Basic IT concepts

and IT orientational training

with Tests for practice


  1. Basic IT concepts.
    • Topic map of the main concepts
    • Index of basic IT terms
    • Lexicon of basic IT terms
    • Tests for practice
  2. What is a computer?
    • Digital computer
      • What is a computer?
      • What does digital mean?
      • What are the most important data types?
    • Computer systems
      • What are the main components of a computer system?
      • What can be the benefit of using more than one computers at the same time?
      • In what forms can computers work together?
    • Computer hardware
      • What are the basic parts of the central unit of a modern computer?
      • What is the main function of the ALU and the CU?
      • What kind of peripheral devices do you know?
    • Early computers
      • What are the early computers meant for?
      • When were the ENIAC completed?
      • What lead to the Digital Revolution of our times?
    • Computer software
      • What is the main role of instructions in the computer?
      • What is software made up of, and what do programs consist of?
      • What is the function of the operating system?
    • Computer applications
      • What kind of special-purpose devices use computers as control systems?
      • Why can personal computers be considered as general-purpose devices?
      • What is the most important feature of the Internet?
    • Tests for practice

Recommended reading:
Computer Basics - Tutorial (2023-02-14)
Wikipedia (2023-02-08)

Useful tips for language learners

Here are some useful tips and activities to process the learning material:

Topic map of the main concepts

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Index of terms

Lexicon of basic IT terms


A digital computer is a digital electronic machine that can be programmed to carry out sequences of operations automatically.

Related terms

digital;* electronic;* program;* operation;*


machine, device; ≼instrument, tool, appliance, utensil; ≺equipment, apparatus;

carry out, perform (task, exercise, action, operation, instruction, program etc.); ≼ fulfil (task); conduct (exercise, operation); execute (instruction, program); run (program); ≺ do (task); take (action);


[adj+computer] digital ~; electronic ~;

[vt+computer] program ~;

[computer+vt] ~ carry out (operations);

A computer is an electronic device that manipulates information or data.

Related terms

data;* information;

A computer is an electronic device designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations.

A digital computer is a universal electronic data processing equipment.

Related terms


A computer is an electronic machine that can store and deal with large amounts of information.

A computer is an electronic machine that can quickly make arithmetical calculations, store, rearrange, and retrieve information, or control another machine.


[computer+vt] ~ make (calculations); ~ store (information); ~ rearrange (information); ~ retrieve (information); ~ control (machine);

ENIAC was the first programmable, electronic, general-purpose digital computer which was completed in 1945. (Wikipedia)


[adj+computer] programmable ~; general-purpose ~;

The main hardware units of a von Neumann computer are a control unit, an arithmetic and logic unit (ALU), a main memory, and input and output facilities.

Related terms


This tutorial will help you understand how computers work and how to use them.


[computer+vi] ~ work;
[vt+computer] use ~;

If you are just looking to learn more about how computers work, you will find all of the information you need in this tutorial.

We'll talk about how to set up a new computer, the difference between hardware and software, and so on.

Related terms

hardware;* software;*


set up, put together, assemble;

You can use a computer to do many things, for example to type documents, send emails, browse the Web, create and edit spreadsheets, presentations and even videos, play games, and so on.

After we have bought a new computer, the first thing we have to do is to set up and configure it.


[vt+computer] set up ~; configure ~;

Everything you do on your computer will rely on both hardware and software.


rely on, depend on; ≼be based on; ≺need, require;



The address of a specific data item refers to its location within the main memory of the computer.

addressing scheme

Addressing schemes are the wide variety of schemes developed in order to provide compact or convenient address references to the operands of the instructions available for a given processor.


An algorithm is a prescribed set of well-defined instructions or statements for the solution of a given problem in a finite number of steps (e.g. the performance of a calculation).

The instructions or statements of the algorithm are usually encoded in a selected programming language.

application program

An application program is a computer software package that performs a specific function directly for the end user or, in some cases, for another application.

Examples of application programs are web browsers, computer games, word processors, spreadsheet applications, various kinds of presentation software, graphics software, and so on.


backward compatibility

Backward compatibility is the ability of a later and more capable computer to use a hardware unit developed for, or to directly execute a program written for an earlier and less capable computer.


backward compatibility; ↭ upward compatibility;*



The chipset is a set of integrated circuits that manages the data flow between the microprocessor, the memory, and the peripherals on the motherboard of the microcomputers.


The cloud or cloud computing is a metaphor for internet-based computing services that allow users to store, access and process data over the Internet instead of using the local computer's resources.

In the tutorial we'll also explore operating systems, applications, the Internet, the cloud, and a whole lot more.


A computer cluster is a set of computers that work together so that they can be viewed as a single system.

computer system

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.



Data is stored information which is usually organized in a structured way.

Related terms


Organized data, especially when they appear in the form of models, provide an abstract representation of reality.

