[vcf-midatlantic] talk at VCF-East on audio cassettes for data

William Sudbrink wh.sudbrink at gmail.com
Thu May 3 16:45:45 EDT 2018

At one time in the past, I was thinking about doing a VCF exhibit, displaying the "secret messages" in Tomita's _Bermuda_Triangle_ album, using a Tarbell (note that the album notes call it TARBEL (one L) format) S-100 interface card and a real vinyl record.  I figured I could blow a bunch of young minds all at once.  Not only "that great big box with blinking lights is a _personal_ computer?" but also "you used to listen to music with those big black frisbies?". I have a working, double soldered, Tarbell model 1001.  Now that vinyl is getting "hip", I guess I lost my chance.  Or maybe it would be better?  Maybe next year.

Bill S.

-----Original Message-----
From: vcf-midatlantic [mailto:vcf-midatlantic-bounces at lists.vintagecomputerfederation.org] On Behalf Of Herb Johnson via vcf-midatlantic
Sent: Thursday, May 03, 2018 3:11 PM
To: vcf-midatlantic
Cc: Herb Johnson
Subject: [vcf-midatlantic] talk at VCF-East on audio cassettes for data

I've agreed to give a casual talk at VCF-East, on the use of audio cassettes and recorders for program storage on first-generation (1970's) vintage computers. I'll describe how a "TTL logic gate" can create audio waveforms and interpret them, with little more than software and hardware. I'll try to point to early Altair/IMSAI class S-100 computers, early COSMAC (RCA 1802) computers, possibly others. I'll try to reference the earliest efforts to create various standards. And I'll point to current recovery work on some old cassettes.

I'll likely point to various Web pages for details and images - no PowerPoint presentations, no exciting videos. Maybe one wailing audio tape. Some stuff I won't know - I have an idea about that.

So why do this? There's recent and successful efforts, to recover programs today from COSMAC tapes 40 years old now - that's interesting. 
Many period micros are operated today, with MPEG music players acting as the audio source; so it's still in use that way. I mentioned the techie bits of cassette storage and retrieval - I'll draw some schematics. And unfortunately, experience with audio cassettes is becoming "lost" - a generation of young adults have NEVER handled such a thing. (shrug) so it's a teaching moment for those folks.

Unaccustomed as I am with public speaking (snort!), I'll welcome some discussion from the audience.  I'm sure some attendees to VCF-East will know more than I, about some part of vintage-time use (or modern use) of audio cassettes for data. So people with an interest or experience, may want to think in advance about what they might say, bring props, whatever; but keep to the point and be brief.

I'm simply making a point, that cassettes-as-storage was a REAL THING that mattered with first-gen microcomputers; it wasn't that hard; and these things are surviving pretty well.

One thing I'd like to hear from others about, was the volume of cassettes available for 1980's video-gaming "systems", for instance the Timex/Sinclair 1000. Early Apple IIs and TRS-80's used cassettes. Those systems weren't on my radar at that time.  My impression is that a lot of little companies, computer clubs, individuals, distributed bunches of those program cassettes in the period. If anyone remembers cassettes for their system, consider speaking up at the talk.

If you are so moved about some notions on the subject, email me via my retrotechnology.com site. A Web search of my domain will find plenty of cassette material, but it might spoil any surprises from my talk! ;)

Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net

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