"Oddball"(LGP-30)

[dwight elvey]

>From: Dave McGuire <mcguire at neurotica.com>
>
>On Jun 30, 2007, at 10:48 AM, dwight elvey wrote:
>>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?

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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