Introduction to Computers Lecture 1 Prepared by Natalie Rose

Prepared by Natalie Rose Web Page and Book List Main Course Web Page is at: http://nnrose.weebly.com Recommended Text Shelly Cashman: Discovering Computer 2011 Prepared by Natalie Rose

Prepared by Natalie Rose Data vs. Information Data: Representation of a fact or idea Information: Organized, meaningful data Data is a representation of a fact or idea. Data can be a number, a word, a picture, or even a recording of sound. For example, the number 6125553297 and the names Derek and Washington are pieces of data. Information is data that has been organized or presented in a meaningful fashion. When your computer provides you with a contact listing that indicates Derek Washington can be reached by phone at (612) 555-3297, the data mentioned earlier suddenly becomes useful— that is, it is information. Prepared by Natalie Rose 3 5

Prepared by Natalie Rose Data, Information Data vs. Information Data (PLURAL) - SINGULAR IS DATUM A “given” or fact: a number, a statement, or a picture The raw facts in the production of information Information Data that have meaning within a context Raw data or data that have been manipulated Prepared by Natalie Rose

Computers Are Data Processing Devices Computer’s four major functions: Gathers data (users input data) Processes data into information Outputs data or information Stores data and information Strictly defined, a computer is a data processing device that performs four major functions: 1. It gathers data (or allows users to input data). 2. It processes that data into information. 3. It outputs data or information. 4. It stores data and information. Prepared by Natalie Rose 5 4

Prepared by Natalie Rose What Computers Do Basic Components of a Computer Input devices Keyboards and pointing devices (mouse) Output devices Display or video monitor Printer Speakers Central Processing Unit (CPU) Prepared by Natalie Rose

Prepared by Natalie Rose What Computers Do Basic Components of a Computer Memory and storage devices Primary storage: RAM (Random Access Memory) Secondary storage: Storage devices that serve as long-term repositories for data: Hard disk drives Recordable CD and DVD drives Tape drives Prepared by Natalie Rose

Components of a Computer System Input Output Central Processing Unit (CPU) Memory Control Unit Arithmetic Logic Unit Registers Prepared by Natalie Rose

Bits and Bytes: The Language of Computers Binary digit 0 or 1 Byte Eight bits Each letter, number, and character = a string of eight 0s and 1s In order to process data into information, computers need to work in a language they understand. This language, called binary language, consists of just two digits: 0 and 1. Everything a computer does is broken down into a series of 0s and 1s. Each 0 and 1 is a binary digit, or bit for short. Eight binary digits (or bits) combine to create 1 byte. In computers, each letter of the alphabet, each number, and each special character (such as the @ sign) consists of a unique combination of 8 bits, or a string of eight 0s and 1s. As it turns out, if 8 bits are put together there are 256 possible combinations that they can be in. That number of combinations allows for a code that can include all the uppercase and lowercase letters of the alphabet, all 10 digits, punctuation marks, and many other much-used symbols. We call these 8 bits working together a byte. Bytes are the basic measurement for storage in a computer. Prepared by Natalie Rose 9 6

Prepared by Natalie Rose A Bit About Bits Bits, Bytes, and Buzzwords Bit-related terminology Byte Kilobyte (KB) Megabytes (MB) Gigabytes (GB) Terabytes (TB) = 8 bits = 1 Thousand Bytes = 1 Million Bytes = 1 Billion Bytes = 1 Trillion Bytes Prepared by Natalie Rose

Chapter 2 Summary Questions What devices do you use to get data into the computer? What devices do you use to get data into the computer? Prepared by Natalie Rose 11 50

Chapter 2 Summary Questions What devices do you use to get information out of the computer? What devices do you use to get information out of the computer? Prepared by Natalie Rose 12 51

Chapter 2 Summary Questions What’s on the front of your system unit? What’s on the front of your system unit? Prepared by Natalie Rose 13 52

Chapter 2 Summary Questions What’s on the back of your system unit? What’s on the back of your system unit? Prepared by Natalie Rose 14 53

Prepared by Natalie Rose History of Computers Mechanical and electromechanical devices preceded the electronic computer. Charles Babbage (1830’s): the analytical engine, and Augusta Ada Byron, the first programmer. Prepared by Natalie Rose

Charles Babbage’s Analytical Engine Prepared by Natalie Rose

Electro-Mechanical Devices (1890’s): electrical tabulating machine, and foundation of IBM (1924). Aiken’s Mark 1. (1944) based on Babbage’s original design - built at IBM labs, electro-mechanical, weighed 5 tons. Admiral Grace Hopper worked as programmer on this computer, and coined in the term 'bug' for a computer fault. Prepared by Natalie Rose

Prepared by Natalie Rose Electronic Computers To increase speed and reliability, the mechanical components of these early devices were replaced by electronic equivalents. These fully electronic devices became known as the of computers. Successive generations of electronic computers have greater speed, smaller size, larger memory. Prepared by Natalie Rose

Prepared by Natalie Rose First Generation 1st Generation: (1945-1956). Vacuum Tubes used as switching and storage components. Atanasoff & Berry (1939) first electronic digital computer. Turing (1943) Colossus machine built to decode encrypted messages. (*Turing Test) ENIAC (1946) first general purpose computer. (decimal not binary machine) UNIVAC (1951) first commercial computer - commissioned for 1950 US census. Prepared by Natalie Rose

Prepared by Natalie Rose First Generation Problems with vacuum tube machines: severe overheating, manual setting of each instruction, use of machine language only. Magnetic core used for memory, punched cards and later magnetic tape for secondary storage. Computers used for scientific and government purposes. Prepared by Natalie Rose

Prepared by Natalie Rose First Generation In 1945 John von Neumann proposed the ‘stored program concept’, with memory to store both data and instructions. Loading a new program into memory then allows a new function for the computer. In Von Neumann’s basic design, the program is executed in a sequential manner. While still the model for most conventional computers, parallel processing has recently challenged this aspect of the traditional computing device Prepared by Natalie Rose

Prepared by Natalie Rose Second Generation 2nd Generation: (1956-1963). Transistors. Transistors replaced vacuum tubes. smaller, faster, more reliable, and use less energy Development of symbolic languages Simpler programming - eg ADD instead of 00000101, high level languages Fortran and Cobol. Provision of system software (OS). Computers used by military, government and big business. Problems: 100s or 1000s of transistors required for powerful machines, expensive and cumbersome This problem was solved by the invention of the integrated circuit Prepared by Natalie Rose

Prepared by Natalie Rose Third Generation 3rd generation: (1964-1971). Integrated Circuits. Complete electronic circuit on single silicon chip, smaller than single transistor. 1000’s of components on one chip. (SSI to MSI) cheap, fast and reliable. used by small business Prepared by Natalie Rose

Prepared by Natalie Rose Fourth Generation 4th generation: (1975-1984). Microprocessors Microprocessor contains ALL elements of CPU on one chip (Intel’s 4004, 1971). Progressively greater integration (from LSI to VLSI) - 100,000’s to millions of components per chip. Increasing complexity of instruction sets, no of bits handled at once, amount of memory addressed. Advent of personal computers and other microprocessor controlled devices. Prepared by Natalie Rose

Prepared by Natalie Rose Fifth Generation 5th Generation:Ultra Large Scale Integrated Circuits (ULSI): over 1 million Transistors per Integrated Circuit or Chip Prepared by Natalie Rose

Performance Enhancements Computer performance has been greatly enhanced by the following : Faster clock speed Overlapping & Parallel instruction processing Wider, faster data paths (Buses) Faster disk access Bigger and Faster memory, including advanced cache technology Optimised software Prepared by Natalie Rose