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									COMPUTER SOFTWARE



 EDIT Module 1: Introduction to
    Information Technology
Think of a computer as a robot.

What do you want it to do?
 We Want a Computer To:
1. Read input data from source documents or
   secondary storage.
2. Process the data.
3. Display the results.
4. Print the results.
5. Store the results.
6. Transmit the results.
7. Protect itself and the data.
8. Keep track of things that it is doing to restart.
9. Count things to reflect performance.
10. Do multiple things at the same time.
 For the computer to be able to
 perform all these requires the
  user to instruct the computer
software to control the machine
    Why is this topic important
 Hardware is the engine and software is the
  gas that makes it run.
 To understand software concepts is to
  understand how real work gets done on
  computer-based systems within a business.
 To understand software is to appreciate the
  specific details that must be addressed for a
  new computer-based application to be
  implemented.
           Important Topics
   Major categories of software.
   The importance of operating systems and related
    systems software.
   The increasing importance of application
    packages.
   Challenges to implement application packages.
   The evolution of programming languages and the
    reason for so many languages.
      Computer Software
The detailed instructions that control
the operation of a computer system.

   Provide tools to people.
   Intermediary between people and data.
   Manage the computer resources.
   Selecting appropriate software for an
    enterprise is a key management decision.
     Overview of Computer Software
                                 Computer
                                  Software




           Application                               System
            Software                                 Software




General-                 Application-     System                  System
Purpose                   Specific      Management              Development
Programs                  Programs       Programs                Programs
     Trends in Computer Software

  First         Second        Third       Fourth           Fifth
Generation     Generation   Generation   Generation      Generation
 Trend: Toward Easy-to-Use Multipurpose Network-Enabled Application
             Packages for Productivity and Collaboration

                                                            Natural &
                                                         Object-Oriented
                                         DBMS
                                                            Languages
User-Written   Packaged     Operating    Fourth-
                                                           Multipurpose
 Programs       Programs     Systems      Generation
                                                         Graphic- Interface
Machine        Symbolic     High-Level    Languages
                                                         Network-enabled
 Languages      Languages    Languages   Microcomputer
                                                          Expert-Assisted
                                          Packages
                                                             Packages

Trend: Toward Visual or Conversational Programming Languages and
Tools
         Application Software:
          End User Applications
1) General Purpose Application Programs
   Software Suites – Microsoft Office
    – Word Processing - Word / Works / Claris
    – Spreadsheet – Excel / FoxPro / Lotus
    – Database Managers - Access / Dbase/Sybase
   Web Browsers – Internet Explorer / Netscape
   Electronic Mail – MS Outlook / Express /
    Eudora
   Presentation Graphics – Power Point / Flash
          Application Software:
           End User Applications

2) Application-Specific Programs
   Application Software Packages support
    managerial and operational uses:
    –   Accounting
    –   Transaction Processing
    –   Customer Relationship Management
    –   Electronic Commerce
         System Software:
 Computer System Management

1) System Management Programs
• Operating System
  - Resource Management
  - File Management
  - Task Management
• Network Management Programs
• Database Management Systems
• System Utilities
           System Software:
 Computer System Management

2) System Development Programs
• Programming Language
  - BASIC / C++ / COBOL / JAVA/TURBO-PASCAL
• Programming Translators
  - Assemblers – translates assembler language
  - Compilers – translates high level language [translate
    the program (source code) into machine code (object code), then
    execute the object code.]
        Programming Languages

Machine Languages     High Level Languages Markup Languages
Use binary coded      Use brief statements Use embedded
instructions                               control codes
      1001 1001         Compute X = Y + Z     <H1>First heading</H>
      1100 1101                               <!ELEMENT Product
                                              (#Item | manuf)>
Assembler Languages Fourth Generation      Object-Oriented
Use symbolic coded Languages               Languages
instructions        Use natural statements Define objects that
                                             contain data and actions
       LOD Y           SUM THE FOLLOWING
                       NUMBERS                  Document.write
       ADD Z                                    (“Hi There”)
                                   Operating Systems
       In short:                    – Five basic functions:
                                       »   User interface
                                       »   Resource Management
   Software                           »   File Management
    – Application vs. System           »   Task Management
   Application Software               »   Utilities for support
                                           services
    – General purpose
      applications for end         Programming
      users                         Languages
   System Software                 – Five major levels:
                                       »   Machine language
    – Manage hardware,
                                       »   Assembler language
      software, network, data
                                       »   High-level language
      resources
                                       »   Fourth-Generation
                                       »   Object-Oriented
           Systems Software
   Definition:
    – All programs related to coordinating
      computer operations
   Components
    – Operating System
    – Utility programs
    – Program language translators
            Operating System
            Hidden Software
   Definition – provides access to all resources
   Kernel
    – Manages the operating system
    – Memory resident
    – Loads set of programs that lies between applications
      software and the hardware
    – Fundamental software that controls non-resident portions of
      the OS as needed
   Booting – Loads the kernel into memory
         Operating System
A software program that acts as an intermediary
between a user of a computer and the computer
hardware.

