Re: How true...

["Michael J. Mahon" <mjmahon@aol.com>]

bieling@terra.es wrote:
> <http://ericclever.com/6500/TV_Typewriter.html>
>
> I read this book back then, because learning how to build something
> that could display characters on the TV screen (no more, no less) was
> *so* thrilling, but in the end it's true that this project was both
> "extremely ingenious and ultimately misguided", unlike some other "TV
> TypeWriters" that came later... 8-)

The original "TV Typewriter" was all TTL integrated circuits and
shift registers--the 6502-based design was Lancaster's later RAM-
based cost-reduction.

The only "ultimately misguided" aspect that Cleaver refers to is the
consumption of 85% of the 6502's time with video generation, leaving
only 15% for computation.  For a "TV Typewriter" this seems like a
very reasonable tradeoff--after all, it was intended to be a terminal
for *another* computer, and using a 6502 saved a 6545 video controller.

The Spectrum/Timex sub-$100 computers used a similar approach to video
generation with a Z80, and though their speed while displaying was never
great, it was adequate to interest many users.

-michael

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