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Computer Systems

Computer Systems. COMPUTER GENERATIONS. 1. VACUUM TUBES: 1946-1959. COMPUTER GENERATIONS. 1. VACUUM TUBES: 1946-1959 2. TRANSISTORS: 1957-1963. COMPUTER GENERATIONS. 1. VACUUM TUBES: 1946-1959 2. TRANSISTORS: 1957-1963 3. INTEGRATED CIRCUITS: 1964-1979. COMPUTER GENERATIONS.

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Computer Systems

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  1. Computer Systems

  2. COMPUTER GENERATIONS 1. VACUUM TUBES: 1946-1959

  3. COMPUTER GENERATIONS 1. VACUUM TUBES: 1946-1959 2. TRANSISTORS: 1957-1963

  4. COMPUTER GENERATIONS 1. VACUUM TUBES: 1946-1959 2. TRANSISTORS: 1957-1963 3. INTEGRATED CIRCUITS: 1964-1979

  5. COMPUTER GENERATIONS 1. VACUUM TUBES: 1946-1959 2. TRANSISTORS: 1957-1963 3. INTEGRATED CIRCUITS: 1964-1979 4. VERY LARGE-SCALE INTEGRATED (VLSI) CIRCUITS:1980- PRESENT *

  6. SUPERCOMPUTERTERAFLOP:TRILLION CALCULATIONS/SECOND • HIGHLY SOPHISTICATED • COMPLEX COMPUTATIONS • FASTEST CPUs • LARGE SIMULATIONS • STATE-OF-THE-ART COMPONENTS • EXPENSIVE *

  7. MAINFRAME MIPS: Millions of Instructions per second • LARGEST ENTERPRISE COMPUTER • 5O MEGABYTES TO OVER ONE GIGABYTE RAM • COMMERCIAL, SCIENTIFIC, MILITARY APPLICATIONS • MASSIVE DATA • COMPLICATED COMPUTATIONS *

  8. MINICOMPUTER • MIDDLE-RANGE • 10 MEGABYTES TO OVER ONE GIGABYTE RAM • UNIVERSITIES, FACTORIES, LABS • USED AS FRONT-END PROCESSOR FOR MAINFRAME *

  9. MICROCOMPUTER • DESKTOP OR PORTABLE • 64 KILOBYTES TO OVER 128 MEGABYTES RAM • PERSONAL OR BUSINESS COMPUTERS • AFFORDABLE • MANY AVAILABLE COMPONENTS • CAN BE NETWORKED *

  10. LAPTOPS & SMALLER • LAPTOP (OR NOTEBOOK): Briefcase type package, very portable, can be inexpensive, can connect to other computers or networks • HAND-HELD (OR PALMTOP): Sub-miniature, wireless computer. Growing in sophistication and connectivity *

  11. BASIC COMPONENTS OF COMPUTER SYSTEMS • UNDERLYING STRUCTURE • INPUT/OUTPUT • BITS & CODING SCHEMES • ARITHMETIC LOGIC UNIT *

  12. ARITHMETIC/LOGIC UNIT CLOCK ROM RAM PRIMARY (MAIN) MEMORY CENTRAL PROCESSING UNIT (CPU) CONTROL UNIT

  13. PRIMARY STORAGE CPU OUTPUT DEVICES SECONDARY STORAGE INPUT DEVICES BUSES DATA BUS ADDRESS BUS CONTROL BUS

  14. TYPES OF MEMORY • RAM : Random Access Memory • Dynamic: Changes thru processing • Static: Remains constant (power on) • ROM : Read Only Memory (preprogrammed) • PROM: Program can be changed once • EPROM: Erasable thru ultraviolet light • EEPROM: Electrically erasable *

  15. INPUT/OUTPUT • TERMINAL • POINT-OF-SALES TERMINALS • AUTOMATIC TELLER MACHINES • PUNCHED CARDS • MAGNETIC INK CHARACTERRECOGNITION (MICR):Used by banks to process checks *

  16. INPUT/OUTPUT • OPTICAL CHARACTER RECOGNITION: Scanned material translated into computer characters • IMAGING: Forms, documents, photos digitized for computer use • BAR CODE LABEL: Product label information read into computer. Can be used to track inventory *

  17. INPUT/OUTPUT • COMPUTER OUTPUT MICROFILM (COM): Computer rapidly generates microfilm documents for archive copies in small space • VOICE RESPONSE UNITS: Computer recognizes, generates verbal messages • MULTIMEDIA: Combines text, graphics, sound still images, animations, video *

