How do Computers Work?

Diana Bocco

Computers get things done as a result of a combination of hardware, software, input, and output. The CPU, or central processing unit, is where most of the heavy lifting occurs. While the technical aspects of what makes computers work could be difficult for a non-professional to understand, the mechanical aspects of it can give you a clear idea of what and how things happen inside.

A computer's power supply is important to make sure the computer gets the electricity it needs to run.
A computer's power supply is important to make sure the computer gets the electricity it needs to run.

Computers work thanks to a series of hardware devices that are closely interconnected. When looking at a computer from the outside, the basic parts are the system case, which may be a tower for a desktop machine or the body of a laptop; the monitor; and the keyboard. A mouse or trackpad may or may not be essential to the functioning of a computer, depending on the type and model. Many computers also have a CD or other disc drive in the case.

A graphics card is what allows graphics to display on a computer.
A graphics card is what allows graphics to display on a computer.

Most of the essential things that make computers work are inside the case, away from your eyes. The motherboard is central point of the computer, where all the various components attach and communicate with each other. Key to allowing a computer to work is the central processing unit (CPU), the central stop for all the processes the computer goes through. As a command is sent, such as "open a program" or "turn the monitor on," the CPU interprets this order and then acts accordingly.

A flash drive, a type of computer drive that's used to store data.
A flash drive, a type of computer drive that's used to store data.

Once the computer is turned on, or booted up, the CPU goes on to activate certain sections so that it can then give you access to programs and processes. Computers operate based on the CPU granting access to users, so if the booting up process malfunctions, it can mean that the computer cannot be used, even if everything else inside is working properly.

A computer motherboard.
A computer motherboard.

Memory is also extremely important to allow a computer to work. The two main kinds of memory are Random Access Memory (RAM) and Read-Only Memory (ROM). ROM is stored data, and cannot be written to; RAM is memory that can be read from and written to, allowing new data to be saved. In many cases, additional RAM can be added.

A dual core CPU mounted to a motherboard.
A dual core CPU mounted to a motherboard.

One kind of ROM is the Basic Input/Output System (BIOS), which is in charge of communications between the software on a computer and the hardware. When a computer is first turned on, the BIOS checks basic data such as hard memory, RAM, any cards installed, and other devices. BIOS also checks for booting up errors and offers to fix them if necessary.

A computer mouse.
A computer mouse.

Other less central — but no less vital — parts that let computers work include the power supply, transformer, and battery. These parts make sure each component gets the electricity it needs in the proper amount, and that key information is saved even when the power is off. The computer drives, including hard drives, flash drives, and any drives with removable media, such as CD-ROM drives, allow the user to upload new data and applications to the computer and save files. The cooling system helps keep all of the components from overheating.

A screenshot of a BIOS configuration screen.
A screenshot of a BIOS configuration screen.

Most computers also have other components without which a computer would be more difficult to use. Graphics cards allow the computer to display graphics on the monitor, and come in many different levels. Sounds cards allow the computer to play sounds. Connecting to the Internet or other computers requires a modem. Most computers come with all of these components, and often it is possible for the owner to upgrade each to newer or more advanced versions.

A laptop.
A laptop.

Input/output (I/O) is the name given to the processes or components needed to interact with the CPU and make computers work. These include the monitor and keyboard, but also CD-ROMs and removable flash memory cards. Input/output processes allow you to order the computer to do something, making the essential for interaction and use.

A desktop PC.
A desktop PC.
CD-ROM drives allow users to upload new data to the computer.
CD-ROM drives allow users to upload new data to the computer.
A cooling pad may help keep a laptop from overheating during certain tasks, like playing video games.
A cooling pad may help keep a laptop from overheating during certain tasks, like playing video games.
Installing additional RAM may help increase computer speed.
Installing additional RAM may help increase computer speed.
Computer monitors display the programs being used.
Computer monitors display the programs being used.
A computer's hard drive stores much of its data.
A computer's hard drive stores much of its data.
Various computer drives allow users to save information or files.
Various computer drives allow users to save information or files.

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Discussion Comments

anon950754

People should learn different numeral systems, like binary.

It uses two digits: 1 and 0, and each place is that of a power of two.

So, in 1000, a 1 is in the 8's place, because 2^3 is 8. In 1, a 1 is in the ones place because 2^0 is 1.

anon341354

From my understanding, think of it like this. The code is like a program and with each one sent, it sends back a program that it is meant to do. Like, when you press these letters on the keyboard it sends a code and with that code it transfers it to a processor. So, when you press the letter A, it sends the code (100111001) and it processes it in the core into the letter A on the screen. I understand it all mathematically but I don't understand how it creates codes using electricity because it boosts it there and decreases it there. How does it create a code?

anon134424

Its all 1's and 0's. think of a computer as a bunch of on/off switches. Letter A being represented by the binary code: 01000001. And so on. Every click button, every keystroke, every function (action or reaction) is represented by a code.

The computer then interprets the standardized code representation into an action/reaction, outputting and/or inputting resulting code. Images, movies, etc are simply just pixels of color, each pixel mapped to a coordinate on the monitor, each coordinate represented by a binary code. Each color mapped as well. I'd suggest that if you want to start your understanding from the very bottom up, start reading about state machines, boolean algebra, Finite automotons. Move on to binary algebra/math. Move onto assembly then some research on operating systems and how they work.

All OS's are attempting to do the same thing regardless as to who makes them (OSX, Unix, Windows). It's a very complex subject, which cannot be completely answered. it must be studied to fully understand. Hope this helps!

anon122877

At 52 I am enrolled in local tech. college taking computer information systems. I am looking for a graphical illustration on the process from keyboard to monitor, the path through memory to processor to busses etc. After 28 years building custom cabinets I need all the help I can get. Thanks if anyone can help.

anon114778

People, I'm afraid its just not that simple. you can't simply learn how computing and networking work that easily. it can take a lifetime of education and you won't have even hit the tip of the iceberg.

'how computers work' just isn't a good question. it's too broad because there are so many components and services and underlying protocols that you have to just concentrate on one area and start learning from there. simply knowing how a web page appears on your screen after typing it's 'address' in the url bar is complicated in itself, never mind 'how computers work'. start somewhere specific and broaden your knowledge.

anon108421

the questions I see here don't appear to be those from people in contact with computers. I mean to the computers themselves. the people seem much of an application layer bunch. No offense! I was like that once. My experience based advice: get closer to the discipline. Time will take care of the rest!

anon86211

My problem is what are computer classifications and components of computer, hardware, software and applications of computers and memory.

anon74962

The answer is many layers of abstraction or in laymen terms, they are unable to explain it or plain don't really know themselves. I sure don't!

anon44095

You need the write book on the subject. There must be one somewhere.

anon40293

This is a poor description. Its like saying a car works by a motor turning its wheels and which then causes it to move. Without ever bothering to explain how internal combustion works.

anon39995

can someone explain the relationship between computers and numbering systems? Thanks!

anon30675

I agree. That's what I'm trying to figure out.

How does me pressing a button turn into a series of images on the computer screen?! What's going on in the processor itself?

reenpeery

okay, i understand totally that there is input and there is output. that makes total sense. What is confusing to me is what actually takes place in the processor? I ask people how computers work and nobody seems to be able to tell me how the computer goes from simple binary code (100111001) to me being able to play Grand Theft Auto IV on my tv. How do series of numbers become usable visual tools? baffles me

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