Basic IT concepts

Content

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:

• read every lesson of the material very carefully and many times (see 'Recommended reading' above)
  • read some parts of the text aloud with special care of the pronunciation and intonation
  • Be aware that in a sentence every word is important. Memorizing a sentence is a very effective way to learn a set of related words at the same time and improve your mental lexicon.
  • after every sentence you read ask some questions and try to answer them; e.g. in case of the sentence A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. the following questions can be asked:
    • What is a computer? What does it mean 'to program a computer'? What does a 'program' consist of? (e.g. instructions) What are the main parts of a computer system? What kind (or sort) of computers do you know? What data types can a computer handle (or use)? What types of operations can a computer carry out?
    • What does the word 'automatically' mean? What is the opposite of the expression 'to work automatically'? (e.g. 'to be controlled manually') What synonyms do you know for the verb 'to carry out'? Can you tell the sentence 'A computer carries out sequences of operations automatically.' in another way?
    • Could you give some examples of 'arithmetic or logical operations'? What is the difference between 'an operation', 'a set of operations' and 'a sequence (or a series) of operations'? Could you explain the relationship between an 'instruction' and an 'operation'?
  • try to learn the content of the material; create mind maps of the keywords and use your visual memory
  • watch and listen to the attached videos
• try to understand the text from the beginning to the end; translate every unknown word (both technical terms and words belonging to the basic vocabulary), create your own vocabulary^⇒, and add new items to your vocabulary
  • hunt for new definitions on the Internet, e.g.
    = A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. (Wikipedia)
  • try to find good examples for each term, e.g.
    ~ ENIAC was the first programmable, electronic, general-purpose digital computer, completed in 1945. (Wikipedia)
  • collect useful example sentences, e.g.
    -- A broad range of industrial and consumer products use computers as control systems. (Wikipedia)
  • Collins Example Sentences is a database of authentic English examples extracted from Collins resources. Whilst a definition can help you understand the meaning of a word, example sentences show you how to use the word in a sentence. They can also help you check that you've understood the meaning correctly, as well as enabling you to see and learn the linguistic features of the word. If you're looking to improve your writing, example sentences can also give you ideas for other words that naturally occur in similar contexts. (Collins English Sentences, 2023-02-20)
  • use the excellent monolingual English dictionaries that are freely available on the Internet
    • Collins English Dictionary
    • Cambridge English Dictionary
    • Macmillan English Dictionary
    • Longman Dictionary of Contemporary English
    • Oxford Learner's Dictionaries
    • Merriam-Webster English Dictionary
    • Chambers English Dictionary
  • other links which can be very useful
    • Google Translate (2023-02-08)
  • use the Notepad (or another text editor) to create your own vocabulary, e.g.
  • ...
    
    --------
    computer
    --------
    = A digital computer is a digital electronic machine that can be programmed to carry out sequences of operations automatically.
    = A computer is an electronic device that manipulates information or data. (Tutorial)
    = 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. (Webster 2009)
    = A digital computer is a universal electronic data processing equipment.
    = A computer is an electronic machine that can store and deal with large amounts of information. (Collins 2023)
    = A computer is an electronic machine that can quickly make calculations, store, rearrange, and retrieve information, or control another machine. (Collins 1997)
    
    ~ ENIAC was the first programmable, electronic, general-purpose digital computer, completed in 1945. (Wikipedia)
    
    -- This tutorial will help you understand how computers work and how to use them. (Tutorial)
    -- If you are just looking to learn more about how computers work, you will find all of the information you need in this tutorial. (Tutorial)
    -- We'll talk about how to set up a new computer, the difference between hardware and software, and so on. (Tutorial)
    -- A broad range of industrial and consumer products use computers as control systems. (Wikipedia)
    
