🚀 go-pugleaf

In article <1990Aug28.185843.23493@murdoch.acc.Virginia.EDU>
sdm7g@dale.acc.Virginia.EDU (Steve D. Majewski) writes:
>   If there is any-one who
> remembers the days before Apples, PC's, etc.: DL was the author of an
> early book on how to build a "TV-Typewriter" ( Now OUT OF PRINT, even
> by the author, I'm sure )

In article <841@ecicrl.UUCP> clewis@ecicrl.UUCP (Chris Lewis) replies:
>I remember it, I may even still have a copy of the schematics or the R-E
>article.  It's just as well it's out of print ;-)
>
>(I'm not denigrating DL, the TVT was one of the pioneering efforts in the
>"do it in software, not hardware DUMMY!" school of controller design.
>But, no, you wouldn't want to do it that way any more....)

Sorry, WRONG!

The original, accept no substitutes TV Typewriter was entirely done in
HARDWARE.  It used shift registers for data storage.  Didn't scroll.
Low resolution (I think 32x16 characters).

But it was fairly cheap to build, and it was the first terminal that you
could put together yourself.  I still have mine, gathering dust somewhere.
I haven't powered it up for 15 years at least.

YOU are thinking of a much later gizmo, such as the TVT-6.  I think that
there was one called TVT-6L.  I got a kick out of that series because Don
managed to sell basically the same design to three different publications,
within a few months of each other.  It was heavily driven by software.  If
I remember correctly, at one point the CPU executed a long string of NOPs,
just to get a nice ascending address on the bus.  Somebody who actually
built one of these can give you more info.

The generation between the original TVT and the TVT-6 was what Don called
"Cheap Video" and "Son of Cheap Video".  Books to match.  Included some
interesting techniques.  Like the "Snuffler Coil", which you placed next
to your TV set to pick up stray pulses from the sync circuitry, so you didn't
have to generate it yourself.