Inside A Computer

Looking Inside Computers

One of the defining inventions of the last century, the computer, has undergone a lot of transformations. The earliest models (sometimes referred to as “mainframes”) used in businesses used to be so large that they would take up an entire room.

mainframe computer

When you think of how far they have come in such a short period of time you can’t help but be amazed at the progress that has been made. Think of the computers now that can that fit onto circuit boards so small that they can be fitted inside watches and mobile phones that get ever smaller and thinner as they evolve.

The Core Components Of A Computer

No matter what the size, the essential parts to a computer have not really changed over the years. Internally, every computer has the same core parts: a CPU, memory, storage and pathways to connect the parts.


The CPU stands for Central Processing Unit and is really the brain of the computer. Without a CPU or with a faulty CPU the computer will not turn on. Just like a human brain, the CPU is perhaps the most complicated part of a computer and it controls everything. The CPU deals with the data or instructions by fetching it and then it processes the data / instructions.


There are two types of memory inside computers. ROM – read only memory and RAM – random access memory. ROM contains data that is permanently stored and is not lost when the computer is turned off. You cannot write to ROM, hence the name “read only”. RAM contains data that is temporarily stored while the computer is on and is used by software programs. Data can be written to RAM but the data in RAM is lost when the computer is turned off. Without the ROM your computer would not be able to start, or “boot up”.


Software programs and data files are stored inside your computer on hard disks which can be of different types – IDE or SATA. The capacity of hard disks has greatly increased over the years when the earliest disks only held about 5MB (megabytes) of data and now they can hold several TB (terabytes) of data. To help put that into perspective see below:

Computers work in bits (zeros and ones).

8 bits = 1 byte

1024 bytes = 1 kilobyte

1024 kilobytes = 1 megabyte

1024 megabytes = 1 gigabyte

1024 gigabytes = 1 terabyte


Buses is the name given to the pathways that connect all the components of a computer and via which instructions and data pass. The pathways could be in the form of electrical circuits and / or cables.


That was a very brief overview of some of the core parts inside computers. There are many other parts that are vital such as graphics cards which take the data and convert it into output suitable to display on an external screen. Every computer also needs “input devices” such as a keyboard, mouse and graphics tablets. Storage can be augmented externally through the use of external hard drives and USB memory sticks.

So you see there are many components and parts that all work together (and several that I haven’t even mentioned) to make our computers work. I am typing this post on a computer and you will be reading it on a computer whether it be a laptop, a desktop, a tablet device or a smartphone. Imagine what the next ten or twenty years will bring for advances in the computer world. It boggles the mind to think about the possibilities.



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