Introduction to computers


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Introduction to computers

  2. 2. INTRODUCTION TO COMPUTERS What is a Computer? Advantages/Features of Computer Definition of Computer History of Computer Generations of Computers Types of Computer Hardware & Software Parts of Computer (Block Diagram) Storage (I/O) Devices Software – System Software & Application Software Operating Software
  3. 3. INTRODUCTION TO COMPUTERSWhat is a Computer?The computer is one of the greatestinventions in the history ofhumankind. Computers haveapplications in all fields ofknowledge and therefore touch allaspect of our life whatever may beour field of activity.The computer can be defined as amachine that can do calculations,comparisons, reading and writing ona given set of data at a very highspeed, logically and intelligently in adesired manner.
  4. 4. INTRODUCTION TO COMPUTERSAdvantages / Features of ComputersSpeed – A computer performs operations withgreat speed.Accuracy – The computer gives accurateresults according to the instruction provided.Storage – The storage capacity of thecomputer is very largeVersatility – Computers are used in vide areasof human activities.Automatic – The computer performs all theinstructions provided to it automatically.Diligence – After long hours of work humanbeing gets tired but a computer never gets tired.
  5. 5. INTRODUCTION TO COMPUTERSDefinition of a ComputerA computer is an electronicdevice, which can performarithmetic and logical operationswith a high speed as perinstructions given.
  6. 6. INTRODUCTION TO COMPUTERSHistory of Computer 1642 – Pascal built Mechanical Calculating Machine  mechanical gears, hand-crank, dials and knobs  other similar machines followed 1805 – First Programmable device, Jacquard Loom  wove tapestries with elaborate, programmable patterns  pattern represented by metal punch- cards, fed into loom  could mass-produce tapestries, reprogram with new cards
  7. 7. INTRODUCTION TO COMPUTERSHistory of Computer Mid 1800s – Babbage designed "analytical engine"  expanded upon mechanical calculators, but programmable via punch-cards  described general layout of modern computers  never functional, beyond technology of the day 1890 – Hollerith invented tabulating machine  used for 1890 U.S. Census  stored data on punch-cards, could sort and tabulate using electrical pins  finished census in 6 weeks (vs. 7 years)  Holleriths company would become IBM
  8. 8. INTRODUCTION TO COMPUTERSHistory of Computer 1930s – several engineers independently built "computers" using electromagnetic relays  physical switch, open/close via electrical current  Zuse (Nazi Germany) – destroyed in WWII  Atanasoff (Iowa State) – built with grad student  Stibitz (Bell Labs) – followed design of Babbage
  9. 9. INTRODUCTION TO COMPUTERSGenerations of ComputersGeneration 1: Vacuum Tubes (1945-1954) mid 1940s – vacuum tubes replaced relays  glass tube w/ partial vacuum to speed electron flow  faster than relays since no moving parts  invented by de Forest in 1906 1940s – hybrid computers using vacuum tubes and relays were built COLOSSUS (1943)  built by British govt. (Alan Turing)  used to decode Nazi communications ENIAC (1946)  built by Eckert & Mauchly at UPenn  18,000 vacuum tubes, 1,500 relays  weighed 30 tons, consumed 140 kwatts
  10. 10. INTRODUCTION TO COMPUTERSGenerations of ComputersGeneration 2: Transistors (1954-1963) mid 1950s – transistors began to replace tubes  piece of silicon whose conductivity can be turned on and off using an electric current  smaller, faster, more reliable, cheaper to mass produce  invented by Bardeen, Brattain, & Shockley in 1948 (won 1956 Nobel Prize in physics) computers became commercial as cost dropped high- level languages were designed to make programming more natural  FORTRAN (1957, Backus at IBM)  LISP (1959, McCarthy at MIT)  BASIC (1959, Kemeny at Dartmouth)  COBOL (1960, Murray-Hopper at DOD)the computer industry grew as businesses couldbuy Eckert-Mauchly (1951), DEC (1957) IBM became market force in 1960s
  11. 11. INTRODUCTION TO COMPUTERSGenerations of ComputersGeneration 3: Integrated Circuits (1963-1973) integrated circuit (IC)  as transistor size decreased, could package many transistors with circuitry on silicon chip  mass production further reduced prices 1971 – Intel marketed first microprocessor, a chip w/ all the circuitry for a calculator 1960s saw the rise of Operating Systems  an operating system is a collection of programs that manage peripheral devices and other resources  allowed for time-sharing, where multiple users share a computer by swapping jobs in and out  as computers became affordable to small businesses, specialized programming languages were developed Pascal (1971, Wirth) C (1972, Ritche)
  12. 12. INTRODUCTION TO COMPUTERSGenerations of ComputersGeneration 4: VLSI (1973-1985) Very Large Scale Integration (VLSI)  by mid 1970s, could fit hundreds of thousands of transistors w/ circuitry on a chip  could mass produce powerful microprocessors and other useful ICs  computers finally affordable to individuals Late 1970s saw rise of personal computing  Gates & Allen founded Microsoft in 1975 Gates wrote BASIC compiler for personal computer would grow into software giant, Gates richest in world  Wozniak and Jobs founded Apple in 1977 went from garage to $120 million in sales by 1980  IBM introduced PC in 1980 Apple countered with Macintosh in 1984
  13. 13. INTRODUCTION TO COMPUTERSGenerations of ComputersGeneration 5: Parallelism & Networking (1985-????)In this generation the computers are supposed to useArtificial Intelligence.Japan initiated the fifth generation computer project itwas also known as knowledge processing system. Itused a very large scale parallel processingtechnologies and incorporated Artificial Intelligence.