Related terms


The computer has the ability to store, retrieve, and process data.


[computer+vt] ~ process (data);

[vt+data] store ~; retrieve ~; process ~;

Data are entered by terminal for immediate processing by the computer.

Related terms



[vt+data] enter ~;

data processing

Data processing (DP) is the process of selecting and operating on data to produce useful information, e.g. by way of sorting and/or organizing data files.

Related terms

data;* information;*

data representation

Data representation is the coding rules and internal format applied to the different classes of primitive and complex data types defined in a computer system.

Related terms

data type;* coding rules; format;

data type

Data type defines the way a particular data item or unit is represented and interpreted by the computer.

Examples of primitive data types are integers, real numbers, logical values and characters.

Examples of complex data types are strings, arrays, and database records.


Colloquially, a database is a collection of data on some subject however defined, accessed, and stored within a computer system.

Strictly, a database is a structured collection of data held within a computer system using the facilities of a database management system or DBMS.


A digit is any of those one-character symbols of the positional number systems that are used for representing numbers.

In the binary number system 0 and 1 are binary digits or bits.

In the hexadecimal number system 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and A, B, C, D, E, F are hexadecimal digits.


A digital device uses sequences of digits to represent data that are used during its operation.

Related terms

digit;* data representation;*

A modern computer is a digital electronic machine that can be programmed to carry out sequences of arithmetic, logical or other type of operations using binary representation of data.

Related terms




All digital computers today are built up from electronic circuitry.

An electronic circuit establish a connection between electronic components that perform a specific function.


grid computing

Grid computing is the use of widely distributed computer resources to reach a common goal.



Computer hardware is the physical portion of the computer system including any part of the computer that has a physical structure.


hardware;* ↭ software;*

The hardware of a personal computer includes all of the computer's internal parts and external components, such as the motherboard, processor, main memory etc., and the monitor, keyboard, mouse etc., respectively.



In a technical sense, information is retrieved data which can be used for a specific purpose.


An instruction is the description of an operation that is to be performed by the processor of a computer.

Related terms


An instruction is a command to the processor of a given computer system.

An instruction is normally made up of a combination of an operation code and the specification of the operands that present or refer to the data upon which the operation is to be performed.

instruction set

An instruction set is the of instructions that a processor of a given computer system is capable of performing.

Related terms


The instruction set of a given computer system includes the list of all the operation codes, the specification of the operands, and the permitted addressing schemes pertinent to each instruction.



A motherboard (or mainboard) is the main printed circuit board (PCB) in general-purpose computers.

The motherboard (MB) allows communication between many of the crucial electronic components of the computer system (e.g. the CPU, main memory etc.).



A computer network is a number of computers, terminals and peripherals connected together to allow communications between each.



An operation is any procedure, such as addition, multiplication, set union, conjunction etc., that generates a unique value according to mechanistic rules from one or more given values as arguments.

The fundamental operations of arithmetic are taken to be addition, subtraction, multiplication, division and exponentiation.

The operation code (or op code) is usually the first portion of the instruction that specifies the operation to be performed by the computer.

Related terms


Each statement is composed of a predefined sequence of given operations to be performed.


consist of; be composed of; be made up of; be build up from;



A computer program consists of a given set of instructions or statements that can be executed by a computer in order to carry out a clearly defined task.

Related terms

instruction;* statement;

Computer programs formally describe and implement algorithms in a formal notation by way of one of the programming languages supported by the software of the computer system.

A program written in a high-level programming language is a sequence of statements.

The programs, especially the application programs enable computers to perform a wide range of tasks.

A program for a von Neumann computer consists of a set of instructions that are examined and executed sequentially, that is, one after another.

Related terms


An instruction is the smallest unit of a program which is executed directly by the processor.


relational database

A relational database applies a data model that views data as a collection of distinctly named two-dimensional tables some of which can be joined together to produce larger tables.

In the relational database model the cells within a particular column of a table always contain atomic or single data items which must be all of the same type.



Computer software is the intangible portion of the computer system consisting of all the programs that can be executed by the computer in order to produce a desired behaviour from the computer.


hardware;* ↭ software;*

Computer software tells the hardware what to do and how to do it by giving detailed and precise instructions to the hardware units concerned.


instruction, statement; ≼ program;* ≺ software;*

The software of a computer includes a set of cooperating programs that control the operation of the computer hardware, such as the operating system, drivers, utilities, software development environments, application programs etc.


Spreadsheets are interactive tables that contain selected pieces of information in their cells including numerical data, formulas, texts and other types of data.

Interactive tables can be manipulated by spreadsheet programs which store the data of the tables in files with dedicated extensions (e.g. xls or xlsx).



A computer terminal is a simple data input and/or output device that is connected to a usually remote computer.

Related terms

input; output

Using a terminal, the user can control a remote computer interactively by typing commands through a text-based interface to the computer.

