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 LGP-30 in FPGA 
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Joined: Wed Jan 09, 2013 6:54 pm
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Here's a recreation of the classic affordable desk-sized drum-based machine which features in The Story of Mel:

Last edited by BigEd on Mon Sep 10, 2018 3:27 pm, edited 1 time in total.

fixup link rot

Mon Oct 31, 2016 8:47 pm
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Joined: Tue Jan 15, 2013 5:43 am
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Very nice! But -- no offense -- the original machine is even more fascinating. Here's the original LGP-30's version of a "front panel" display. It's quite a stylistic contrast with the LED's that replaced it!
(from a link provided by the builder of the replica)

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Sat Nov 05, 2016 1:59 am WWW

Joined: Wed Jan 09, 2013 6:54 pm
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Thanks Jeff! I see mentions of a Pi program - also, you've found a computer history museum, in Stuttgart, not already on the world map.

Here's another description of the machine:
The main memory consisted of a magnetic drum with a capacity of 4096 thirty-two-bit words arranged in sixty-four tracks of sixty-four sectors each with one word in a sector. There were three circulating registers: the Accumulator Register for arithmetic operations, the Instruction Register for holding the current instruction, and the Control Register which held the address of the next instruction to be executed. Input and output was by means of a Flexowriter, an electric typewriter with a ten-character-a-second paper tape reader and punch. The contents of these three registers could be viewed as binary numbers on a small CRT display. The clock speed was 120 kilocycles giving addition and multiplication times, inclusive of storage access, of 8750 and 24 000 microseconds, respectively. Recommended staff for an eight-hour shift was one maintainer-operator and a part-time programmer. Approximately 500 LGP-30s were manufactured and sold.
A somewhat complicated procedure was required for preparing the LGP-30 to accept programs and data. A first bootstrap program of five instructions was manually keyed into memory. This program allowed a second bootstrap program to be read from paper tape which in turn read a program input program also punched on paper tape. This last program permitted the input from tape of the user's program as a sequence of decimal commands with the operation codes as alphabetic characters and the data as decimal numbers. The commands and data were converted on input to binary. Fortunately the manufacturer supplied a tape with the second bootstrap and input programs.

The above, and much more besides, found in a little history, concerning the first computer in Canada:
In early 1957 there was only one programmable electronic computer in all of Canada. This was FERUT, a one-of-a-kind computer custom-built at the University of Toronto by Ferranti Electric Co. of Manchester. It was built using World War II vacuum tubes and occupied a large room in the McLennan Laboratories in the Department of Physics. Input and output was by five-hole punched paper teletype tape. The machine had the capacity of one of today's programmable pocket calculators, but was much less reliable. A crew of eight engineers was required to maintain FERUT, but in spite of six hours of scheduled preventative maintenance each day, the computer could not be depended upon to run without failure for more than half an hour or so. Nevertheless, FERUT was a marvel of its day.

and, relating to the LGP-30:
Stanley Frankel, who joined the Los Alamos project, was one of the persons overseeing the hand computing group, where his wife was one of the hand computers, and later the IBM installation. After the War was head of a digital computing group at the California Institute of Technology, responsible for the logical design of the MINAC computer which was subsequently licensed to Librascope, Inc. and built and marketed as the LGP-30. The MINAC, Minimal Automatic Computer", was a small computer occupying one square foot of floor space, had 90 tubes and 900 crystal rectifiers and was intended for general-purpose scientific and engineering calculations.

And on the acquisition of an LGP-30:
We have seen that in the mid 1950s professional and academic computing needs at the University of Alberta were being met by mathematical tables, mechanical and electromechanical calculators, slide rules (of course), and then by a few adventurous physicists using the University of Toronto's electronic computer. In May, 1957 the President, Dr. Andrew Stewart, appointed a "Committee on Electronic Equipment". In July the Committee recommended unanimously the purchase of an LGP-30 General Purpose Computer from the Royal McBee Corporation of Port Chester, New York at a price of forty thousand dollars.

The University of Alberta was the third Canadian university to acquire a computer. The first was the University of Toronto which in 1948 started to design and build its own computer which was operated briefly and then replaced in 1952 or 1953 by the FERUT computer. The second Canadian university to get a computer was the University of British Columbia which acquired its computer in March 1957. In 1966 thirty-three Canadian universities had computers.

The machine was very useful:
An indication of the scope of research opened up by this latest University acquisition may be gained from the following illustration: An average type problem undertaken by a theoretical physicist used to take about one month to solve through the use of a desk calculator. Now, the same worker need spend about one day preparing his material to meet machine operation requirements. Actual computations will take about one hour. Many problems which formerly were considered too time consuming to attempt can now be tackled without hesitation.

That history found on a page with a link to an LGP-30 simulator in 270 lines of J.

Sat Nov 05, 2016 7:04 am

Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1786
I see Jürgen Müller's project has now moved on from a compact calculator-style format to a more faithful but still hand held style:


Lots of source files there, and links to instructions as to how to program the machine.

Just 15 flip-flops in the original! You can see the front panel top left of the main unit to the right:


Sat Feb 11, 2017 11:53 am
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