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Definition of a Computer

In this step, you are going to look at what is meant by the term computer, and try to come up with a definition for what a computer actually is. What Does Computer Mean? It often surprises people that the term computer predates the discovery of electricity generation. Originally, it was a term that applied to humans. These people would carry out hundreds of laborious mathematical calculations, obeying very strict rules to obtain answers. Teams of human computers - usually women - would work on a task, allowing calculations to be conducted in parallel.

In this step, you are going to look at what is meant by the term computer, and try to come up with a definition for what a computer actually is.

What Does Computer Mean?

It often surprises people that the term computer predates the discovery of electricity generation. Originally, it was a term that applied to humans. These people would carry out hundreds of laborious mathematical calculations, obeying very strict rules to obtain answers. Teams of human computers – usually women – would work on a task, allowing calculations to be conducted in parallel.

An image circa 1940 of six women in an office working out calculations using paper and pens.

NASA

In 1935, NASA’s Langley Memorial Aeronautical Laboratory set up its first “Computer Pool”. Until the 1970s, the human computers at Langley calculated data from tests in wind tunnels and played an integral role in both aeronautical and aerospace research. Virginia Tucker was one of the first members of the “Computing Pool” and went on to train over 400 women across the aeronautical laboratory.

Modern Computers

The modern computer doesn’t differ much from the early human computers, with regard to its basic function. They still do little more than carry out laborious calculations. However, with the advent of modern electronics, these machines can now perform billions of calculations every second. This ability to perform calculations at such an incredible speed means that, given the correct set of instructions, computers can perform an unbelievable range of highly complex tasks.

Computers Everywhere

Modern computers are almost ubiquitous, and the number of places that computers can be found is surprising. You may recognise that our desktops and laptops are computers, and most people would identify that their phones, tablets, and games consoles are also computers. However, computers are in some of the most mundane objects in our lives. Our microwaves, our traffic lights, our childrens’ toys all can contain computers. Cory Doctorow summarised it pretty well in his keynote speech at the Chaos Computer Congress, titled The Coming War On General Computation:

There are no airplanes, only computers that fly. There are no cars, only computers you sit in. There are no hearing aids, only computers you put in your ears.
With computers being so integral to our daily lives and performing such a wide range of extremely complex tasks, it is easy to either overlook them completely or regard them as such complicated and unfathomable devices that they are impossible for a layperson to even begin to comprehend. Hopefully, as your learning develops, you will begin to understand what a computer actually is, and have some understanding of how they work. If at any time you find the concepts a little overwhelming, it can help to keep this quote in mind:

Computer – A Definition

A general-purpose computer is one that, given the appropriate instructions and required time, should be able to perform most common computing tasks.

This sets a general-purpose computer aside from a special-purpose computer, such as the one you might find in your dishwasher, which may have its instructions hardwired or coded into it. Special-purpose computers only perform a single set of tasks according to prewritten instructions. From now on, you can take the term computer to mean a general-purpose computer.

Input-Process-Output

Using a simplified model, a computer can be discussed in terms of inputs, processes, and outputs, which are summarised in the diagram.

A diagram of four boxes labelled "Input", "Process", "Output", and "Storage". Arrows point from "Input" to "Process", "Process" to "Output", and "Output" to "Input". In addition, arrows indicate the two-way transfer between "Process" and "Storage", and back again.

A computer will receive data via a variety of input methods. This could be in many forms, such as a human typing on a keyboard, a sensor reading the temperature, or data coming in via the internet. The computer will then process this data. This is just another way of saying that it will perform calculations using the data, according to the instructions that it follows. It can store the data if given the instruction to do so, and it can also read previously stored data. Then, the computer can output the result of its calculations. This could be by displaying it on a screen, by writing the new data to a file, sounding an alarm, or updating a web page, as just a few examples. Often, the processed data is also fed back into the computer to act as new input.

Although the input, output, and storage parts of a computer are very important, they will not be the focus here. Instead, you are going to learn about the process part, focusing on how the computer is able to follow instructions to make calculations.

Think about examples of specialist and general-purpose computers, and consider their inputs, processes, and outputs. What classroom activities do you think you could develop, to help learners understand what a general-purpose computer is?

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How Computers Work: Demystifying Computation

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