Fundamental Concepts Of Information Technology

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Fundamental concepts of Information TechnologyA brief history, the Neumann architecture, the language of computersCsernyi GáborDepartment of English LinguisticsUniversity of DebrecenCsernyi Gábor (DE IEAS)Fundamental concepts of IT1 / 17

Table of contents1A brief historyComputer generations2The Neumann architectureThe Neumann-principlesThe conceptual architecture of computers3The language of computersRepresenting numbersLogic gatesRepresenting textCsernyi Gábor (DE IEAS)Fundamental concepts of IT2 / 17

A short history: computer generations (1)First generation ( 1946-54):development of the vacuum tube: Lee de Forest (1906)Presper Eckert and John Mauchly, together with Neumann János andHermann Goldstine: ENIAC machine (Neumann’s importance!)Neumann & Goldstine: the formulation of the requirements of theelectronic digital computer Ô the (von-)Neumann principlesstorage: punch card, tapehuge computers with high energy consumption, air conditionersneeded to reduce heat produced by computerswarm-up timeelectric failureslower-level programming, machine languageCsernyi Gábor (DE IEAS)Fundamental concepts of IT3 / 17

A short history: computer generations (2)Second generation ( 1955-64):invention of transistor: Walter Brattain, John Bardeen & WilliamShockley (1947)compared to the vacuum tube:Iless energy consumption, less heatIsmaller but fasterIhigher reliabilityIno warm-up timestorage devices: removable disk, magnetic tapethe development of the first high-level programming language:FORTRANCsernyi Gábor (DE IEAS)Fundamental concepts of IT4 / 17

A short history: computer generations (3)Third generation ( 1965-74):development of IC (integrated circuit): Jack Kilby & Robert Noyce(1959)electronic circuit on silicon chipmagnetic core memory replaced by microchipoperating systemskeyboard, screenmass productionIntel (INTegated ELectronics) (1968)small-scale integration (SSI), medium-scale integration (MSI)Gordon Moore’s prediction (that the number of transistors on anintegrated chip will double every year (1965)) still holdsCsernyi Gábor (DE IEAS)Fundamental concepts of IT5 / 17

A short history: computer generations (4)Fourth generation ( el processingfirst IBM PCs (1981) and Apple computers (1983)graphical user interface (GUI)small and faster integrated circuitshigher capacity memory typeslarge-scale integration (LSI)Csernyi Gábor (DE IEAS)Fundamental concepts of IT6 / 17

A short history: computer generations (5)Fifth generation ( mid-1990s-):artificial intelligence, problem solvingexpert systemsroboticsnatural languageCsernyi Gábor (DE IEAS)Fundamental concepts of IT7 / 17

The Neumann-principles1Executing the instructions sequentially.also note: multiprocessor computersCsernyi Gábor (DE IEAS)Fundamental concepts of IT8 / 17

The Neumann-principles1Executing the instructions sequentially.also note: multiprocessor computers2Completely electronic computer, using the binary system.lower voltage: 0; higher voltage: 1Csernyi Gábor (DE IEAS)Fundamental concepts of IT8 / 17

The Neumann-principles1Executing the instructions sequentially.also note: multiprocessor computers2Completely electronic computer, using the binary system.lower voltage: 0; higher voltage: 13Internal memory.Csernyi Gábor (DE IEAS)Fundamental concepts of IT8 / 17

The Neumann-principles1Executing the instructions sequentially.also note: multiprocessor computers2Completely electronic computer, using the binary system.lower voltage: 0; higher voltage: 13Internal memory.4Program is stored in the (same) memory as data: the computer is astored program machine.Csernyi Gábor (DE IEAS)Fundamental concepts of IT8 / 17

The Neumann-principles1Executing the instructions sequentially.also note: multiprocessor computers2Completely electronic computer, using the binary system.lower voltage: 0; higher voltage: 13Internal memory.4Program is stored in the (same) memory as data: the computer is astored program machine.5Universal computer.Csernyi Gábor (DE IEAS)Fundamental concepts of IT8 / 17

The conceptual architecture of computersCsernyi Gábor (DE IEAS)Fundamental concepts of IT9 / 17

Representing dataNumber systems:ternary (base 4) digits: 0-3octal (base 8) digits: 0-7decimal (base 10) digits: 0-9hexadecimal (base 16) digits: 0-9, A-FNeumann principles Ô computers use the binary number system.practiceRepresentatoin, conversion from one number system to another, basicmathematical operations (adding, multiplying).Csernyi Gábor (DE IEAS)Fundamental concepts of IT10 / 17

Logic gates (1)Statements: true / false1: true0: falseNOT:A10Csernyi Gábor (DE IEAS)NOT A01Fundamental concepts of IT11 / 17

Logic gates (2)AND:A1100Csernyi Gábor (DE IEAS)B0101A AND B0100Fundamental concepts of IT12 / 17

Logic gates (3)OR:A1100Csernyi Gábor (DE IEAS)B0101A OR B1101Fundamental concepts of IT13 / 17

Logic gates (4)XOR (exclusive OR):A1100Csernyi Gábor (DE IEAS)B0101A XOR B1001Fundamental concepts of IT14 / 17

Representing text (1)1BCD (Binary Coded Decimal)4 bits for each decimal (3 bits would not be enough; the maximumnumber that can be represented with 4 bits is23 22 21 20 15)e.g.: 127 00011Csernyi Gábor (DE IEAS)0010201117Fundamental concepts of IT15 / 17

Representing text (2)2EBCDIC (Extended Binary Coded Decimal Interchange Code)the extension of BCD: additional four bits, the first four called thezone (which group the character is in), the second four called thedigit (the code of the character)Csernyi Gábor (DE IEAS)Fundamental concepts of IT16 / 17

Representing text (3)3ASCII (American Standard Code for Information Interchange)Ithe original version used 7 bits for representation: to code numbers,control characters (e.g.: return), and letters of the English alphabetmaximum of 127 characters can be represented( 7 bits Ô 26 25 . . . 20 127)Ilater extended: 8 bits used for representation, to code letters notincluded in the English alphabet ( 128 characters can be coded) thisadditional bit is used for defining code pages problematic issue: inconsistency (two different characters with thesame code in two different code pages) solution: UNICODEFnumber of bits used for representation: 16 (65536 characters can berepresented!), then extended to 32Fadvantage: no code pages, consistent among languagesCsernyi Gábor (DE IEAS)Fundamental concepts of IT17 / 17

Neumann principles Ô computers use the binary number system. practice Representatoin, conversion from one number system to another, basic mathematical operations (adding, multiplying). Csernyi G abor (DE