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  1. 1. Software Basics System and Application Software CIS 110 Intro to Computing
  2. 2. Software Topics <ul><li>Processing with Programs </li></ul><ul><li>Software Applications: Tools for Users </li></ul><ul><li>System Software: The Hardware-Software Connection </li></ul><ul><li>The User Interface: The Human-Machine Connection </li></ul>
  3. 3. Processing with Programs <ul><li>Software programs are: </li></ul><ul><li>Stored in memory </li></ul><ul><li>Instructions that tell the computer what to do (encoded in binary). </li></ul><ul><li>Designed to solve problems </li></ul>
  4. 4. A Fast, Stupid Machine <ul><li>Computers: </li></ul><ul><li>Perform arithmetic and comparisons capabilities </li></ul><ul><li>Follow precise instructions to perform an operation </li></ul><ul><li>Execute instructions quickly and accurately -- but have absolutely NO “common sense” </li></ul>
  5. 5. A Fast, Stupid Machine <ul><li>Programmers begin with an algorithm </li></ul><ul><li>An algorithm is: </li></ul><ul><ul><li>A set of step-by-step instructions for accomplishing a task (solving a problem) </li></ul></ul><ul><li>Usually begins written in a natural language, e.g., English – computer cannot understand </li></ul><ul><li>Algorithms are translated into the vocabulary of a programming language </li></ul>
  6. 6. The Language of Computers <ul><li>Machine Language -- numeric codes to represent instructions as well as data </li></ul><ul><li>High-level language falls between machine language and natural human language </li></ul><ul><li>“ Compiler” translates high-level language written by programmer into Machine language. </li></ul>
  7. 7. Application Software: Tools for Users <ul><li>Software applications include: </li></ul><ul><li>Consumer Applications </li></ul><ul><li>Integrated Software </li></ul><ul><li>Vertical-market </li></ul><ul><li>Custom Software </li></ul>
  8. 8. Consumer Applications <ul><li>Consumer software differs from other types (music CDs, videos, etc.) based on: </li></ul><ul><ul><li>Documentation </li></ul></ul><ul><ul><li>Upgrade options </li></ul></ul><ul><ul><li>Compatibility </li></ul></ul><ul><ul><li>Warranty </li></ul></ul><ul><ul><li>Extent of ownership/license </li></ul></ul>
  9. 9. Documentation <ul><li>Documentation includes: </li></ul><ul><ul><li>Printed tutorial and reference manuals that explain how to use the software </li></ul></ul><ul><ul><li>On-line manuals and help screens which offer immediate help to the user </li></ul></ul>
  10. 10. <ul><li>Upgrades allow you to pay a smaller fee to get the latest software version </li></ul><ul><li>Newer releases usually have additional features and fewer bugs (hopefully). </li></ul><ul><li>Companies do this to compete, plus they like a reliable revenue stream year after year. </li></ul>Upgrades
  11. 11. Compatibility <ul><li>Compatibility allows software to function properly with the hardware, operating system, and peripherals </li></ul><ul><li>Programs written for one type of computer system may not work on another – must match the machine language of the CPU chip. </li></ul>
  12. 12. Licensing <ul><li>Licensing agreements limit your right to: </li></ul><ul><ul><li>Make copies of software disks </li></ul></ul><ul><ul><li>install software on hard drives </li></ul></ul><ul><ul><li>transfer information to other users </li></ul></ul><ul><li>Commercial software is copyrighted so it can’t be legally duplicated for distribution to others. </li></ul>
  13. 13. Licensing <ul><li>Other Kinds of Licensing : </li></ul><ul><ul><li>Public Domain free, author gives up rights </li></ul></ul><ul><ul><li>Freeware free to use but author retains rights </li></ul></ul><ul><ul><li>Shareware freely copied but only for trial , must pay if you keep. also crippleware, nagware </li></ul></ul><ul><li>“ Open Source” Movement ex. Linux </li></ul><ul><ul><li>Source code as well as finished programs </li></ul></ul><ul><ul><li>Free to use, modify, but must pass on w/ GPL. Companies may only profit from sales of media & installation, training and support services </li></ul></ul>