    ...
• try to analyse and memorize the definitions and example sentences of the vocabulary word-by-word
• (1) the definition of the keywords follow a general structure including three main parts:
  • the keyword, that is, the term (word or phrase) to be defined
    [e.g. A digital computer^* is a digital electronic machine that can be programmed to carry out sequences of operations automatically.]
  • the generic or broader term (the class of objects, concepts etc.) to which the keyword belongs; sometimes the meaning of the generic term is restricted or narrowed (e.g. by an adjective)
    [e.g. A digital computer is a digital electronic machine that can be programmed to carry out sequences of operations automatically.]
    → computer BT machine
    → machine NT electronic machine
    • sometimes this part of the definition is omitted
      [e.g. A digital^* device [is a device that] uses sequences of digits to represent data that are used during its operation.]
  • the special or differentiating characteristics that distinguish the keyword from the other terms that belong to the same generic term
    [e.g. A digital computer is a digital electronic machine that can be programmed to carry out sequences of operations automatically.]
    → computer RT program
    → computer RT (arithmetic, logical etc.) operation
• (2) the example sentences provide a valid context for the selected term
  • the words that come before or after the selected term suggest what the actual meaning of the term is
    • every example sentence makes a small contribution to the meaning of the selected term (note that a sentence is the smallest building block of texts that describe certain pieces of the world)
    • every example sentence belongs to one or more topic
  • from the example sentences we can get clever ideas about which words can naturally occur together with the selected term and how can you combine them; there are a lot of possible collocation patterns, e.g.
    → [adj+computer] digital; electronic; general-purpose, universal; local; remote; desktop, laptop; home, personal; mainframe; etc.
    → [vt+computer] use (to do sth); switch on, switch off; reboot, restart; set up, configure; program (to do sth); control; etc.
    → [computer+vi] work; freeze, crash; etc.
    → [computer+vt] manipulate, process (data / information); calculate, work out (value / sum); store, rearrange, retrieve (data / information); do, carry out, perform (operation / instruction / task); run, execute (program); control (computer / robot); etc.
• use the test at the end of this page and practise as much as possible
• generate new sentences; select a sentence or a sentence pattern (i.e. a verb pattern), and try to change it by
  • replacing certain words with new ones, e.g. synonyms or antonyms (e.g. machine ∼ device; hardware ↭ software), related or contrasted terms (e.g. machine ≼ instrument), narrower or broader terms (e.g. machine ≺ equipment) etc. (tip: use the 'Thesaurus' sections of the lexicon below which give semantic information about the corresponding terms)
  • adding new linguistic elements, e.g. adjectives, adverbs etc. (tip: use the 'Collocations' sections of the lexicon below which give semantic and syntactic information about the corresponding terms; collocations can be considered as patterns which help you to create a particular sentence)
• compose short texts and/or create presentations around selected keywords using the definitions, the example sentences, the texts of the tutorial and other relevant sources (e.g. Wikipedia entries)
  • collect the relevant keywords that belong to the same topic in order to build the theme-rheme relationships between the sentences (tip: use the 'Related terms' sections of the lexicon below which provide information at text linguistic or textological level)
• and so on :-)

Index of terms

• address^⇒
• addressing scheme^⇒
• algorithm^⇒
• application program^⇒
• backward compatibility^⇒
• chipset^⇒
• cloud^⇒
• computer^⇒
• cluster^⇒
• data^⇒
• data processing^⇒
• data representation^⇒
• data type^⇒
• database^⇒
• digit^⇒
• digital (device, machine etc.)^⇒
• electronic (circuit, components, device, machine etc.)^⇒
• grid computing^⇒
• hardware^⇒
• information^⇒
• instruction^⇒
• instruction set^⇒
• motherboard^⇒
• network^⇒
• operation^⇒
• program^⇒
• relational database^⇒
• software^⇒
• spreadsheet^⇒
• terminal^⇒
• upward compatibility^⇒
• word processor^⇒

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.^⇒

Keywords:
digital computer;^* operation;^* instruction;^* instruction set;^* program^*

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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.

Keywords:
data processing^*
digital;^* digit;^* data type(s);^* data representation^*

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

• examples of the coding rules and internal format of 8-bit integers:
  • 0 → 0000|0000
  • 23 → 0001|0111
  • −12 ⇒ 256−12=244 → 1111|0100
• examples of the coding rules and internal format of real ("floating point") numbers:
  • 4.5=1.125*2² ⇒ +(1+0.125)*2¹²⁷⁺² → 0 10000001 0010...
  • −2.25=−1.125*2¹ ⇒ −(1+0.125)*2¹²⁷⁺¹ → 1 10000000 0010...
  • 0.75=1.5*2⁻¹ ⇒ (1+0.5)*2¹²⁷⁻¹ → 0 01111110 1000...
  • −3=−1.5*2¹ ⇒ −(1+0.5)*2¹²⁷⁺¹ → 1 10000000 1000...
• examples of the coding rules and internal format of logical values:
  • true ⇒ 1 → 00000001
  • false ⇒ 0 → 00000000
• examples of the coding rules and internal format of ASCII characters (represented by a sequence of 7 bits):
  • ' ' ⇒ 32 → 0010|0000
  • '0' ⇒ 48 → 0011|0000
  • 'A' ⇒ 65 → 0100|0001

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.^*⇒

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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 the computer architecture which is 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.)