  14. 14. INTRODUCTION TO COMPUTERSTypes of ComputerComputers can be classifies asfollows:Analog Computers: are used forprocessing data that vary continuouslysuch as speed, humidity etc. in suchcomputers data is given in continuousform. These computers are not capableof taking decisions but still are used inscientific and industrial establishments.
  15. 15. INTRODUCTION TO COMPUTERSTypes of ComputerDigital Computers: Digital computers performcalculations by counting and are used formanipulating data with great accuracy. Digitalcomputers are further classified into:a) General Purpose – computers are able to handle many complicated problems by using programs which are specially prepared for solving complicated problemsb) Special Purpose – computers are found in various consumer appliances, these are different from the computers used by business organization e.g. computers to identify mobile problems.
  16. 16. INTRODUCTION TO COMPUTERSTypes of ComputerHybrid Computer: It is a combination ofAnalog and Digital computers. Hybrid computerare used where continuous and digitalprocessing is required e.g. to monitor weatherthe analog devices may measure the humidity,temperature etc. the numbers are furtherconverted into numbers and supplied to digitalcomponent of the system.
  17. 17. INTRODUCTION TO COMPUTERSTypes of ComputerBased on the other features of the computersuch as speed, memory, processing power andcost computers are classified as follows:a) Micro Computer (Personal Computer)b) Desktopsc) Workstationsd) Multimediae) Laptopsf) Palmtopsg) Serversh) Mini Computersi) Mainframe Computersj) Super Computers
  18. 18. INTRODUCTION TO COMPUTERSHardware & Softwarei) Hardware : The hardware consist of the physical parts of the computer which can be touched, seen and felt.ii) Software: The full set of instructions and procedures to be used on the computer is called software. Software’s can be classified into: i) System Software (Operating System) ii) Application Software
  19. 19. INTRODUCTION TO COMPUTERSParts of Computer (Block Diagram) ALU Arthematic & Logical UnitINPUT OUTPUT CU Control Unit MU Memory Unit RAM & ROM
  20. 20. INTRODUCTION TO COMPUTERSInput Devices You use an input device, such as a keyboard or a mouse, to input data and issue commands  Keyboard  Mouse  Game Controller (Joystick)  Bar Code Reader  Scanner  Trackball  Touch Screen  Optical Mark Reader (OMR)  Magnetic Ink Character Recognition (MICR)  Pen Input  POS Terminals (Point of Sales  Digital Camera  OCR (Optical Character Recognition)  Microphone
  21. 21. INTRODUCTION TO COMPUTERSCPU – Central Processing UnitData which is entered in the computer is processed in a componentof the system unit called Microprocessor.The CPU consist of ALU (Arthematic & Logical Section which isused for computations, CU (Control Unit for monitoring the sequenceof instructions or programs and controlling the other devicesconnected to the computer.The CPU also consist of MU (Memory Unit) which is used to storedata as well as the results given by the computer. The memory unitis classified into two types:RAM (Random Access Memory) Volatile Memory Data is lost when the lost is switched off.ROM (Read Only Memory) Permanent Memory BIOS (Basic Input Output System) CMOS (Complementary Metal Oxide Semiconductor)
  22. 22. INTRODUCTION TO COMPUTERSOutput Devices Output devices show you the results of processing data  VDU (Visual Display Unit) or CRT (Cathode Ray Tube) or Monitor  LCD  Sound System  Printer  Impact Printers  Dot Matrix  Non-Impact Printers  Laser  Inkjet / Bubble Jet  Computer Output Microfilm(Com) Devices  Plotters  LCD Projectors  Communication Device  Modems  ISDN  Broadband Services (Cable Modems)