  14. 14. Distribution <ul><li>Software is also sold through: </li></ul><ul><ul><li>“brick and mortar” retail stores </li></ul></ul><ul><ul><li>mail-order catalogs and web sites </li></ul></ul><ul><ul><li>direct download </li></ul></ul><ul><li>Software is often distributed by direct sales for corporations and other large customers. </li></ul>
  15. 15. Integrated Software Apps: Office “Suites” <ul><li>Business software includes most of these modules: </li></ul><ul><ul><li>Word processing </li></ul></ul><ul><ul><li>Database </li></ul></ul><ul><ul><li>Spreadsheet </li></ul></ul><ul><ul><li>Graphics or Desktop Publishing </li></ul></ul><ul><li>Modules also available individually. </li></ul>
  16. 16. Integrated Software: Advantages <ul><li>Costs less than buying the applications individually. </li></ul><ul><li>Data is easily transferred between modules. </li></ul><ul><li>Commands used in each module are usually the same. </li></ul><ul><li>Seamless integration is the goal. </li></ul>
  17. 17. Vertical-Market and Custom Software <ul><li>Job/Industry-specific software: </li></ul><ul><ul><li>Hospital administration </li></ul></ul><ul><ul><li>Restaurants </li></ul></ul><ul><ul><li>Manufacturing </li></ul></ul><ul><li>Large companies often require customized software for their special needs. </li></ul>
  18. 18. System Software: The Hardware-Software Connection <ul><li>System software is a class of software that includes: </li></ul><ul><ul><li>The operating system </li></ul></ul><ul><ul><li>Device Drivers </li></ul></ul><ul><ul><li>Utility programs </li></ul></ul><ul><li>Purpose is supporting the operation of the computer itself. </li></ul>
  19. 19. Utility Programs <ul><li>Examples: </li></ul><ul><li>Anti-Virus </li></ul><ul><li>Firewall </li></ul><ul><li>Backup </li></ul><ul><li>Disk Utilities </li></ul>These address other machine-oriented issues that are not handled by Operating System
  20. 20. What the Operating System Does <ul><li>At the simplest level, the Operating System </li></ul><ul><ul><li>Manages physical resources (hardware). </li></ul></ul><ul><ul><li>Provides the essentials of a user interface. </li></ul></ul><ul><ul><li>Supplies services to other programs. </li></ul></ul>
  21. 21. What the Operating System Does -- Details <ul><li>The operating system controls: </li></ul><ul><ul><li>Communication with peripherals </li></ul></ul><ul><ul><li>Coordination of concurrent processing </li></ul></ul><ul><ul><li>Memory management </li></ul></ul><ul><ul><li>Monitoring of resources and security </li></ul></ul><ul><ul><li>Management of programs and data </li></ul></ul><ul><ul><li>Coordinating network communications </li></ul></ul>
  22. 22. Where the Operating System Lives <ul><li>Most computers store the OS on disk. </li></ul><ul><li>It must be loaded into main memory (RAM) to run. The BIOS does this when the machine “boots”. </li></ul><ul><li>Some special purpose computers (embedded systems) run it directly from ROM. </li></ul>
  23. 23. Device Drivers <ul><li>Special programs that help the OS understand & control special hardware devices. </li></ul><ul><li>Written by H/W and OS manufacturers </li></ul><ul><li>Ex: drivers for </li></ul><ul><ul><li>Video card -- Network Adapter </li></ul></ul><ul><ul><li>Sound card -- Printer </li></ul></ul>
  24. 24. The User Interface: The Human-Machine Connection <ul><li>The user interface is what the user sees on the screen and how he interacts with it. </li></ul><ul><li>Two major user interface types: </li></ul><ul><ul><li>Character-based “command line” </li></ul></ul><ul><ul><li>Graphical User Interface “GUI” with graphical windows, icons, mouse </li></ul></ul>
  25. 25. A Character-Based Interface: MS-DOS or the Windows “Command Prompt” <ul><li>The user interacts with the OS using commands composed of </li></ul><ul><ul><li>letters </li></ul></ul><ul><ul><li>numbers </li></ul></ul><ul><ul><li>symbols </li></ul></ul>
  26. 26. DOS Command Line: dir Command
  27. 27. DOS Text Mode “GUI” Some later DOS programs worked somewhat like a GUI.
