Electronic Discrete Variable Automatic Computer (EDVAC)

The Electronic Discrete Variable Automatic Computer (EDVAC) was one of the pioneering designs in the era of early electronic computers. It was a significant advancement over its predecessor, the Electronic Numerical Integrator and Computer (ENIAC), in that it was designed as a stored-program computer. This was a crucial innovation that laid the groundwork for future computer architectures.

Background

Work on the EDVAC began in August 1944 at the Moore School of Electrical Engineering at the University of Pennsylvania. The computer was part of the U.S. Army's Ballistic Research Laboratory initiatives during World War II, aiming to enhance the precision and efficiency of ballistic calculations.

Key Contributors

The primary architects of the EDVAC included John Mauchly and J. Presper Eckert, who were also instrumental in the development of the ENIAC. They proposed the construction of EDVAC in August 1945, with the project officially commencing in April 1946. John von Neumann also played a crucial role in the project as a consultant. His contributions were especially notable in the realm of logical design, which he summarized in his "First Draft of a Report on the EDVAC" in 1945.

Design and Architecture

Unlike the ENIAC, the EDVAC was designed to be a binary rather than decimal computer, marking a significant shift in computing methodology. It was a serial computer, meaning it processed one operation at a time in sequence. The design included automatic capabilities for addition, subtraction, multiplication, and programmed division, and it featured an automatic checking mechanism to ensure accuracy.

A notable technological feature of the EDVAC was its ultrasonic serial memory, which had a capacity of 1,024 44-bit words. This memory was based on delay line technology, which utilized the propagation of sound waves through a medium as a means of storage—a precursor to modern random-access memory (RAM).

Von Neumann Architecture

The conceptual foundation of the EDVAC's design was based on what is now known as the von Neumann architecture. This architectural model established that a computer's program and the data it processes should be stored in the same memory space. This was a revolutionary departure from earlier designs that required separate storage for instructions and data.

Impact and Legacy

The EDVAC represented a significant evolution in computing history, influencing subsequent computers such as the Electronic Delay Storage Automatic Calculator (EDSAC) and the Manchester Mark 1. It demonstrated the feasibility and advantages of the stored-program concept, which became the standard for computer architecture in the subsequent decades.