You have to follow the instructions of a user of an information programme.

There are quite a few applications, for example, video games are like instructions.

It is the logic that the computer has.

The computer writes a set of instructions.

When we use a programme, the computer follows the programme's instructions.

The operating system (OS)

There is one OS per computer; no more, no less.

The OS defines the internal logic of how the computer works.

To program the OS, we need to know the hardware components and how

they are connected.

For example, when we want to shut down the computer, the OS tells it whether to shut down or not.

The operating system was programmed solely to manage those hardware components.

In those days, the operating system was stored on a floppy disk, which was loaded after turning on the

computer.

The user could then start using the application.

It has a graphical display, so we can interact with the computer using a mouse.

It can connect to the Internet.

Today, the most common operating systems are those marketed by Microsoft: Windows Vista, Windows 7...

Microsoft Windows has a long history that began with the operating system called ‘DOS’ (Disc Operating System).

For example, computer keyboards. Another example is Wi-Fi, which you cannot touch, so it is not hardware.

The most basic components are the CPU, memory, graphics card, and peripherals.

The CPU (central processing unit): This is a green board

with chips and other electronic components.

It is also called the processor and is the brain of the computer.

Memory: Stores information.

Fixed memory: This normally remains inside the computer.

1. Hard drive: This is a set of rigid discs

with a magnetic surface.

It stores all your programmes and files.

Advantages: It stores around 1 TB of data. We can save and delete information whenever we want.

Disadvantages: It is relatively slow, taking longer to read and write information.

2. RAM (random access memory): This is a green card with chips.

It is installed in a slot on the motherboard.

More can be added if desired.

RAM stores the applications and files we are

using.

Advantages: It stores (writes) and retrieves (reads) quickly.

Disadvantages: We lose our work if there is a power cut.

Memory capacity is smaller (around 6 GB) than that of a hard drive.

Portable memory devices: Easy to connect and disconnect from a computer and can be transported.

CDs and DVDs (‘optical memory devices’) use light to function.

Advantages: Inexpensive.

Disadvantages: Not good for rewriting.

USB memory sticks and memory cards: Store information

on chips.

Advantages: They can be rewritten and are fast.

Disadvantage: They are more expensive than a CD or DVD.

Graphics card

The graphics card is similar to RAM.

It defines the format of the graphics and helps to process them more quickly.

They are used for video games, watching films and graphic design.

Peripherals: Elements of communication between the computer and the outside world.

Input peripherals provide information to the

computer: Keyboard, mouse, microphone,

thermostat...

Output peripherals: The computer uses them to provide information to us or to an actuator: screen, speakers, printer, light bulb, motor...

A peripheral can be both input and output;

an example is a router for connecting to the Internet.

The router receives information from the Internet

and sends information to the Internet.