  28. 28. Graphical User Interfaces: Apple Macintosh <ul><li>First commercially successful operating system in which the user interacts with the computer by using a pointing device (e.g. a mouse) and a graphical display full time. </li></ul><ul><li>Mid 1980’s. </li></ul>
  29. 29. Original Apple Macintosh
  30. 30. Current Mac OS X
  31. 31. Graphical User Interfaces: Microsoft Windows <ul><li>Windows 95/98/Me and XP are similar in many ways to the Mac OS. </li></ul><ul><li>Several versions of Windows exist for business and home users. </li></ul><ul><li>Windows has largest share of the desktop market. </li></ul>
  32. 32. Windows 1.0 More or less a bad joke.
  33. 33. Windows 3.0 First version to be a clear success in early 1990s.
  34. 34. Why GUIs Won <ul><li>W indows, I cons, M enus, and P ointing devices </li></ul><ul><li>They’re intuitive </li></ul><ul><li>They’re consistent </li></ul><ul><li>They’re forgiving </li></ul><ul><li>They’re protective </li></ul><ul><li>They’re flexible </li></ul>
  35. 35. Multiple User Operating Systems: UNIX and Linux <ul><li>UNIX was developed at Bell Labs before personal computers were available </li></ul><ul><li>Linux was created by Linus Torvalds and continues to be a work-in-progress </li></ul><ul><ul><li>Linux is free for anyone to use or improve </li></ul></ul>
  36. 36. <ul><li>UNIX remains a dominant Internet operating system for Internet servers. </li></ul><ul><li>These systems allow a timesharing computer to communicate with several other computers or terminals at once. </li></ul><ul><li>Linux is a free “open source” based on the MINIX OS (UNIX Clone). </li></ul><ul><li>Both command-line and GUIs available. </li></ul>Multi-User Operating Systems: UNIX and Linux
  37. 37. A Windows-like Linux GUI -- KDE
  38. 38. O/S Wars <ul><li>MS-DOS versus DR-DOS </li></ul><ul><li>IBM OS/2 versus MS Windows </li></ul><ul><li>Windows versus Macintosh OS Pirates of Silicon Valley </li></ul><ul><li>MS versus Novell Netware </li></ul><ul><li>Linux versus Windows – on the server </li></ul><ul><li>Linux vs Windows – on the desktop? </li></ul>
  39. 39. File System Management <ul><li>DOS stands for Disk Operating System </li></ul><ul><li>With transition from tape to disks, a method for organizing large numbers of data files was needed. </li></ul><ul><li>Files are grouped into a hierarchy of directories (almost all OSes do this). </li></ul><ul><li>GUIs represent these visually as nested folders. </li></ul>
  40. 40. Directories / Folders In DOS/Windows each drive has own root. Files are located by path such as c:Documents and SettingsUser1My Documents eport.doc
  41. 41. Software Issues <ul><li>Piracy </li></ul><ul><li>Look-and-Feel lawsuits </li></ul><ul><li>Software patents </li></ul><ul><li>DMCA </li></ul>
  42. 42. Buzzwords <ul><li>“ Killer App” - killer application </li></ul><ul><li>New program or software category that “everyone” (business or home users) wants/needs. </li></ul><ul><li>Marketing people want to know the next bandwagon to jump on, to get ahead of competition. </li></ul><ul><li>“ Killer apps” can drive hardware sales. </li></ul>
  43. 43. BSOD – “Blue Screen of Death”