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

• black box model: A black box is metaphor of an open system that is described or viewed only in terms of its inputs and outputs. In other words, only the input and output data exchange between the computer and the environment is considered important or taken into consideration. That is because we either do not have any knowledge of the systems's internal workings, or just do not have much interest in it. Metaphorically, a system is a black box whose outer surface is considered opaque.
• white box model: A white box is a system where the inner components and their connections, and/or the (working or operating) logic of the system are available for thorough inspection. Note that the computer will gradually become a white box when we learn how the computer can transform input data into output results in particular cases.

The black box model of the computer as a data processing machine can be illustrated as follows:

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.

• In this context, open systems refer to systems that have external interactions, i.e. they take their input from their environment, and at the same time they provide output for it. (The opposite of the open systems are isolated systems, which do not have interactions with their environment.)
• Mathematically the output values of the black box can be described as a function of the (given combination of the) input values and some "hidden" parameters that represent the current state of the black box. (The data that characterize the current state of the black box have been generated and stored by the black box itself during its previous operation. ) The Turing machine (TM) is a well-known application of this approach.
• A very popular buzzword is artificial intelligence nowadays, and many AI applications use neural networks (e.g. the justly famous Google Translate service). A neural network is a typical implementation of the black box model because,
  – on the one hand, when we teach or train the network, we first compile, very carefully, a set of inputs with their corresponding outputs, and try to get the network to "memorize" the relationships between them (i.e. by having the neural network establish and strenghten the inner parameters that characterize the input-output relationships). In this process we say that the neural network is "learning";
  – on the other hand, to check the correctness of the network we can use a kind of black box testing selecting random inputs and checking whether the network can really demonstrate the expected outputs (or not).

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.^*⇒

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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:

• electrical and/or electronic components, e.g.
  – microprocessor,
  – random-access memory or RAM,
  – motherboard,
  – expansion cards,
  – monitor,
  – solid state drive or SSD,
  – USB flash drives,
  – various interfaces, ports and sockets,
  – wires and cables,
  – etc.
• electromechanical components, e.g.
  – hard disk drive or HDD,
  – optical disc (CD, DVD or Blu-ray) drives,
  – keyboard,
  – mouse,
  – microphone or headset,
  – loudspeakers,
  – video camera,
  – cooler(s),
  – power supply,
  – etc.
• mechanical components (e.g. the computer case).

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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.

• The instruction cycle or fetch-execute cycle has two (or, actually, three) main steps which the control unit of the computer executes in an infinite cycle:
  1. in the first step the next instruction of the currently running program is obtained (i.e. "fetched") from the memory;
  2. in the second step the obtained instruction is executed;
  3. after the second step, or just before the first step, the computer examines whether or not an interrupt request has been sent, triggered or asked.
• When an interrupt signal indicates that a special asynchronous event occurred that needs to be handled (e.g. an I/O request sent, an error triggered, an action asked by the operator etc.), then
  • the current sequence of instructions is temporarily suspended;
  • the computer starts to execute a dedicated sequence of instructions called an interrupt handler (IH);
    • when the IH fulfilled its task, then the interrupt handling process ends and it gives the control back to the interrupted process;
  • the execution of the interrupted program, that is, the original sequence of instructions continues, as though nothing had happened.

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.^⇒

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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.

• A transistor is a semiconductor device which is one of the basic building blocks of modern electronics. Because the transistor can be used as an electronic switch to open or close the controlled circuit in response to a control signal, it is an ideal tool for implementing logic gates and circuits.
• An integrated circuit (IC) is a set of electronic circuits on one small flat piece or "chip" of semiconductor material (which is usually made of silicon). In this technology, large numbers of tiny transistors are integrated into a small chip. This results in circuits that are orders of magnitude smaller, faster, and less expensive than those constructed of discrete electronic components. Integrated circuits, having achieved very large-scale integration, are now used in virtually all electronic equipment and revolutionized the world of electronics.
  • Very large-scale integration (VLSI) is the technology of creating an integrated circuit by integrating millions of transistors into a single chip. For example, the microprocessor and the memory chips are VLSI devices. Today's microprocessors have many millions of logic gates and billions of individual transistors.

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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.