Exist because it is a reasonable way to solve the
problem of creating a usable computer by better
managing the computer resources.

The basis for standardization of application
software. (the platform)
 Functions of an Operating System
                         User
                       Interface




                                                Utilities
 Resource       Task            File (Data)
                                               and Other
Management   Management        Management
                                               Functions


Use of       Managing the     Managing        Sort, Merge,
hardware     accomplishment   Data and        Performance,
resources    of tasks         Program Files   etc.
               Functions of OS
   Manage the computer’s resources
    –   CPU
    –   Memory
    –   Disk drives
    –   Printers
   Establish a user interface
   Execute and provide services for applications
    software
   Carries out all input and output operation
 Operating System Functions
Multiprogramming - executing two or more
programs concurrently using the same computer.

Multiprocessing - executing two or more
instructions simultaneously in a single computer by
using multiple central processing units.

Graphical User Interface (GUI) - part of the
operating system that uses graphic icons to issue
commands and make selections.
                User Interface
   Facilitates communication between the user and
    the operating system

   Two forms
    – Command line
       » Text-based
       » Key commands
       » Examples: MS-DOS, Unix
    – Graphical user interface (GUI)
       » Visual images
       » Menus
       » Examples: Windows, Mac OS, Linux
 Popular Operating Systems
• DOS               UNIX

• Windows .X        Linux
                    OS/2
• Windows NT
                    Mac OS
                    IBM MVS, VM
             OS is Hidden
   User interested in application
    software to make the PC
    useful
   Application software is
    platform specific
   User must be aware of the
    type of OS
   User should be aware of the
    functions of OS
What is the platform of your
          system?
   A common question posed to a
system vendor, manufacturer or even
    the organization utilizing the
             system…..
                  Platform
   Definition:
      Computer hardware and operating
      system software that dictate what other
      software can run


   E.g. Wintel
      Intel-based PC running on
      Microsoft Windows
      Types of OS

        Command line
        Single user PC
Network Operating System (NOS)
    Command-line: MS-DOS




   Command-line interface
   Prompt – system is waiting for you to do
    something
   Key a command
   Not user-friendly
             Single-user PC:
            Microsoft Windows
   Graphical user
    interface
   Eases access to
    the OS
   Most new
    computers come
    with Windows
    already installed
    Network Operating System
             NOS
   Designed to permit computers on a network
    to share resources
   Examples
    – Windows 2000 Server
    – Novell Net Ware
   Provides
    – Data security
    – Troubleshooting
    – Administrative control
              NOS Functions
   Split between client and server computers
   Server
    – File management
   Client
    – Requests to the server
    – Messaging
    – Has own local OS
   Makes the resources appear as if they are
    local to the client’s computer
 Early Days of Windows OS

Operating environment for MS-DOS

Shell – layer added between users
              and DOS
             Windows Today
   Home/consumer market
    – Windows 95
    – Windows 98
    – Windows Millennium Edition (ME)
   Corporate market
    – Windows NT
    – Windows 2000
   Windows XP
   Pocket computers and Internet appliances
    – Windows CE
What are the prominent features
         of Windows?
          Prominent feature of
             Windows: GUI
   On-screen pictures
    – Icons
    – Menus
        » Pull down
        » Pop up
    – Click to activate a
      command or function
   Fast
   Easy
   Intuitive
          Windows 95 and 98
   Self-contained OS
   DOS commands still available
   Start programs by
    – Start button
    – Double clicking the icon
   Task bar permits movement between open
    programs
   Long file names up to 255 characters
   Plug and play
   Object linking and embedding (OLE)
       Windows 98 Additions
   Internet / intranet browsing
   Support for DVD and additional
    multimedia components
   Support for large hard drives
   TV viewer and broadcast ability
   Wizards / Help Assistant
Improved Windows Features
 Backup
 Interfaces with other software
 Networking features
 Security
 Dr. Watson
                Windows

