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In their heyday, analog computers handled heavy-duty math, scientific and industrial applications.
Analog computers had their heyday from about 1940 to the late 1960s, but their important legacy lives on. According to a Wikipedia definition, “An analog computer is a form of computer that uses the continuously changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities symbolically, as their numerical values change.”
Most were designed for very specific applications, like heavy-duty math or flight component simulation. Here’s a look at just a few -- there were many, many more examples -- of some of the cooler analog computers.
Here we have an IBM System/7 introduced in 1970. The box featured a 400-nanosecond cycle time; 16-bit word length with byte parity checking; and 2,048 to 16,384 words of monolithic storage in 2,048-word increments. According to IBM: Monthly rental was $352 for the smallest IBM System/7, including the processor, 2,048 words of monolithic memory and one input-output module.
The purchase price was $16,060. Additional memory increments of 2,048 words rent for $105, or can be purchased for $3,675. The first customer delivery of an IBM System/7 was made on Sept. 16, 1971, to American Motors Corporation (AMC) at Kenosha, Wis.
Systron-Donner Series 80
According to the Computer History Museum, Systron-Donner computers arrived late to the analog game and were utilized in very specific applications such as education or training. According to Glensmuseum.com Systron-Donner Series 80, first shipped in 1964, is the Cadillac of general-purpose analog computers and was transistor based instead of tube based as most of its contemporary analog computers.
Ford Instrument Mark Fire Control Computer
One of the longest lived and most used analog systems was the Ford Instrument Mark Fire Control Computer system used by the United States Navy on ships from World War II to 1969. In its earliest configuration the computer was 3 feet wide, 4 feet tall, and 6 feet long and weighed nearly 3,000 pounds. The system was used to target, aim and fire the big guns of a battleship or destroyer.
Goodyear Electronic Differential Analyzer
From the online Analog Computer Museum: About 1948 the Goodyear Aircraft Corporation began moving into missile development and needed analog simulation equipment to aid in missile design. With the Goodyear Electronic Differential Analyzer line of analog computers, the Goodyear Aircraft Corporation was an early force in the development of the electronic analog computer.
The Jerie analog computer
One of the more famous special purpose analog devices was one developed by Professor H. G. Jerie of the International Training Centre for Aerial Survey (ITC) in Delft, the Netherlands in the late 1950s. The system could handle the equations necessary to bring together multiple images and solve mapping and surveying problems.
HITAC (HItachi Transistor Automatic Computer)
Shown here is a picture of the Hitachi (model 303E). Hitachi analog computers were likely most famous as large flight simulators for Japanese defense systems through the 1950s and into the 60s.
General Electric differential analyzer
Some of the most widely used analog computers where known as differential analyzers. This picture of a General Electric differential analyzer comes from the UCLA engineering school which defined the machine as an “interconnected system of shafts, motors and gears, and electromechanical elements. The machine employs these mechanical elements, whirring, buzzing, and clicking away, to perform addition, subtraction, multiplication, and division, and the electromechanical elements for more complex functions.
“One of the most important elements of the differential analyzer is a Polaroid photoelectric system of unique design which GE developed. Fourteen of the highly sensitive devices are installed on the machine, thus permitting the accurate, speedy solutions of differential equations requiring as many as fourteen simultaneous integrations.”
Newmark analog computer
A 1960 Newmark analogue computer which comprised five components was used to solve differential equations.
Beckman Instruments EASE
This particular Beckman Instruments EASE analog computer was 60 feet long and had a push button control panel. According to the Computer History Museum, this one was used by the Allison division of General Motors to design jet engines circa 1962.
One of the most famous analog computers was the Norden bombsight, a mechanical analog computer made from gyroscopes, motors, gears, mirrors, levers and a telescope. It could both pilot the aircraft and determine when to release its payload.
According to the Computer History Museum, “Inventor Carl Norden sold his interest in the bombsight to the government for only $1. His invention proved critical to successful high altitude daylight bombing during WW II. Although considered a military secret during the war, some later studies refuted the claims of its great accuracy.”