1 Jul
2007
1 Jul
'07
5:13 p.m.
From: Dave McGuire <mcguire at neurotica.com>
On Jun 30, 2007, at 10:48 AM, dwight elvey wrote:
Hi
I don't think that would work. First, the calculator had no RAM other
than the delay lines. The metal tape had 2 rows of holes, one was
clock and the other was the data. The motor that ran the tape was
just a free running DC motor. The only thing I could think is that it
may have buffered just a few bits and then burst them into the
delay line as the slot for them curculated around. I suspect that the
delay line was slower than a single bit of the tape but faster than
4 or so bits of the tape.
Remember, the delay line has a fixed delay. The tape had a variable
delay. It ran faster as the tape got near the end. There was
no speed control on the motor. I was curious about this at the time
and confirmed it with an oscilloscope.
Dwight
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I remember writing programs for on of these to
solve a statitical problem
for data on a mass spectrometer. I recall waiting on power up while
it loaded the data from the metal tape( sometimes it needed to be
rebooted ).
I'd love to find one of these. I alway wanted to see how they dealed with
the different speeds of the metal tape and the memory. There was no
exact speed control on the metal tape. It just ran from the spool speed
with no capstan.
I'd imagine they just used a phase-locked loop for clock recovery and
clocked the data into the machine asynchronously. Is it more complex than
that?