Helps reduce the cost of owning and
maintaining a PC
             Windows ME
           Millennium Edition
Multimedia support -- Windows Media Player 7
   Jukebox
    – Record music CDs as digital files
   Windows Movie Maker
    – Basic video editing
   Windows Image Acquisition
    – Scanner and digital camera
             Windows ME
           Millennium Edition
   Reliability Features
    – System File Protection
    – AutoUpdate
    – System Restore
   Help Center
   Home Network Support
    – Wizard for connecting multiple computers and
      peripherals
    – Multiple users can share a single Internet
      connection
              Windows NT
             New Technology
   Engineered for stability
   Strong security
   Versions
    – NT Workstation
    – NT Server
   Drawbacks
    – Lacks support for older Windows and MS-DOS
      software and hardware
    – Complex to learn and use
    – Requires more memory and processing power
              Windows 2000
   Stability features
   Security features
   Uses simple approach to hardware setup
    from Windows 98
   Versions
    – Windows 2000 Professional for individual users
    – Windows 2000 for network servers
   Was intended for both the corporate and
    home use, replacing Win NT and Win 98
                Windows 2000

   Complex
   Heavy demand for computer resources
   Improvements over windows NT
    –   Maintains user preferences
    –   Self-healing applications software
    –   Supports Windows 98 file structure
    –   Uses plug and play
    –   Provides improved support for laptops
                  Windows XP
   Extends Windows ME and provides a
    more stable environment
   Two categories
    – Network server
      » 3 versions based upon network complexity
    – Desktop computer
      » 2 versions
            Professional Client
            Personal Client
            Windows CE
         Consumer Electronics
Where used
   Embedded systems
    –   Industrial controllers
    –   Robots
    –   Office equipment
    –   Cameras
    –   Telephones
    –   Home entertainment devices
    –   Automobile navigation systems
   Pocket PC
   Internet appliance market
          Windows CE
       Consumer Electronics
Subset of Windows
   Less memory
   Smaller screens
   Little or no file storage
   Provides Internet connectivity
Mac OS
        First
         commercially
         successful GUI
         (1984)

        Served as a
         model to other
         GUI systems
                     UNIX
   Supports
    – Multi-user
    – Time-sharing
 Character-based system
 Command-line interface
 Runs on various processors and many
  types of computers
 Primary OS used on Internet servers
                       LINUX
   UNIX-like OS
   Open-source software
    –   Download it free
    –   Make changes
    –   Distribute copies
    –   Restriction – any changes must be freely
        available to the public
   PC Setup
    – PC comes with Windows installed
    – Install LINUX in a dual-boot configuration
                      LINUX

   Advantages over Windows
    – Extremely stable
    – Internet support
    – Reinstallation is simpler


   Disadvantage
    – Scarcity of applications
           Large Computers
 Used by many people at once
 OS works “behind the scenes” so users
  can share resources (hardware &
  software)
 OS must control
    – Who gets access to resources
    – What keeps the programs from different
      users from getting mixed up with one
      another
           Sharing Memory
   Program must be in memory to be
    executed
   Problems
    – Programs compete for space
    – May have a very large program
    – Memory space for each program must not
      overlap
       Memory Management


   The process of providing separate
    memory space to programs
   Memory Protection keeps one
    program from interfering with another
            Sharing Storage
   Several users need to access the same
    disk pack
    – One wants to write
    – Another wants to read

   OS keeps track of the I/O requests
   OS processes I/O requests in order
    received
           Utility Programs
   Come with System Software
   Handle special needs
   Perform secondary chores
   Do not need to be memory resident
    Functions of Utility programs
   File manager – provide access to lists of stored files
   Backup and Restore – make duplicate copies of
    important files and return the copy to the hard drive if
    needed
   File compression – reduces the amount of disk
    space required by a file
   Disk defragmenter – reorganize files so they are
    stored contiguously on disk providing for faster
    access
   Device drivers – convert operating system
    instructions into commands that are known to a
    specific device
Are all operating systems the same?

      Features and functions.
      Advantages and benefits.


 From Personal Computers to Mainframes?
                Summary
Operating systems are the foundation of a
computer operation.
Operating systems benefits include better resource
utilization, better system performance, gains in cost-
effectiveness and better overall management of the
entire system.

Without operating systems with advanced features
and functions, computing would still be in its very
early stages.

								
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