In the early days of computing, machines had fixed programs. This meant that the machine could only do one specific task. If you wanted the machine to perform a different task, you would have to physically re-wire and change its structure. This was a slow and difficult process.
The Change with Stored-Program Computers:
The stored-program computer was a major breakthrough because it allowed machines to store instructions (or programs) in their memory. This meant that a computer could easily switch between tasks simply by changing the program it was running, without needing to be physically altered.
The idea of stored programs was first proposed by Alan Turing in 1936. In 1945, Turing worked on developing the first electronic stored-program computer at the National Physical Laboratory. He also wrote a report called “Proposed Electronic Calculator,” which laid out the first specifications for such a computer. Around the same time, John von Neumann at the University of Pennsylvania also proposed a similar design for the EDVAC (Electronic Discrete Variable Automatic Computer).
The First Stored-Program Computer: Manchester Baby
The Manchester Baby was the first working stored-program computer. Built at the University of Manchester in England, it was designed by Frederic C. Williams, Tom Kilburn, and Geoff Tootill. On June 21, 1948, it successfully ran its first program.
The Baby was built to test a new type of computer storage called the Williams tube, which was the first device capable of storing digital information. Even though the Baby was small and considered primitive by later standards, it had all the key parts that modern electronic computers use.
The Development of Practical Stored-Program Computers:
Once the Manchester Baby proved that the stored-program concept worked, the next step was to make a practical computer. This led to the development of the Manchester Mark 1, which was a more advanced version of the Baby.
The Ferranti Mark 1, built by the Ferranti company, was the world’s first commercially available general-purpose computer. It was delivered to the University of Manchester in 1951, and several others were made in the following years.
The First Office Computer Job:
In 1947, a British catering company called J. Lyons & Company decided to get involved in the development of computers. They created the LEO I computer, based on the Cambridge EDSAC machine. This machine became operational in 1951 and ran the world’s first routine office computer job, marking a major step forward in the use of computers for business tasks.
In Summary:
- Early computers could only do one task and had to be physically rewired for new tasks.
- The stored-program computer allowed machines to store instructions in memory, making it more flexible and easier to reprogram.
- The Manchester Baby was the first stored-program computer and proved the concept.
- The Manchester Mark 1 and Ferranti Mark 1 became the first commercially available computers.
- The LEO I computer ran the world’s first office computer job in 1951.
The development of the stored-program computer was a key moment in the history of computing, allowing machines to become more versatile and widely used.