TRS-80 Model 1 (was: Arty computers (was: Re: PDP-11/70 inYates Center, KS)

[Jim Isbell, W5JAI]

In my original post I did not mention that, but as I recall there was 9K of
volatile memory (tubes) and later we added 144 BYTES of core memory.  To
begin with when we had no non-volitile memory the programs were typed on a
teletype tape and loaded when needed from a paper tape reader following a
boot tape.  A boot progam was added when we got the 144 bytes of core.  That
was the main use of the core to store a boot program.  At one time they
tried a Drum "hard drive"  but it was very unreliable.   The whole process
was very slow sometimes taking a couple of hours to get it booted and
programs loaded due to the unreliability of the tape reader which was very
finicky about the tape speed and the speed was governed by how fast you
pulled the tape through!  Yes, by hand, no motorized tape reader.  Once
booted and a program loaded you could then store and retrieve data from the
Ampex drives but could not store programs or retrieve them from tape.  I
don't know why because it would seem a natural way to do it...in hindsight.

Yes it was an IBM

On 2/4/07, Chuck Guzis <cclist at sydex.com> wrote:
>
> On 4 Feb 2007 at 12:53, Brent Hilpert wrote:
>
> > Given Ampex tape drives, has the "7070" number lead to the presumption
> in the
> > discussion that it was an IBM processor?. Might it be that it was made
> by
> > another manufacturer, and a one-off/special contract that wouldn't
> typically
> > show up in popular lineages?
>
> Maybe someone still has the original message that started this
> thread, but I seem to remember that  there was something in it that
> at least confirmed the 7070 architecture.  I think it was the mention
> of 5K words of core being standard.
>
> Cheers,
> Chuck
>
>
>
>


-- 
Jim Isbell
"If you are not living on the edge, well then,
you are just taking up too much space."