| ACE computer | |
|---|---|
| Name | ACE |
| Developer | National Physical Laboratory |
| Designer | Alan Turing, James H. Wilkinson, Harry Huskey |
| Manufacturer | English Electric Company |
| Generation | First-generation computer |
| Released | 1950 |
| Predecessor | Pilot ACE |
| Successor | DEUCE |
| Units sold | Approximately 30 |
ACE computer. The Automatic Computing Engine (ACE) was a pioneering early electronic stored-program computer developed in Post-war Britain. Its design, fundamentally influenced by the theoretical work of Alan Turing, was realized at the National Physical Laboratory (NPL) under the leadership of James H. Wilkinson. The machine's innovative architecture, emphasizing high-speed processing through extensive use of Delay-line memory, established important precedents for later commercial computers like the English Electric DEUCE and influenced computing concepts internationally.
The project originated from Turing's seminal 1945 report, "Proposals for Development of an Automatic Computing Engine," written after his wartime experience at Bletchley Park. Frustrated by bureaucratic delays at the NPL, Turing departed for the University of Cambridge in 1947. Development was subsequently spearheaded by James H. Wilkinson, with crucial contributions from visiting American engineer Harry Huskey. A smaller, proof-of-concept version called the Pilot ACE was completed and ran its first program in May 1950, successfully demonstrating the design's viability. The full-scale ACE computer became operational in 1958, built by the English Electric Company. The project faced significant challenges, including management conflicts with the NPL's director, Sir Charles Darwin, and competition from contemporaneous machines like the Manchester Mark 1 and the EDSAC at Cambridge.
The ACE design was notable for its asynchronous operation and a revolutionary emphasis on a minimal instruction set to maximize speed, a concept later known as RISC. Its central processing logic was built using approximately 800 Vacuum tubes. The primary memory system employed Mercury delay lines, a technology also used in the EDVAC and UNIVAC I, which stored data as acoustic pulses. A key innovation was the extensive use of Optimal programming and the "best delay" principle, where instructions were timed to emerge from the delay lines precisely when needed, minimizing idle processor cycles. This complex memory organization required sophisticated control circuits, but enabled remarkably efficient operation for its era.
Programming the ACE was a highly specialized task, demanding deep knowledge of its physical architecture. Programmers, including early figures like Donald Davies, had to manually optimize the placement of instructions and data within the delay lines to minimize latency, a process akin to Assembly language scheduling. The machine used a pure Machine code with instructions for arithmetic, logical operations, and branching. Despite the complexity, a substantial library of Subroutines was developed for mathematical and scientific computations. This hands-on programming environment fostered advanced techniques in Numerical analysis, directly contributing to the field of Computational science.
The ACE and particularly the Pilot ACE had an immediate and substantial impact. The Pilot ACE was used for vital post-war research, including aeronautical calculations for the Royal Aircraft Establishment and work on Gravity waves. Its design was commercialized by the English Electric Company as the DEUCE, one of the most successful early British computers, with installations at institutions like the Aircraft Research Association and Lloyd's of London. The ACE project trained a generation of influential computer pioneers, such as Donald Davies, later a key figure in Packet switching. Turing's original ACE report is considered a foundational text in Computer architecture, presaging concepts like Microprogramming and Cache memory.
The full ACE computer operated at a clock rate of 1 MHz. Its Delay-line memory provided a main store of 200 words, with additional longer delay lines offering slower secondary storage. The word length was 32 Bits, plus a timing bit. The machine's Arithmetic logic unit could perform addition in about 64 Microseconds and multiplication in approximately 2 Milliseconds. Input and output were handled via Punched card readers and Punched tape equipment, standard for the era. The physical machine consumed significant power and required dedicated cooling systems for its vacuum tube components.
Category:Early computers Category:Computer-related introductions in 1950 Category:National Physical Laboratory (United Kingdom)