Timeline of Computer Development

The technological advances in micro electronics have helped the rapid expansion of computers into our daily lives. From the early beginnings of huge machines that could fill whole buildings and weigh in at 30 tonnes, to the slimline personal laptop computer of today that weighs a few grammes and can fit in a small bag, the evolution of the machines has been rapid.

The early computers were invented to perform specific functions – the Colossus to break codes by performing thousands of calculations through trial and error much quicker than a human could do, the WITCH to perform thousands of calculations with perfect reliability to help with the design of a Nuclear Power Plant. Initially, most computers where built for specific functions such as these and their programmability was limited. Due to the components being used they required lots of space and generated huge amounts of noise and heat. The earliest machines used valves – large glass tubes that could be on or off. Input and output tended to be on thin paper tape which then needed to be interpreted separately into any readable data.

In the 1950s and 60s big business started to see that computers could help them keep track of the vast amounts of data they were generating – customer orders, stock details, payroll information etc. and that they should not just be the preserve of scientists.


By the 1960s valves were being replaced by smaller and much lower powered transistors. This helped the size and cost of computers to reduce. Along with advances in programming medium sized businesses could now make use of the computer in their own operations. Data storage was still quite low as numbers do not take much space – not like the high amounts of data required to store images and film in today's computers.

With the continuing development of the transistor, and then the circuit board and microprocessor in the 1970s, the size of computer components got smaller and smaller. This brought costs down and opened up a whole new market to the computer producers. Now small businesses and personal users wanted to be able to use computers. Suddenly schools, universities and people's homes had computers. Leaps in processing, such as the ARM processor, had unexpected benefits in opening up whole new mobile markets thanks to their incredibly low power consumption levels.

As personal use grew so too did the processing power required to run ever increasingly complex programmes. Use of graphics and sound increased and the need to be ever more mobile. Processors increased in speed and complexity, RAM increased exponentially as did the amount of storage needed. Yet as these sizes increased, the components themselves got smaller!

Today we can hold on a single, 5cm long, pen drive thousands of times the amount of data that would have been held on a single, one metre diameter, hard drive from the 1960s!