  18. HOW CHARACTERS ARE STORED IN COMPUTER MEMORY • BIT: Binary Digit. On/Off, 0/1, Magnetic/Not • BYTE: Group of bits for one character • EBCDIC- Extended Binary Coded Decimal Interchange Code (8 bits per byte) • ASCII- American Standard Code for Information Exchange (7 or 8 bits per byte) • PARITY BIT: extra bit added to each byte to help detect errors *

  19. C: 1100 0011 0 100 0011 1 A: 1100 0001 1 100 0001 0 T: 1110 0011 1 101 0100 1 Note how sum for each byte is an EVEN number * EXAMPLES OF BYTES EBCDIC ASCII (assume even-parity system)

  20. ALU & CONTROL UNIT • ARITHMETIC- LOGIC UNIT: CPU component performs logic and arithmetic operations • CONTROL UNIT: CPU component controls, coordinates other parts of computer system *

  21. COMPUTER FILES • RECORD: Data about a transaction arranged in a set of FIELDS, each holding a datum • FILE: A group of similar records, such as accounts receivable or payroll • DATABASE: The files of an organization, an electronic library *

  22. COMPUTER FILES • SEQUENTIAL ACCESS: A sequence of files arranged in order, say alphabetically. Usually stored on magnetic tape or cartridge • DIRECT ACCESS: Records stored on a DIRECT ACCESS STORAGE DEVICE (DASD). Can move directly to any record *

  23. DIRECT ACCESS STORAGE DEVICE • HARD DISK: Steel platter array for large computer systems • RAID: Redundant array of Inexpensive Disks • FLOPPY DISK: Removable disk for PC *

  24. DISK 1 DISK 2 DISK 3 DISK 4 DISK 5 READ/WRITE HEADS CYLINDER 10: TRACK 10 (TOP AND BOTTOM OF EACH DISK) DISK PACK STORAGE • LARGE SYSTEMS • RELIABLE STORAGE • LARGE AMOUNTS OF DATA • QUICK ACCESS & RETRIEVABLE • TYPICAL: 11 2-SIDED DISKS • CYLINDER: SAME TRACK ALL SURFACES

  25. THE STORED PROGRAM CONCEPT • COMPUTER IS A BINARY SYSTEM • PROGRAM: A set of instructions telling the computer what to do • INSTRUCTION: Individual step or operation in a program • MACHINE LANGUAGE: Translated instruction understood by particular model of computer *

  26. CONTROLLER • LINK FOR INPUT/OUTPUT OR FILE DEVICES: To CPU and memory of large computer systems • HIGHLY SPECIALIZED PROCESSOR: Manages the operation of attached devices to free the CPU from these tasks *

  27. DATA CHANNEL • SPECIALIZED INPUT/OUTPUT PROCESSOR (A COMPUTER):Takes over function of device communication from the CPU • CORRECTS FOR SPEED MISMATCH BETWEEN SLOW PERIPHERAL DEVICES AND VERY FAST CPU *

  28. SYMMETRIC MULTIPROCESSOR • PROCESSORS (CPUs) ARE IDENTICAL, WITH EACH PROCESSOR OPERATING INDEPENDENTLY OF THE OTHERS • USED IN MOST MAINFRAMES AND SOME MIDRANGE MACHINES *

  29. PARALLEL PROCESSOR (PP) • MULTIPLE CPUs INSTALLED AS PART OF A SINGLE COMPUTER SYSTEM:Gives separate piece of program to each of the processors so that work on the program can proceed in parallel on the separate pieces *

  30. MASSIVELY PARALLEL PROCESSOR (MPP) PARALLEL PROCESSING COMPUTER WITH MANY PARALLEL PROCESSORS: • 32 OR MORE: Different CPUs capable of performing different instructions at the same time • 1000 OR MORE: CPUs must all carry out the same instruction at the same time

  31. Computer Software

  32. THE STORED PROGRAM CONCEPT • COMPUTER IS A BINARY SYSTEM • PROGRAM: A set of instructions telling the computer what to do • INSTRUCTION: Individual step or operation in a program • MACHINE LANGUAGE: Translated instruction understood by particular model of computer *

  33. EVOLUTION OF COMPUTER SOFTWARE • FIRST GENERATION: Machine language - binary language designed for particular computer • SECOND GENERATION: Assembly language - substituted mnemonic operation codes and addresses, translated to machine language by assembler *

  34. EVOLUTION OF COMPUTER SOFTWARE • THIRD GENERATION: Procedural language - FORTRAN, COBOL, C - translated to machine language by compiler or interpreter. Example: COBOL • FOURTH GENERATION: Nonprocedural language. Tell what to do, not how to do it, order not important. Translate to machine language by compiler or interpreter. Example: FOCUS *

