What is EDVAC?
EDVAC (Electronic Discrete Variable Automatic Computer) was one of the earliest electronic, stored-program computers developed in the 1940s. It marked a revolutionary shift in computing history by utilizing binary code instead of decimal numbers and storing instructions directly within its memory.
Key Takeaways
Developed by the University of Pennsylvania as a successor to ENIAC.
Introduced the practical implementation of the Von Neumann architecture.
Pioneered the use of binary numbering systems in electronic computing.
Replaced manual, physical rewiring with internal stored programs.
History and Evolution
EDVAC was conceived during the construction of ENIAC to address its major limitations. Designers J. Presper Eckert and John Mauchly, along with mathematician John von Neumann, revolutionized the design by proposing a computer that could store both data and program instructions in memory. Construction began in 1946, and the machine was fully operational at the U.S. Army Ballistic Research Laboratory in 1951, running reliably until 1961.
How EDVAC Works
Unlike its predecessor, which required physical plugboards to change tasks, EDVAC operated through an internal electronic memory system. It read instructions sequentially from its memory, executed them via its control unit, and processed calculations using binary logic. The architectural blueprint established by this machine remains the fundamental design for modern computers.
Key Technical Specifications
Logic System: Binary serial architecture
Memory Technology: Acoustic mercury delay lines
Memory Capacity: 1,024 words of 44 bits each
Physical Components: Approximately 4,000 vacuum tubes and 10,000 crystal diodes
Power Consumption: 56 kilowatts of electricity
Weight and Size: Roughly 7,800 kilograms, occupying nearly 50 square meters
EDVAC vs ENIAC
| Feature | ENIAC | EDVAC |
|---|---|---|
| Number System | Decimal | Binary |
| Programming | Physical rewiring and switches | Stored program memory |
| Memory Type | Vacuum tube accumulators | Mercury delay lines |
| Tube Count | Around 18,000 vacuum tubes | Around 4,000 vacuum tubes |
Advantages and Limitations
Advantages
Stored Program Concept: Enabled swift switching between different computational tasks.
Efficient Design: Binary logic significantly reduced the number of vacuum tubes required.
Increased Reliability: Fewer tubes meant less heat generation and lower hardware failure rates.
Limitations
Physical Footprint: Required massive, specialized rooms and heavy power infrastructure.
Maintenance Demands: Vacuum tubes still burned out frequently, requiring daily upkeep.
Serial Processing: Operations were executed one bit at a time, limiting processing speed.
Related Technology Terms
ENIAC: Electronic Numerical Integrator and Computer
Von Neumann Architecture: A computer design framework utilizing a shared memory space.
Vacuum Tube: An early electronic component used to control electrical current.
Mercury Delay Line: An early form of reliable computer memory using sound waves.