A computer is an electronic computer capable of performing a predetermined sequence of operations called a program. The very word "computer" comes from the English to compute ("calculate") and computer ("calculator"). Initially, a computer was called a person who performed arithmetic calculations. Moreover, in a number of cases he could use mechanical devices. Subsequently, the word "computer" began to call machines performing computational operations. These days, modern computers are capable of performing hundreds of different tasks, even indirectly not related to mathematics.
Computer classification
Modern computers, according to their purpose, are divided into several types, which in turn are subdivided into types:
I. Calculator
II. Console computer
III. Mini-computer
IV. Mainframe
V. Personal computer:
- desktop PC;
- notebook;
- subnotebook:
a) netbook
b) smartbook;
- the tablet
- game console
- PDA (pocket computer)
- communicator
- smartphone.
Vi. Work station
Vi. Server
Vii. Supercomputer
There are also specialized computers that only a limited number of people have access to: DNA computers, neurocomputers, biocomputers, molecular computers.
What a desktop computer is made of
The main part of any desktop stationary computer is the system unit. All other devices (monitor, mouse, keyboard, and so on) are connected to it. That is why sometimes the word "computer" does not mean the entire system, but only the system unit. In this case, the rest of the devices are called peripheral, as they only facilitate the execution of tasks. The "brain" of the system unit is the processor. It attaches to the motherboard. In addition to the processor, a network, sound and video card, RAM cards are inserted into the motherboard. The "motherboard" itself is equipped with controllers (modules for controlling peripheral devices). Inside the system unit is a power supply that supplies power to the boards. In addition, hard disks (hard drives) are located inside the case of the system unit, on which all information is stored, including the operating system. No system unit will work without installing cooling systems and an on / off control panel.
Input devices include primarily the keyboard and mouse. Until recently, a desktop computer could not be imagined without them. However, nowadays, touchscreen displays are widely used, on which information can be entered by pressing a finger on a virtual panel that opens on the screen.
Joysticks, webcams, microphones are also referred to as input devices
All listed input devices work at the request of a person. DVD-ROM or card reader reads information from external media, obeying the commands of the operating system. Sometimes they are separated into a separate subspecies, called drives of external data carriers.
Information output devices are a monitor and a printer. But if the first allows you to see dynamically changing information in a graphical form, then the second is able to display only static pages on paper. An important peripheral output device is the audio system (speakers or headphones).
There are also a number of devices that do not fit into the above classification: routers, modems, external hard drives, USB lamps and warming mugs, and hundreds of others.
