They follow instructions from the user and from the computer programmer.

Applications ( word processors, video games, etc..) are sets of instructions.

The hardware is the components that are interconnected. The computer needs all those components, but they are independent and we can change any of them.

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

The central processing unit is also called "the processor". It is the "brain" of the computer; it looks at the information and takes decisions based on logic.

It is the logic that the computers follows.

The programmer writes instructions. A set of instructions is a "program". When we use a program, the computer follows the instructions in the program.

Fixed memories:

They are normally stay inside the computer.

1.Hard disc: Also called "hard drive", it is a set of rigid discs with a magnetic surface. It stores all your programs and files

-Advantages: It can store a large amount of data, We can save and erase the information when we want.

-Disadvantages: It is relatively slow: compared to other types of memory, it takes longer to read and write information.

2.RAM: This is a green plastic card with chips. The RAM is installed in a slot on the mother board. Mother boards have empty slots so that we can add more RAM if we want. The RAM stores the applications and files that we are usings.

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

-Disadvantages: We lose the work if there is an electrical power cut. Small memory capacity compared to the hard disk.

Portable memories:

They are easy to connect and disconnect from the computer. Also thet are easy to carry. CDs, DVDs: We call them "optical memories" because they use light to work.

-Advantages: Cheap

-Disadvantages: Not good to rewrite.

Pen drives, memory cards: They store the information in chips.

-Advantages: Rewritable and quick.

-Disadvantages: More expensive than a CD or a DVD.

Entry peripherals:

Entry peripherals give information to the computer: keyboard, mouse, microphone, thermostat...

Exit peripherals:

The computer uses the exit peripherals to give information to us to an actuator: screen, speakers, printer, light bulb, motor...

A peripheral can be both entry and exit; an example is the router to connect to the internet. The router receives information from the internet and sends information to the internet.