[Leica] Another in the Computer History Museum series

[jhnichols at lighttube.net (Jim Nichols)]

Thanks, Herb.  Our first wind tunnel data reduction computers used drum 
memory such as this.  In our case, there was no smoking allowed in the 
computer rooms.  I think they came online about 1954.

Jim Nichols
Tullahoma, TN USA
----- Original Message ----- 
From: "Herbert Kanner" <kanner at acm.org>
To: "Leica Users Group" <lug at leica-users.org>
Sent: Friday, January 18, 2013 10:51 PM
Subject: [Leica] Another in the Computer History Museum series


> In the early 1950's, there what was called the "Cold War". With the 
> realization the that Soviet Union had nuclear weapons and bombers capable 
> of getting here via the North Pole without refueling, some kind of defense 
> system became mandatory. The SAGE (Semi Automatic Ground Environment) 
> System, a multi-billion dollar system was developed. It had twenty one 
> main sites. The computers, which received radar information and then 
> directed fighter places, had forty-nine thousand vacuum tubes. Because 
> this system was to be operational 24/7, each site had two such computers, 
> and the magnetic drum memory units in the two were updated often enough so 
> that they could switch computers and the guys on what looked like radar 
> displays wouldn't know that they had switched. Here is the console of one 
> computer.
>
> http://gallery.leica-users.org/v/herbk1/L1002792.jpg.html
>
> Here is a typical display unit that simulates a radar. If you look large 
> at the left side of the desk, you will see an ashtray and a socket for a 
> cigarette lighter (sign of the times--they didn't want the soldier to 
> leave the console for a cigarette break).
>
> http://gallery.leica-users.org/v/herbk1/L1002795.jpg.html
>
> There are several ironic facts about this muliti-billion dollar project. 
> First, the last of these units was decommissioned in 1983. For several 
> years prior, the threat was not bombers; it was intercontinental ballistic 
> missiles, for which this system was useless. Well before 1983, the West 
> was not manufacturing vacuum tube; every thing was transistorized. Guess 
> where we got the replacement tubes. From the Soviet bloc!
>
> The next image shows a tiny fraction of a computer at MIT called 
> Whirlwind. It was the progenitor of SAGE. It also has an interesting 
> story, which is all about a remarkable guy named Jay Forrester. He was not 
> only an inventor, but an incredible project manager an negotiator. It all 
> started around 1946 when the Navy wanted a flight simulator to use as a 
> pilot trainer for planes that had not yet been built, but that were on the 
> drawing boards. They believed they knew the flight characteristics. 
> Because the only existing digital computer was much too slow, it was clear 
> that it had to be driven by an analog computer. But those are hideously 
> difficult to program, and soon Forrester realized that the task was 
> impossible. It had to be a digital computer, but the several existing ones 
> were still much too slow. So Forrester set himself the task of speeding up 
> digital computers by reducing the word size and performing many operations 
> in parallel that used to be performed serially. I sa
> w this computer--my best guess was in 1953. It was imposing. Three of the 
> four walls of the room were filled with panels plugged with vacuum tubes. 
> There was a very large cathode ray display tube on which "real-time" 
> displays could be seen. A favorite demo was the display of the path of a 
> bouncing ball. The image below was cooked up by the Museum to show the 
> front of a few panels and their vacuum tubes, and the rear, showing 
> components and wiring.
>
> http://gallery.leica-users.org/v/herbk1/L1002818.jpg.html
>
> Whirlwind initially had a memory consisting of a bank of cathode ray tubes 
> (William's Tubes), a fast but unreliable memory. Someone called to 
> Forester's attention a new thingy called a "magnetic core," being used to 
> temporarily store bits in something called a "shift register" in a 
> computer at Harvard. Forrester disappeared into his lab for about eight 
> months, and came up with core memory. This became the standard computer 
> memory for the next twenty years until semi-conductor memory was invented.
>
> When the Navy lost interest in flight trainers, Forrester persuaded them 
> that Whirlwind was the prototype for a Command and Control computer, aka 
> "Combat Information Center". There was a new contract. When that petered 
> out, he persuaded the Air Force that the computer could be an air defense 
> device. The tipping point was the "Cape Cod Experiment". There were enough 
> radars around that area to permit a demonstration where bombers would 
> "attack" Cape Cod and Whirlwind operators, using radar information, would 
> direct fighters to the bombers. This demonstration was so successful that 
> it launched the development of SAGE. IBM was the prime contractor; this 
> put IBM solidly in the computer business.
>
> Herbert Kanner
> kanner at acm.org
> 650-326-8204
>
> Question authority and the authorities will question you.
>
>
>
>
>
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