Data organization

Organizations have always had to save and process different data for their operation. Data organization for its subsequent analysis has been one of the priorities for the organizations. Many years ago, computers were not available yet, the data was recorded on paper and stored in filing cabinets. Physical cabinets with drawers, which we consulted when we needed to recover any of these data.

This data organization forced us to have large spaces for storage and required a great effort of registration. It also had many other drawbacks. Always we wanted to access a piece of data, it spent considerable time locating it. Access was exclusive so that if someone was consulting any file of information, it was not available to anyone else. All this without mentioning the limited possibilities available for data processing.

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The power supply

All the devices connected to the motherboard, need to be supplied with the electrical current for their operation. The power supply is the component of the computer that fulfils this function.

We take the electrical current from the electric supply network, to which we plug the PC Power Supply, which transforms alternating current into direct current, at suitable voltages for the computer devices. Therefore, although we normally refer to the Power Supply with that name, it does not generate electricity, it is not a source, but a transformer from alternating current to direct current, and from high voltage to low voltage.

Usually, a computer needs a 12-volt direct current to power the motors of devices, such as hard drives, and a 5-volt or 3.3-volt direct current for the different electronic components.

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The motherboard

When we open a computer and look inside, it is inevitable to be surprised by the motherboard. The amount and variety of components can scare us a little, but in this post, we are going to analyze them and take away some basic ideas that will help us in our understanding of motherboards. In any event, first thing is to understand what the motherboard is and what it is for.

The motherboard
The motherboard

The motherboard is the integrated circuit that connects all the components of the computer. Some of them will be directly soldered to the plate. Others, such as the CPU or RAM, are connected through dedicated connectors. And the rest they do it through the so-called expansion buses (internal ports) or through the external ports.

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Components of the computer

In previous posts, I have given a small introduction about the computer and its evolution, as a general purpose machine, and some basic brushstrokes about its architecture. The next posts will deal in detail with the different components of the computer, but before that, I think it will help to make a small list with these components, so that the student can get an idea of what is to come.

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The architecture of computers

Talking about the architecture of computers, we refer to the set of all the blocks (one or several components) and the communications between them, which make the computer work in a coordinated way, serving a common purpose. Each block fulfills one or more tasks, which orderly and coordinated contribution makes the computer fulfills the function for which it was designed.

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Classifying computers

We have a natural tendency to pigeonhole and classify things, and computers are not an exception. In this post, we are going to see the most common way of Classifying computers.

If we wonder what type of computer our laptop is, you might think that it fits perfectly into the category of minicomputer however it isn´t, it is really a microcomputer. But how important is this for me? What matters if my laptop is a minicomputer or a microcomputer? Well, even if you are never going to work with another computer than your laptop, it is always good to know that there are other categories of computers with other features, many more than those of your laptop. Who knows, maybe on some occasion you will have to face some task too big for your laptop.

The most common way to classify computers is according to their performance. We distinguish 5 types or categories.

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Control Structures in Java

The control structures in java will be used to modify the sequential flow of a program. That is, the order in which the instructions on it are executed.

In a program, instructions are executed from top to bottom, and from left to right, depending on the order in which they appear. The different instruction blocks of our program will follow this sequential flow to execute the instructions. The instruction blocks shall be delimited by braces brackets:

Block {
instruction 1;
instruction 2; instruction 3;
instruction 4;

However, in some cases we will need to break this sequential flow. Reasons for that can be many, we may need to make a decision between one or several possible options, or maybe we need to perform some instructions several times. Therefore, we need certain structures that allow us to interrupt the sequential flow of the program, and move on to execute other blocks of code.

In this post, we will study the operation of the following control structures:

  • Decision making: if-then, if-then-else, switch.
  • Loop: for, while, do-while

Decision making structures

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Computer generations

A common way of showing the evolution of computers is to resort to the so-called generations, temporary periods of computer development. One generation begins with a disruptive technological advance and ends when another advance appears surpassing the first one and begging a new generation.

Traditionally there are 5 generations, although there are those who already speak of 6. I in principle continue speaking of 5 although I mention the technological advances that are already here and will surely end up closing the fifth generation and giving way to the sixth. These advances are Artificial Intelligence and parallel processing.

In my classes I use the slide below to introduce the generations of computers:

Computer generations
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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.