1. Computer architecture

In the 1940s, computers were built to carry out a single specific task. If you needed the computer to do a different job, you had to literally re-wire the computer by hand. This could take weeks.

Dr Von Neumann was a scientist who had an idea of how to create a computer that was far easier to change, and created what is now called the Von Neumann architecture. Its layout is shown below. It is made up of memory, control unit, arithmetic logic unit, input, output and buses.

The biggest change was the idea of interchangable 'software'. Program instructions are stored in temporary memory, along with the data that the program needs.

When you want to change what the computer is doing, you just change the contents of its memory to a new program.

This radically changed how computers are put together. Today, most computers use some variation of Von Neumann Architecture.