
rewind the VCR to get it back to where it should be and the backup
software then picks up where it left off and continues restoring. This is
a fairly nice aspect of the software, as the alternative would be to just

I have the Alpha Microsystems Videotrax VCR which is a modified Sharp VCR
with a built-in computer interface. This allows the backup software to
control the VCR: rewind, fast forward, play, stop, even record so you can
do unattended backups. Also, if the link is connected and the backup tape
loses its place, it can automatically rewind the tape to get back in sync.
Cool! Just gotta figure out what orientation I should plug in the ribbon
cable I have, since it's not the original cable and is not keyed at any
rate. I don't want to blow anything on the PC board or the VCR interface.

The actual Alpha Microsystems computers (AM-1000, AM-1200, AM-2000, etc.)
usually have built-in VCR backup jacks, and the higher end ones have the
VCR link as well. AM pioneered using VHS tapes as a backup medium and
really developed it into a cheap but realiable method for backing up huge
volumes of data in an era when equivalent backup systems were big bucks
and required expensive data carts. They also used to distribute OS
updates on VHS. I have several of these in my AM software/documentation

The PC-based system was sold briefly in the 1986-1987 timeframe but
apparently didn't gain much traction, and is very rare. It literally
took me a couple years to accumulate all the pieces I needed to get it all

Corvus also made a VCR backup system which they sold both for their
systems and for other systems. I remember the first demo I ever saw of a
VCR backup system was Corvus' system at Applefest '89.

Sellam Ismail                                        Vintage Computer Festival
International Man of Intrigue and Danger      
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Received on Tue Feb 22 2005 - 19:31:43 GMT

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