  35. KEY TYPES OF SOFTWARE • APPLICATION SOFTWARE: Programs written to accomplish particular tasks for computer users • SUPPORT SOFTWARE: Programs that support application software in producing needed output. Does not directly produce output needed by users *

  36. APPLICATION SOFTWARE • WORD PROCESSING • SPREADSHEETS • DATABASE MANAGEMENT SYSTEMS • PRESENTATION GRAPHICS *

  37. APPLICATION SOFTWARE • WORLD WIDE WEB BROWSERS • ELECTRONIC MAIL, GROUPWARE • DESKTOP PUBLISHING • APPLICATION SUITES *

  38. SUPPORT SOFTWARE • OPERATING SYSTEMS:Helps maximize work done, eases workload of users • JOB CONTROL LANGUAGE:Allows users to communicate with operating systems • MULTIPROGRAMMING:Large computers can run multiple programs simultaneously. Time-driven approach is time-sharing *

  39. SUPPORT SOFTWARE • MULTITASKING:Allows small computers to work on several programs interactively • VIRTUAL MEMORY:Allows computer to run portions of a large program as required, saving use of main memory • MULTIPROCESSING:Multiple CPUs divide workload, increases efficiency *

  40. SOURCES OF OPERATING SYSTEMS • PROPRIETARY: Written for particular computer class or system. Examples: Windows 98, Windows 2000 • OPEN SYSTEM: Not tied to specific platform. Examples: UNIX, Linux • NETWORK OPERATING SYSTEM (NOS):Manages network resources, local area networks *

  41. GRAPHICAL USER INTERFACE (GUI) • MOUSE: A standard pointing device • ICON: Graphic or label on screen associated with task or operation • 32-BIT OPERATING SYSTEM: Operating system handles 32 bits at a time • CLICKING MOUSE ON ICON INITIATES TASK *

  42. OBJECT-ORIENTED PROGRAMMING (OOP) • COMPUTER PROGRAMMING BASED ON CREATING, USING SET OF OBJECTS: Object combines data and methods (or chunks of programs) • EXAMPLES: C++, Smalltalk, Java *

  43. OTHER LANGUAGES • NATURAL LANGUAGES: User types in or speaks English, computer evolves program • HYPERTEXT MARKUP LANGUAGE (HTML):Code used to develop World Wide Web (WWW) pages and sites • eXtensible Markup Language (XML):Used for data exchange on WWW *

  44. DATABASE MANAGEMENT SYSTEM (DBMS) • SUPPORT SOFTWARE USED TO CREATE, MANAGE, AND PROTECT ORGANIZATIONAL DATA • DBMS: Software that manages a database, works with operating system to store and modify data and to make data accessible in authorized ways *

  45. TYPES OF DBMSs • HIERARCHICAL: Data arranged in a top-down, organization chart fashion • NETWORK: Data arranged like cities on a highway systems, often with multiple paths between pieces of data • RELATIONAL: Data arranged into simple tables, and records are related by storing common data in each of the associated tables *

  46. FILING METHODS • INDEXED SEQUENTIAL ACCESS METHOD (ISAM) : • EACH RECORD IDENTIFIED BY KEY • GROUPED IN BLOCKS AND CYLINDERS • KEYS IN INDEX • VIRTUAL STORAGE ACCESS METHOD (VSAM) : • MEMORY DIVIDED INTO AREAS & INTERVALS • DYNAMIC FILE SPACE VSAM WIDELY USED FOR RELATIONAL DATABASES • DIRECT FILE ACCESS METHOD *

  47. COMPONENTS OF DBMS: • DATA DEFINITION LANGUAGE: Defines data elements in database • DATA MANIPULATION LANGUAGE: Manipulates data for applications • DATA DICTIONARY/DIRECTORY: Formal definitions of all variables in database, controls variety of database contents *

  48. STRUCTURED QUERY LANGUAGE (SQL) EMERGING STANDARD DATA MANIPULATION LANGUAGE FOR RELATIONAL DATABASES *

  49. ADVANTAGES OF RELATIONAL DBMS • NEW DATA ELEMENTS CAN EASILY BE ADDED AS NEW NEEDS ARISE • NEW RELATIONSHIPS CAN BE CREATED AS NEW QUERY/REPORTING NEEDS CHANGE • FEWER DATA CONSISTENCY PROBLEMS DUE TO LESS REDUNDANT DATA STORAGE • MORE “USER FRIENDLY” TOOLS *

  50. COMPUTER-AIDED SOFTWARE ENGINEERING (CASE) • HELPS AUTOMATE SOFTWARE DEVELOPMENT: Used by computer professionals to help automate software development • MAY INCLUDE: • upper-CASE (requirements definition and design) • lower-CASE (code generation) • I-CASE or integrated-CASE *

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