1 Sep
2023
1 Sep
'23
5:53 p.m.
Just to add, interestingly, Singer also purchased General Precision from Librascope.
Librascope/General Precision were the folks that had earlier acquired Royal-McBee.
Royal-McBee developed the wonderful (some consider the first "personal"
computer) LGP-30 vacuum-tube, magnetic drum computer that was designed by Manhattan
Project theoretical physicist Stanley Frankel.
Frankel had quite a legacy in the world of computing, having contributed to the design of
the delay-line-based Packard Bell PB-250(with Max Palevsky), and development of a custom
high-speed computer for Continental Oil Company called CONAC (used for data reduction of
sounding operations search for oil deposits).
Frankel also developed an early electronic calculator design that was purchased by Smith
Corona/Marchant (SCM) and produced as the CRT-display SCM Cogito 240 calculator, augmented
with Square Root as to Cogito 240SR.
Frankel also collaborated with SCM on the development of the logic for the first set of
LSI integrated circuits that were used in the later Nixie-tube display Cogito calculators.
He also developed a very interesting calculator, based somewhat on the principles of the
LGP-30 computer for Diehl in West Germany. The machine was fully transistorized and used
only 142 transistors in its logic. It was based on magnetostrictive delay lines (two of
them), and was a fully microcoded architecture, I believe the first electronic calculator
to be completely microcoded.
Since read-only memory (for the microcode) was either physically very large, or complex
and expensive to build at the time (diode ROM, wire rope ROM), the microcode was loaded
into the calculator at power-up time from a two channel punched metal tape. One channel
provided the clocking, and the other channel provided the bits.
It took just under a minute from when the calculator was powered on until the microcode
was loaded into a delay line, and from there, all operations of the machine were
controlled by the microcode in the delay line.
The machine was able to be implemented with so few transistors because the microcode word
was quite wide, and was designed so that it was sequentially interpreted as the bits
streamed out of the delay line, so not all that many flip flops were needed. Working
registers were stored in the other delay line, along with program steps (yes, the machine
was programmable).
The design was very elegant. The machine debuted as the Diehl Combitron, and the cool
thing about its design was that it was really easy to augment by just changing the
microcode tape (which was quite easily done...bugfixes could be easly installed even by
end-users, though such was discouraged).
Soon after the Combitron was introduced, an augmented version was introduced called the
Combitron-S that added a small amount of I/O circuitry and additional microcode to
implement operations to allow the addition of an external punched paper tape
reader/punch.
An interesting aspect of electronic calculator history is that there are a number of
people whose names pop up at various points in time during the evolution of the
technology. Frankel was one of those, along with a cast of a few others, all of whom had
major impacts in the realm of electronic calculator (and the eventual evolution of the
electronic calculator into what became the microcontroller/microprocessor that spurred the
development of the personal computer).