[SIGCIS-Members] whirlwind, radar and real-time tracking

Pierre Mounier-Kuhn mounier at msh-paris.fr
Fri Apr 23 16:19:18 PDT 2021

Hello Guy,

As you certainly know, Whirlwind is considered to be the first digital computer designed for real-time computing, particularly for radar tracking and interception guidance or assistance to tactical decision. 

I have studied air-defense systems in Europe, particularly in France: The first projects involving digital computers did not appear before the mid-1950s, at IBM France and in a small Paris company, SEA, which was also developing digital control devices for machine-tools. At that time, several similar digital computing projects were being developed, in the USA of course (at GE, in the US Navy with Univac, etc.) but also in Britain and in the USSR.

It is true that "innovations like this rarely occur in a complete vacuum": The Whirlwind was built at MIT, one of the world's richest environments for innovation in electronics and defense systems, which had worked on a previous analogue calculator project for the US Navy. Air defense systems already existed, based on radars, telecom lines, control rooms and command centers: The idea to replace manual operators with a computer to process signals and make decisions faster "naturally" came to various people in the context of the Cold War. The Whirlwind was nevertheless a leap forward in technology, logical design and use.

Hoping that these simple remarks help you.
Pierre Mounier-Kuhn   
CNRS & Sorbonne Université, Paris  

----- Mail original -----
De: "Guy Fedorkow" <guy.fedorkow at gmail.com>
À: "members" <members at sigcis.org>
Envoyé: Vendredi 23 Avril 2021 22:41:03
Objet: [SIGCIS-Members] whirlwind, radar and real-time tracking

Greetings Colleagues,
   I've been working on restoring a 1951 Whirlwind program, written at 
MIT, used to demonstrate real-time tracking of aircraft with radar for 
the purposes of guiding an interception (the Cold War was in full flight 
in the 1950's).  This work ultimately led to the massive SAGE air 
defense network in the US.
   You can see some rather informal preliminary notes on the work at
   The program does work in simulation; you can see a four-minute video 
of the simulator running an intercept at
   Spoiler alerts: The original really did display moving dots on a CRT, 
but the graphics are "spartan" to say the least.  And nothing in 
particular happens when the intercept actually happens.

   Would anyone know of contemporaneous work involving digital computers 
for either radar tracking or real-time computing around 1951?  I think 
all the familiar digital computers from those years were used in 
applications where batch operation was perfectly acceptable, e.g., 
computing ballistics tables.
   Innovations like this rarely occur in a complete vacuum, but I don't 
see references to any similar digital computing projects.
   If anyone has pointers, do let me know!
Guy Fedorkow

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