EDSAC

EDSAC, short for Electronic Delay Storage Automatic Calculator, was an early British computer built at the University of Cambridge's Mathematical Laboratory. Designed under Maurice Wilkes and his team, it was completed in 1949 and became one of the first stored-program electronic computers to be placed into service. It demonstrated the practicality of storing programs in electronic memory and performing long-running calculations in science and engineering.

Technology and architecture: EDSAC used mercury delay-line memory to store 1024 words of 18 bits each. The processor was accumulator-based, featuring an instruction set with operations for arithmetic, data movement, memory reference, and conditional jumps. Programs were loaded from paper tape and output was produced on a teleprinter or printer, enabling longer and more complex computations than earlier machines permitted.

Operation and programming: The machine ran a relatively simple, low-level programming model compared with later systems, but it introduced important software concepts such as subroutines and library routines that influenced later Cambridge projects. Its work included numerical analysis and other scientific computations, contributing to the early practice of software development as a discipline.

Legacy: EDSAC helped establish the feasibility and value of stored-program machines in the United Kingdom and influenced subsequent Cambridge computers, including the later EDSAC 2. It played a key role in the emergence of computer science as an academic field at Cambridge and contributed to the broader adoption of programmable electronic computing in the postwar era.