What Is A Computer?

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This question is technically very broad. Computers have existed ever since the first abacus was invented. A computer is anything that helps you compute, or perform mathematics. This definition has been vastly expanded in recent decades due to technological advances. At the core of it all, though, the definition is the same.

Computational Devices

I believe that if something helps you count, add, subtract, etc. then it can be considered a ‘computer’. Your fingers as a tool for instance, or an abacus, or a piece of paper and a pencil. Anything that ‘computes’ today, such as your cellphone, your PSP, your laptop, or your desktop tower, is built on this sole concept. The only difference between the two examples is that the latter use a particular technology to perform their calculations quickly and efficiently. This piece of technology is known as a processor.

Hardware vs. Software

Modern computers today, be it a laptop, a Nintendo DSi, a FlipVideo recorder, a PS3, or a TiVo, are all made up of what is known as hardware. Hardware refers to the physical electronics that make up any particular device. Because you can touch it, pick it up, etc. it’s ‘hard’. This is in contrast to what is known as software which refers to the data and instructions (programs) that ‘exist inside’ the devices (through electrical charges representing binary). It’s known as ‘soft’ because you can’t really ‘see’ it or pick it up physically.

The Processor; Without It You Got Nothing

As discussed there is one piece of hardware that a modern computing device can’t be without: the processor. A processor is a microchip (a piece of hardware made up of encased silicon that serves to map out a large amount of circuitry in a small space) that in essence processes all of the data (1’s and 0’s) brought to it by other pieces of hardware: the hard drive, and random access memory. It processes the data by ‘following instructions’ (chunks of binary data representing actions to be taken). These actions are able to be ‘followed’ by the processor because of the built-in circuitry. More about processors can be found in another article.

Where Data Comes From, What Happens To It, Where It Goes

As noted, a processor must have data (or software) to use, and this data normally comes from hard drives (or devices that act like hard drives such as disks), and random access memory (RAM). Other sources of data include read-only materials such as a DVD, or compact disc, a network connection (the internet), and the mouse and keyboard. Data ‘travels’ along the circuitry through constructions known as ‘busses’. Data that comes from ‘outside’ the processor is known as ‘input’. After the processor processes the data, the result is known as ‘output’ and is sent back down the bus towards its destination:


Data put into RAM is ‘forgotten’ or erased when a computer shuts down. RAM is purely for temporary storage for use by programs being executed (run) on the computer (by the processor). How RAM operates is constantly changing, but the last time I checked it generally used ‘refreshed’ electrical charges stuck in a sort of pseudo-limbo.

Hard drives are for storing more long term data, such as database records, or computer games, as the data won’t be erased between sessions. This is because hard drives (for the longest time) use a needle to write magnetic charges onto a rotating disc. Once the charge is written, the data stays until the charge is changed. Today there are some different types of hard drives, such as ‘flash memory’ drives which use microchips, and ‘solid state’ drives with no moving parts.

Seeing the Data

This is all fine and dandy, but it’s not very useful if we can never see the fruits of our work. Every successful computing device has some sort of display, typically today that is just a flat graphic display capable of displaying colored pixels. A computer will usually have some rudimentary graphics hardware under the total control of the processor in order to send data to a display or monitor, but most modern computers have whole processors dedicated to processing graphical data that work in tandem with the core processor of the computer. This is known as a GPU (graphics processing unit). Often the GPU even has its own RAM. These special processors will deal mostly with 3D computations to speed up graphical renderings, particularly useful for gaming and scientific modeling.

Putting It All Together

For the average user, and even programmer, that’s all you really need to worry about in terms of how a computer at the core works. Data comes into a computer through discs, a keyboard, network communication, and a mouse. This data is operated upon by a processor to create changes and results the user is looking for. That data is eventually displayed on the computer display device so that we as a user can appreciate it and find it useful.

You might think that looking at your computer screen, this can’t really be how a computer works. Just simple mathematical operations and processing of binary data really results in a beautiful display of windows, icons, 3D graphics, multiple running programs, etc.? Well, it’s true. The beauty about advancing technologies and computers is that over time basic operations become stable enough to build ever more complex software ‘on top’ of it. Processors become fast enough to do millions and billions of calculations a second, and memory becomes cheaper giving us larger ‘space’ to work in. To give you the user experience on your display, your computer is performing millions of basic calculations a second, shuffling data, moving it here and there. It really is amazing.

I hope you found this article helpful in understanding computers just a little more than you may have before.

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photo credit: gingerbread2011_19 via photopin (license)


I'm just a wunk, trying to enjoy life. I am a cofounder of http//originalpursuitssoc.com/ and I like computers, code, creativity, and friends.

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