The M9 View

The M9 From A Bell Labs View
Because of a general embargo on the publication of defense-related technical information during WWII, there was a great deal of work that came to light quite some time after the original development. Many M9 project details on its various components fell into this category, which included op amp diagrams.
Nonetheless, Bell Labs did begin documenting some of the M9 work, even before the war ended. In the Bell Laboratories Record of December 1943, there was published a tribute to Harold Black, for his work on the feedback amplifier (Reference 31: Recognition of Harold Black, "Historic Firsts: The Negative Feedback Amplifier," Bell Laboratories Record, Vol. 22, No.4, December, 1943, pp. 173. (A Bell Laboratories tribute to the Black negative feedback amplifier invention)). In the same and subsequent issues, there were published two stories on a public demonstration of the M9 system, as well as its development (Reference 32: "Electrical Gun Director Demonstrated," Bell Laboratories Record, Vol. 22, No. 4, December 1943, pages 157-167. See also: "Development of the Electrical Director," Bell Laboratories Record, Vol. 22, No. 5, January 1944, pages 225-230. (Bell Laboratories narratives of the M9 gun director system demonstration and development)).
Several key developments in electrical components were also documented in the Bell Laboratories Record, on capacitors, resistor networks, resistors, and precision potentiometers (References 33: J. R. Weeks, "Polystyrene Capacitors," Bell Laboratories Record, 24, March, 1946, pp. 111-115. (Development of a new capacitor film dielectric for electronic analog computer networks), References 34: E. C. Hageman, "Precision Resistance Networks for Computer Circuits," Bell Laboratories Record, 24, December, 1946, pp. 445-449. (Development of precision resistor networks for electronic analog computers), References 35: C. Pfister, "Precision Carbon Resistor ," Bell Laboratories Record, 26, October, 1946, pp. 401-406. (Development of deposited carbon resistors for electronic analog computers), References 36: D. G. Blattner, "Precision Potentiometers for Analog Computers," Bell Laboratories Record, 32, May, 1954, pp. 171-177. (Development of precision wire wound potentiometers for use in electronic analog computers)).
There was also a fitting recognition of M9 designers Lovell, Parkinson and Kuhn within the Bell Laboratories Record, on the occasion of their Medal for Merit award in April of 1947 (Reference 37: Recognition of M9 Designers C. A. Lovell, D. B. Parkinson, and J. J. Kuhn, "Medals for Merit," Bell Laboratories Record, Vol. 27, May, 1947, pp. 208. (The Medal for Merit awarded to the M9 designers on April 8, 1947 is the nation's highest civilian award)). The importance of this work in the view of Bell labs is underscored by some of the distinguished names associated with the project. Contributors beyond those mentioned above also included Hendrick Bode, Claude Shannon, and other notables of the Bell Labs staff. Finally, there was a then-unrecognized importance. It established the utility of the (yet-to-be-named) op amp concept— op amps were born!
The M9 From A World View
Viewed historically, the work of Lovell, Parkinson and other Bell Labs designers assumes broad significance, since it was war-needs driven, and the outcome literally affected millions of lives. The work provided an analog control computer for a gun director system instrumental to the war effort, achieving high hit rates against incoming targets— up to 90% by some accounts. The work of the M9 system teamed with the SCR584 radar system was highly successful at its mission— indeed fortunate for world freedom.
Robert Buderi wrote a detailed narrative of WWII radar developments, and his book contains an interesting account of the M9's role (Reference 38: Robert Buderi, The Invention That Changed the World, Simon and Schuster, 1996, ISBN: 0-684-81021-2. (A marvelous account of radar development during WWII, centered largely on the MIT Radiation Lab team— includes a narrative on the integration of the M9 fire control system with the SCR-584 radar, and the system's operational success)). A broad, singlesource computing, control, and historical perspective is found in David Mindell's thesis, "Datum for its Own Annihilation:" Feedback, Control and Computing, 1916-1945, (Reference 39: David A. Mindell, "Datum for its Own Annihilation:" Feedback, Control and Computing 1916-1945, PhD thesis, MIT, May 2, 1996. (Historical survey of computing control systems. Chapter 8 of this work is 'Radar and System Integration', which covers the Bell Labs work on the T10 and M9 gun director projects)).
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