Fundamental concepts of Information Technology A brief history, the Neumann architecture, the language of computers Csernyi Gábor Department of English Linguistics University of Debrecen Csernyi Gábor (DE IEAS) Fundamental concepts of IT 1 / 17
Table of contents 1 A brief history Computer generations 2 The Neumann architecture The Neumann-principles The conceptual architecture of computers 3 The language of computers Representing numbers Logic gates Representing text Csernyi Gábor (DE IEAS) Fundamental concepts of IT 2 / 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 and Hermann Goldstine: ENIAC machine (Neumann s importance!) Neumann & Goldstine: the formulation of the requirements of the electronic digital computer the (von-)neumann principles storage: punch card, tape huge computers with high energy consumption, air conditioners needed to reduce heat produced by computers warm-up time electric failures lower-level programming, machine language Csernyi Gábor (DE IEAS) Fundamental concepts of IT 3 / 17
A short history: computer generations (2) Second generation ( 1955-64): invention of transistor: Walter Brattain, John Bardeen & William Shockley (1947) compared to the vacuum tube: less energy consumption, less heat smaller but faster higher reliability no warm-up time storage devices: removable disk, magnetic tape the development of the first high-level programming language: FORTRAN Csernyi Gábor (DE IEAS) Fundamental concepts of IT 4 / 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 chip magnetic core memory replaced by microchip operating systems keyboard, screen mass production Intel (INTegated ELectronics) (1968) small-scale integration (SSI), medium-scale integration (MSI) Gordon Moore s prediction (that the number of transistors on an integrated chip will double every year (1965)) still holds Csernyi Gábor (DE IEAS) Fundamental concepts of IT 5 / 17
A short history: computer generations (4) Fourth generation ( 1974-mid-1990s): nanotechnology microprocessor parallel processing first IBM PCs (1981) and Apple computers (1983) graphical user interface (GUI) small and faster integrated circuits higher capacity memory types large-scale integration (LSI) Csernyi Gábor (DE IEAS) Fundamental concepts of IT 6 / 17
A short history: computer generations (5) Fifth generation ( mid-1990s-): artificial intelligence, problem solving expert systems robotics natural language Csernyi Gábor (DE IEAS) Fundamental concepts of IT 7 / 17
The Neumann-principles 1 Executing the instructions sequentially. also note: multiprocessor computers Csernyi Gábor (DE IEAS) Fundamental concepts of IT 8 / 17
The Neumann-principles 1 Executing the instructions sequentially. also note: multiprocessor computers 2 Completely electronic computer, using the binary system. lower voltage: 0; higher voltage: 1 Csernyi Gábor (DE IEAS) Fundamental concepts of IT 8 / 17
The Neumann-principles 1 Executing the instructions sequentially. also note: multiprocessor computers 2 Completely electronic computer, using the binary system. lower voltage: 0; higher voltage: 1 3 Internal memory. Csernyi Gábor (DE IEAS) Fundamental concepts of IT 8 / 17
The Neumann-principles 1 Executing the instructions sequentially. also note: multiprocessor computers 2 Completely electronic computer, using the binary system. lower voltage: 0; higher voltage: 1 3 Internal memory. 4 Program is stored in the (same) memory as data: the computer is a stored program machine. Csernyi Gábor (DE IEAS) Fundamental concepts of IT 8 / 17
The Neumann-principles 1 Executing the instructions sequentially. also note: multiprocessor computers 2 Completely electronic computer, using the binary system. lower voltage: 0; higher voltage: 1 3 Internal memory. 4 Program is stored in the (same) memory as data: the computer is a stored program machine. 5 Universal computer. Csernyi Gábor (DE IEAS) Fundamental concepts of IT 8 / 17
The conceptual architecture of computers Csernyi Gábor (DE IEAS) Fundamental concepts of IT 9 / 17
Representing data Number systems: ternary (base 4) digits: 0-3 octal (base 8) digits: 0-7 decimal (base 10) digits: 0-9 hexadecimal (base 16) digits: 0-9, A-F Neumann principles computers use the binary number system. practice Representatoin, conversion from one number system to another, basic mathematical operations (adding, multiplying). Csernyi Gábor (DE IEAS) Fundamental concepts of IT 10 / 17
Logic gates (1) Statements: true / false 1: true 0: false NOT: A NOT A 1 0 0 1 Csernyi Gábor (DE IEAS) Fundamental concepts of IT 11 / 17
Logic gates (2) AND: A B A AND B 1 0 0 1 1 1 0 0 0 0 1 0 Csernyi Gábor (DE IEAS) Fundamental concepts of IT 12 / 17
Logic gates (3) OR: A B A OR B 1 0 1 1 1 1 0 0 0 0 1 1 Csernyi Gábor (DE IEAS) Fundamental concepts of IT 13 / 17
Logic gates (4) XOR (exclusive OR): A B A XOR B 1 0 1 1 1 0 0 0 0 0 1 1 Csernyi Gábor (DE IEAS) Fundamental concepts of IT 14 / 17
Representing text (1) 1 BCD (Binary Coded Decimal) 4 bits for each decimal (3 bits would not be enough; the maximum number that can be represented with 4 bits is 2 3 + 2 2 + 2 1 + 2 0 = 15) e.g.: 127 = 0001 0010 0111 1 2 7 Csernyi Gábor (DE IEAS) Fundamental concepts of IT 15 / 17
Representing text (2) 2 EBCDIC (Extended Binary Coded Decimal Interchange Code) the extension of BCD: additional four bits, the first four called the zone (which group the character is in), the second four called the digit (the code of the character) Csernyi Gábor (DE IEAS) Fundamental concepts of IT 16 / 17
Representing text (3) 3 ASCII (American Standard Code for Information Interchange) the original version used 7 bits for representation: to code numbers, control characters (e.g.: return), and letters of the English alphabet maximum of 127 characters can be represented (=7 bits 2 6 + 2 5 +... + 2 0 = 127) later extended: 8 bits used for representation, to code letters not included in the English alphabet (+128 characters can be coded) this additional bit is used for defining code pages problematic issue: inconsistency (two different characters with the same code in two different code pages) solution: UNICODE number of bits used for representation: 16 (65536 characters can be represented!), then extended to 32 advantage: no code pages, consistent among languages Csernyi Gábor (DE IEAS) Fundamental concepts of IT 17 / 17