Colloquially, a terminal can be considered as a stand-alone keyboard with a connected monitor.


upward compatibility

Upward compatibility is the ability of a new hardware unit developed for, or of a computer program written for a later and more capable computer to be used, or to be directly executed by an earlier and less capable computer.


upward compatibility; ↭ backward compatibility;*


word processor

A word processor is a program that enables its users to manipulate electronic documents with maximum flexibility so that they can easily compose, format, edit, store, or even print their documents.

MS Word is a versatile and widely used word processor which is very popular nowadays in many workplaces, for example in schools, colleges, universities, hospitals, and offices.

Tests for practice

Let's find out the missing word :-)

Change the font-size: 5% 8% 10%

[Click on the 'Next' button!]

What is a computer? – Digital computer

A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Each operation is described by a specific instruction to be performed. Modern digital electronic computers have a generic set of operations and instructions, and they have the capability to execute specific sets of them known as programs. The programs enable computers to perform a wide range of tasks.

digital computer;* operation;* instruction;* instruction set;* program*

A working definition of a digital computer:

A digital computer is a digital electronic machine that can be programmed to carry out sequences of operations automatically.

What does digital mean?

A digital computer is a universal electronic data processing equipment which uses fixed-length sequences of binary digits to represent elementary or primitive types of data (e.g. whole numbers or integers, real numbers, logical or Boolean values, characters etc.). The representation of data imposes specific coding rules and internal format upon each of the primitive and complex data types defined in a computer system.

data processing*
digital;* digit;* data type(s);* data representation*

Some examples of the coding rules and internal format of a few elementary data types:

Complex data types, e.g. strings, texts, long texts (cf. the "memo" field type, MS Access), arrays, database records etc., and various types of digital media (such as animations, digital images, sounds, videos etc.) also use binary encoding but the length and the number of the sequences of bits identifying elementary data units can be extremely diverse. For example, in a digital audio CD an elementary data unit can be 16 bits long (identifying the sound intensity at a given moment in one stereo channel), and the number of elementary data units depends on the actual length of the digitized sound.

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 group of computers that are linked and function together in order that the interconnected computers, as well as their users, can cooperate with each other effectively and efficiently to achieve a certain goal. Typical examples are computer networks* in general (including local area networks, the Internet etc.), computer clusters,* cloud computing* and grid computing.*

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.

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.

What is a computer? – Computer hardware

Conventionally, the central unit of a modern digital* computer* consists of at least one processing element, typically a central processing unit (CPU) in the form of a microprocessor, along with some type of computer memory. Both the CPU and the memory are typically made of semiconductor chips.
    In the processing element the arithmetic and logic unit (ALU) carries out arithmetic and logical operations,* and a sequencing and control unit (CU) reads and interprets the instructions* of the running program* sequentially. In some cases the CU can change the order of operations, e.g. in response to stored information.*
    Peripheral devices include input devices (keyboards, mice, joysticks, microphones, cameras etc.), output devices (monitors, printers, loudspeakers, projectors etc.), and input/output devices that perform both functions (e.g. the 2000s-era touchscreens).
    Storage units (e.g. HDDs or SSDs, optical drives and discs like CDs or DVDs, USB flash drives etc.) and network* adapters can also be considered as input/output devices. Such peripheral devices allow information to be retrieved from internal or external sources, and they enable the results of operations to be saved and retrieved again for further processing.*

Computer hardware* is the physical portion (i.e. the technically implemented units) of a digital computer. Some of the main hardware units of a desktop computer are as follows:

The computer can operate automatically, that is, it is capable of executing the currently running program by itself, without any human intervention. At hardware level, the basis for the automatic operation is provided by the instruction cycle executed by the control unit through endless repetitions.

What is a computer? – Early computers

Early computers were meant to be used only for calculations. Simple manual instruments like the abacus have aided people in doing calculations since ancient times. Early in the Industrial Revolution, some mechanical devices were built to automate long, tedious tasks, such as guiding patterns for looms. More sophisticated electrical or electromechanical machines (e.g. Konrad Zuse's Z3) did specialized analog or digital calculations in the early 20th century. The first digital* electronic* calculating machines were developed during World War II. The first programmable, electronic, general-purpose digital computer was the famous ENIAC which was completed in 1945.
    The vacuum tubes and the first discrete semiconductor components like diodes and bipolar transistors were followed by the silicon-based monolithic integrated circuit or chip technologies in the late 1950s. Integrated circuits were integrating a gradually increasing number of tiny transistors into one single semiconductor chip. This gradually lead to the development of the microprocessor and in turn the microcomputer revolution in the 1970s. The speed, power and versatility of computers* have been increasing dramatically ever since then, with transistor counts increasing at a rapid pace (as predicted by Moore's law). Along with the rapid development of wide-area computer networks* like the Internet, this lead to the Digital Revolution during the late 20th to early 21st centuries.

