Computer systems

What is a computer? – Computer systems

A computer system is a nominally complete computer that includes the core hardware,* peripheral equipment, the operating system and the application software* needed and used for full operation. In a broader sense, the term 'computer system' may also refer to a computer network* which is a group of computers that are linked and function together in order that the interconnected computers, as well as their users, can communicate and cooperate with each other effectively and efficiently to achieve a certain goal.

Typical examples of computer networks are

computer network; computer clusters; grid computing; Internet; cloud computing

Hardware and software

A computer is a rather complex system of physical and intangible components including
– the hardware* configuration, i.e. the physical structure of the computer system which determines how the "core" hardware (including the central unit, the motherboard etc.) and the peripheral devices can communicate with each other, and
– the software* system, which controls the hardware and produces a desired behaviour from the computer.
We can draw a clear distinction between the main software (i.e. the operating system) which allocates and controls the system resources, and the set of application software products, which enable the computer to perform different tasks.

We often speak about computer architecture which refers to the specification of a computer system at a somewhat general level, including the description of the hardware configuration and the main software components (i.e. the constituent parts of the operating system). A given computer architecture usually has several implementations which, in time, can lead to a family of computers which may have backward* and/or upward* compatibility with each other. (A famous and successful example was the x86 architecture including e.g. the Windows XP and the Windows 7 operating systems.)

hardware; software; Windows; various Windows versions

Abstract models of the computer

To describe a computer as a system, we have two abstract models.

The black box model of the computer as a data processing machine can be illustrated as follows:
A számítógép mint fekete doboz

Note that the terms 'data' and 'information' are often used more or less synonymously. Nevertheless, we can make a clear distinction: on the one hand, data* usually refers to stored information; on the other hand, information* can be considered as retrieved data to be used up for something useful (e.g. it can be an input for further processing).

The black box model has several applications. The term 'black box' can be efficiently used to refer to a wide range of open systems including a transistor, a logic circuit, a computer, an algorithm, an automaton, a neural network, or even the human brain.

Boda István, 2024.