• A logic gate is a device that implements an elementary logic function; accordingly, we can speak about AND, OR, NAND, NOR etc. gates. (The gates implementing the NOT function are called inverters.) In order to represent the two logic states, in electronic logic gates two different voltage levels are used for the input and output signals. Usually the high voltage level represents true, and the low voltage level represents false.
• A logic circuit is a device that implements a complex logic function. It means that when receiving a specified binary input (that is, a certain combination of binary values), a logic circuit can produce a specified binary output. It is accomplished by several logic gates connected with each other to implement a given logic function (specified e.g. by a truth table). There are two different types of logic circuits:
  • In combinational circuits the output values are solely a function of the actual combination of the input values (and nothing else). For example, an adder is a combinational circuit.
  • In sequential circuits the output values are a function of both the actual combination of the input values and some preceding values or parameters that the circuit previously produced. Those parameters are called the states of the circuit which can be set by using feedbacks. For example, memory elements like flip-flops are sequential circuits.

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.^⇒

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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.

• the operating system (e.g. Microsoft Windows, Unix etc.), which is a kind of system software with basic functions that are essential for the operation of the computer. The operating system is usually called the main software of the computer system which
  – manages the computer's hardware and software resources,
  – offers common services for other programs,
  – provides a platform for running different applications,
  – enables the users to communicate with the computer,
  – etc.;
• utility software (e.g. Total Commander, Notepad, Paint, Media player etc.);
• application software (e.g. Microsoft Office, Google Chrome or Mozilla Firefox etc.).

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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.

• Programs formally describe ("encode") and implement algorithms in a formal notation by way of one of the programming languages supported by the software of the computer system.
• 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 of the algorithm are usually encoded in a selected programming language.
• A programming language is a formal notation for the precise description of algorithms in a form of computer programs. Programming languages are artificial languages in which the syntax (or grammar) and semantics are strictly defined.
  There are basicly three types of programming languages which enable the programmers to write the codes of programs at different levels.
  • A program written at the machine-code level is a sequence of instructions. An instruction is the description of an operation that is to be performed by a computer.
    • An instruction set is the set of instructions available in a particular computer. It contains e.g. the operation codes and the permitted addressing schemes supported by a given (micro)processor.
  • A program written in an assembly language allows the programmer to use alphabetic operation codes and other symbolic tools (e.g. symbolic names for the registers, addresses, labels for the instructions etc.) instead of using machine codes and physical addresses for each instructions.
  • A program written in a high-level language is constructed from statements. Each statement is composed of a predefined sequence of given operations to be performed. Some dedicated sequences of statements (called usually "functions") can be named so that they can be referred to by their name anywhere within the program.

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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.^⇒

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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:

• scientific and other calculations (note that early computers were meant to be used for calculations; that is why we are still using the term 'computer', i.e "computing machine");
• military applications; the early computers, as well as the internet itself, have a military origin, i.e. they were all military developments:
  – the first digital electronic calculating machines were developed during World War II (including the famous ENIAC);
  – the ancestor of the internet raised from a project funded by the ARPA, the Advanced Research Projects Agency of the US Department of Defense (hence comes the name of the world's first wide area packet switched network, the ARPANET);
• business applications: managing the companies' databases (e.g. about employees, stock of goods, trading, sales, the users' behaviour etc.), sales analysis, budgeting, accounting, advertising, offering online access and services, ordering, shopping, reservations etc.;
• education and learning applications: e-learning, learning management systems (LMS), a wide range of educational and learning materials etc.;
• communication: web 2.0 services (blogs, forums, wikis, social and community networks etc.), mobile networks and devices, telecommunications networks etc.;
• (public) information and content providing services: various web pages and sites, search engines (e.g. the Google), public databases and services (electronic libraries, open access journals, web shops, public transport timetables, ticket reservations etc.), mass media and news services, GPS services etc.;
• entertainment: computer games, ebook readers, mp3 players, YouTube videos, movie streaming services etc.;
• design, simulation and manufacturing: computer-aided engineering, computer-aided design and computer-assisted manufacturing (CAD/CAM) applications (e.g. design and production of integrated circuits in electronics industry);
• virtual reality; computers are also capable to simulate the operation of other computers and automatons, including the implementation of the Universal Turing Machine (UTM) as well;
  
• industrial and commercial applications: a broad range of industrial and consumer products use computers as control systems (e.g. washing machines, remote controls and controlled devices etc.; robot pilots, industrial robots etc.).

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.