What is a computer?

We all probably have an answer to the question: What is a computer? If you are reading this post, you are probably using one.

At the beginning of the program, I usually start the Computers Architecture course by asking my students this question. Even though the answers are very diverse, we usually reached the following consensus: “A computer is a programmable general-purpose machine”.

To properly understand it, you have to imagine the world with machines that perform only one task, as it was before the age of computers. For writing a document you have to use a typewriter, executing a mathematical calculation you use a calculator and for watching a video you use a video player connected to our television. Those were amazing times! Today, we use the computer for all these tasks and many more.

And programmable, because through programs we prepare the general-purpose machine to carry out a specific task of the many that it can perform. Continuing with the previous example, assuming we are on Windows, we would use Word to write one document, Excel to do the math, and Windows Media Player to watch the video.

With this brief discussion in class, I think a good starting point get established to get into the exciting world of computers.

If you want to know the architecture of these machines that we use today for everything, read the post computers architecture


This post is part of the collection “Computer Architecture” that reproduces the class notes that I use to teach the subject at ESIC. You can see the index of this collection here.