With this post I start a serial with the main aim of explaining how a Personal Computer (PC) works and which are the most important features which have to be considered to buy a suitable PC for our needs.
Introduction
A computer is composed of several physical components, the hardware. The most important ones are the microprocessor, the memory and the motherboard (which controls the in/out devices and the memory and links them to the processor). The in/out devices are called peripherals. Examples of peripherals are the hard disk, the DVD unit, the graphic card, the sound card, the ethernet card, the modem and so on.
Introduction
A computer is composed of several physical components, the hardware. The most important ones are the microprocessor, the memory and the motherboard (which controls the in/out devices and the memory and links them to the processor). The in/out devices are called peripherals. Examples of peripherals are the hard disk, the DVD unit, the graphic card, the sound card, the ethernet card, the modem and so on.
Elements of a current Personal Computer: Case, Screen, Keyboard and mouseThe microprocessor is the brain of the system and executes the instructions loaded in the memory, the software. This memory, called RAM (Random Access Memory), is really fast but can't store any information if the computer is off. On the other side, a hard disk is a massive memory (much more than the RAM but much slower) which can store the information indefinitely.
Computers only understand binary information. This language only has two symbols: o and 1, called bits. 0 means no electrical signal at all. 1 means some electrical signal. With eight bits we create a "word", called a byte. Each word represents a letter, a symbol or a number. So, when we type an 'a' with the keyboard, eight bits are generated, stored in the memory and sent to the processor. The amount of information a memory can store is precisely measured in bytes or Megabytes (a megabyte is a million of bytes).
There is a kind of software quite important: The Operating System (OS). The OS is loaded in the RAM memory when the computer is turned on. The OS has to manage the peripherals and tells the processor what to do every moment and where the data it need is.
The data needed by the processor is introduced through an IN device, like a keyboard, a mouse, a hard disk, a DVD unit. The results are shown in an out device, like a screen, a speaker...
The microprocessor, the RAM memory and the peripherals are all connected to the motherboard, and all of them are linked each other through a BUS. Through the data bus the information travels from one device to another one. The address bus is used by the processor to tell the memory where the next instruction or data it needs is stored.
An exploded view of a modern personal computer and peripherals:1. Scanner, 2. CPU (Microprocessor), 3. Primary storage (RAM), 4. Expansion cards (graphics cards, etc), 5. Power supply, 6. Optical disc drive, 7. Secondary storage (Hard disk), 8. Motherboard, 9. Speakers, 10. Monitor, 11. System software, 12. Application software, 13. Keyboard, 14. Mouse, 15. External hard disk, 16. Printer
The components of a computer work syncronized by a clock. A clock tells each component when it has to send some information, when it has to get some information, when it has to process some information, when it has to show a result and so on. In short, the clock let the components talk and understand each other. A clock generates a lot of electrical impulses per second, and always the same number of impulses, so it has a frequency. The frequency is measured in Herz (Hz) or Megaherz (MHz). For example, if a clock generates a million of electrical impulses per second, it has a frequency of 1 MHz. The higher is the frequency, the faster the computer can work.
In the next post I will try to explain deeper the most important parts of a microprocessor and the features we have to consider to buy the processor more suitable for us.