  23. 23. INTRODUCTION TO COMPUTERSData RepresentationComputer understands only one language i.e. 8 Bits = 1 Bytemachine language. It is made up of BinaryDigits (0 & 1). 1024 Bytes = 1 KB 1024 KB = 1 MBThe computer stores data in form of BinaryDigits, each digit is known as Bit. Each 1024 MB = 1 GBcharacter stored in computer is a combinationof 8 Bits (see the table below for example) 1024 GB = 1 TB ASCII American Standard Code for Information Interchange
  24. 24. INTRODUCTION TO COMPUTERSStorage DevicesThe device on which is stored permanently,which can be used as future reference.Storage devices are Input / Output devices.The devices are:Magnetic TapesMagnetic Disk Floppy Disk Hard DiskOptical Storage device CD DVD (Digital Versatile Disk)Flash MemoryMemory Card
  25. 25. INTRODUCTION TO COMPUTERSDefinition of Software Instructions and associated data, stored in electronic format, that direct the computer to accomplish a task.
  26. 26. INTRODUCTION TO COMPUTERS Software SOFTWARE Classification of Software System ApplicationHardware cannot work without a Software. Systemsoftware is used by the computer to interact withhardware. Application Software (e.g. MS-Office) cannotbe executed without the installation of system software.An operating system is system software.
  27. 27. INTRODUCTION TO COMPUTERS Components of OSSystem Software File Manager Stores information on various secondary An Operating System (OS) is the storage devices e.g. FDD, HDD…. etc master controller within a computer. Process Manager EX: Windows, MacOS, DOS (Disk To share several programs / processes Operating System), UNIX, Linux to run at the same time the operating An operating system interacts with: system has to share  All hardware installed in or connected to out microprocessor time. a computer system. Device Manager  All software installed or running from a The device manager handles storage device on a computer system. communication between the peripherals and the microprocessor. Memory Manager Various programs are allocated memory in such a manner that no clash occurs.
  28. 28. INTRODUCTION TO COMPUTERSSystem Software Types of Operating System  CUI (Character User Interface) Based Operating System  GUI (Graphics User Interface) Based Operating System  Single Task Operating System  Multitasking Operating System  Single User Operating System  Multi User Operating System
  29. 29. INTRODUCTION TO COMPUTERS System Software - OS DOS (Disk Operating System)  Developed by IBM Windows 95/98/XP/VISTA  GUI Windows NT  Multiuser  Multitasking  Networking  Available in different languages Windows 2000  Windows NT 5.0 – Windows 2000  Provided more Security  Available in different local languages. UNIX  Developed by Bell Labs in 1969 – Dennis Ritchie & Ken Thompson rewrote in C language  CUI  UNIX interface is called as Shell
  30. 30. INTRODUCTION TO COMPUTERS System Software - OS LINUX  Alternate to UNIX  GUI  Created by Linus Torvalds – University of Helsinki – 1991.  Vendors are Red Hat, Caldera Systems, Mandarake … etc. SOLARIS  Sun Micro Systems deleoped in 1991  Features of UNIX  LINUX & Java are also Compatible MAC Operating System  Introduced in 1983 by Apple  GUI  Used in Creative Works
  31. 31. INTRODUCTION TO COMPUTERSApplication Software Accomplishes specific tasks for users. Application Software is further Enables a computer to become a Classified into: multi-purpose machine. 1) Propriety Produce  Create flow charts 2) Off the Shelf worksheets and and graphic reports. organizers. Automate record  Communicate keeping like worldwide. attendance and grades.
  32. 32. INTRODUCTION TO COMPUTERSPersonal Operating Software Word Processor Spreadsheet Presentation Financial Management ERP (Enterprise Resource Planning)  Raw Material Planning  Checking Stock & Inventory  Production & Planning  Finished Goods Planning  Sales  Delivery