What does electronic mean?

The main hardware units of an electronic computer (e.g. the central unit, the motherboard, extension cards etc.) consist of electronic components for the most part, such as resistors, capacitors, diodes, transistors, integrated circuits etc.

In terms of the logic functions and logical operations that electronic circuits technically implement, logic gates and circuits form the basis of how the computer works.

What is a computer? – Computer software

A computer* is an inanimate device that has no intelligence of its own and must be supplied with instructions* so that it knows what to do and how and when to do it. Colloquially, the totality of these instructions are called software.* The importance of software can't be overestimated. You might have what most people consider the "best" computer sitting on your desk in front of you; however, without software to "feed" it, the computer will do nothing more than take up space.
    Software is made up of a group of related programs,* each of which consists of a given set of instructions or statements that perform very specific processing* tasks. Software can generally be divided into three categories: systems software, applications software,* and software development tools.
    The systems software called the operating system consists of programs designed to function as the principal interface between all the hardware* and software components, the currently running application programs, and the user(s) of the computer. In many ways, systems software functions in the same way as a business manager who tells and instructs the "hardware" and "software" components of the business what to do and how and when to do it while coordinating complex business tasks, and communicating with the "external" actors of business life. Applications software is a collection of related programs designed primarily to be carried out by a computer to satisfy the users' specific needs. Those programs are usually created by software development tools.

In general, software refers to a certain set of computer programs that can be executed by a computer system. Specifically, the actual or running software of a computer system consists of a system of mutually cooperating programs, including e.g.

A computer program is a sequence of instructions or statements that can be executed by the computer in a well-defined order so as to produce a desired output by processing the input and the stored data.

In general, the terms 'algorithm' and 'operation' are closely related to the mathematical concept of the function. Particularly, an operation is a function from the m-ary Cartesian product SxSx...xS into S itself, where 'm' is a natural number (usually 1 or 2, called a unary or binary operation, respectively), and 'S' is some set specific to the function.

Here, the term Cartesian product is central. The Cartesian product or cross product is a set of ordered n-tuples the elements of which are respectively members of the sequence of given sets. For example, the Cartesian product AxBxC is the set of all triples (a,b,c) where 'a' is a member or element of the set 'A', 'b' is a member of 'B', and 'c' is a member of 'C'. (Note that if the sets A, B and C are finite, and the number of elements of the sets are |A|=q, |B|=r, and |C|=s, respectively, then there are exactly q*r*s triples in the Cartesian product AxBxC.)

What is a computer? – Computer applications

A broad range of industrial and consumer products use computers* as control systems. Simple special-purpose devices like microwave ovens and remote controls are included, as are factory devices like industrial robots. There are general-purpose devices as well like personal computers and mobile devices like smartphones which are capable to run a lot of different applications.* Computers power the Internet, which links billions of other computers and users.

In this context, universal means that today's computers are extremely and amazingly versatile. In the first place, the programs are what enable computers to perform a wide range of tasks. To be more specific, computers are suitable to perform, in one way or another, almost any data processing task. Therefore present-day computers provide an enormous number of applications in almost all areas of the modern economy and society.

Some of the more important applications are as follows:

In addition to the purely data processing applications, the capability of computers of being able to control other machines is of vital importance. We can try the RoboMind robot simulation program to get a basic idea of how the computer control works.

Tests for practice

Let's find out the matching pairs :-)

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Borowski, E. J. – Borwein, J. M. 1989. Dictionary of Mathematics. London – Glasgow: Collins.

Burrell, Mark 2017. Fundamentals of Computer Architecture. Bloomsbury. (2023-05-24)

Collin, S. M. H. 2002. Dictionary of Information Technology. London: Peter Collin Publishing.

Collins COBUILD English Dictionary. London: HarperCollins Publishers. 1997.

GFC Global: Computer Basics.
Computer Basics - Tutorial (2023-02-14)

Gunton, Tony 1992. Dictionary of Information Technology and Computer Science. London etc.: Penguin Books.

Illingworth, Valerie – Pyle, Ian 1996. A Dictionary of Computing. Oxford – New York etc.: Oxford University Press.

Oxford Collocations Dictionary for Students of English. Oxford University Press, 2002.

Stallings, Warren D. – Hutchinson, Sarah E. – Sawyer, Stacey C. 1988. Computers. The User Perspective. St. Louis – Toronto – Santa Clara: Times Mirror – Mosby College Publishing.

Random House Webster's Unabridged Dictionary. New York: Random House Reference, 2009.

Roget's Thesaurus of English Words and Phrases. (ed. by Kirkpatrick, Betty) Penguin Books, 1987.

TechTarget - Software Quality (2023-03-23)

Wikipedia (in English) (2023-03-23)

Boda István, 2023.