Unit 4: The Basics

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Unit 4 The Basics

• Software components of a computer system

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Types of Software

• 1 Compilers
• 2 Application Software
• 3 System Software

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Objectives

• Explain the relationship of algorithms to
  software
• Describe three fundamental categories of software
  and their relationship
• Discuss the factors that make a computer
  application a useful tool
• Describe the role of the operating system in a
  modern computer system

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• The three major categories of software
• Compilers and other translator programs
• enable programmers to create other software
• Software applications
• serve as productivity tools to help computer
  users solve problems
• System software
• coordinates hardware operations and does
  behind-the-scenes work the computer user seldom
  sees

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1 Compilers
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• The Language of Computers
• Machine Language numeric codes that represent
  data.
• High-level language falls between machine
  language and natural human language
• Compilers translate high-level language into
  machine language
• Natural Languages resemble languages spoken by
  humans

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Linus Torvalds and the Software Nobody Owns

• Linus Torvalds
• Best known as the Linux creator
• The Linux operating system is the best-known
  example of open source software
• Today Linux powers Web servers, film and
  animation workstations, scientific
  supercomputers, and a handful of handhelds
• Linux is a software that is available in an
  uncompiled format

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2 Application Software
Consumer ApplicationsIntegrated
ApplicationsVertical Marketing and Custom
Software
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Application Software

• Consumer Applications - features
• Many software companies have replaced their
  printed documentation with
• Tutorials
• Reference materials
• Help files
• On-line help
• Upgrading users can upgrade a program to the new
  version by paying an upgrade fee to the software
  manufacturer
• Newer releases often have additional features and
  fewer bugs

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Application Software

• Consumer Applications - features
• Compatibility
• Allows software to function properly with the
  hardware, operating system, and peripherals
• Programs written for one type of computer system
  may not work on another
• Disclaimers
• Software manufacturers limit their liability for
  software problems by selling software as is (an
  agreement in the EULA)

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Integrated Applications and Suites Software
Bundles

• Integrated software packages
• Include several applications designed to work
  well together
• Enable automatic transfer of data between modules
• Cost less than buying the applications
  individually
• Use the same type of commands in each module

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Integrated Applications and Suites Software
Bundles

• Popular integrated packages, like AppleWorks and
  Microsoft Works, generally include
• Word processing
• Database
• Spreadsheet
• Graphics
• Telecommunication
• Personal information management
  (PIM) modules

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Integrated Applications and Suites Software
Bundles

• Application suites bundles containing several
  full application programs that are also sold as
  separate programs
• The core applications of the Microsoft Office
  System (the most popular application suite)
  include
• Word (a word processing program)
• Excel (a spreadsheet program)
• PowerPoint (a presentation graphics program)
• Access (a database program)
• Outlook (an email/personal-information management
  program)

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Integrated Applications and Suites Software
Bundles

• Vertical-Market and Custom Software
• Tends to cost far more thanmass-market
  applications
• Job-specific software
• Medical billings
• Library cataloging
• Legal reference software
• Restaurant management
• Single-client software needs

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3 System Software
Utility ProgramsDriversOperating Systems
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System Software Operating Systems

• Operating system functions
• Communicating with peripherals
• Coordinating concurrent processing of jobs
• Memory management
• Resource monitoring, accounting, and security
• Program and data management
• Coordinating network communications

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System Software The operating System

• Where the Operating System Lives
• Some computers store their operating system in
  ROM
• Others include only part of it in ROM
• The remainder of the operating system is loaded
  into memory in a process called booting, which
  occurs when you turn on the computer

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The Purpose of a Operating System

• The OS Most important piece of software in any
  computer
• The OS is a collection of programs that control
  the hardware that makes up the Computer system,
  e.g.
• Getting characters from the keyboard
• Sending output to a printer
• Reading and updating files on hard disk
• Loading programs and data into RAM

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The Origins of Operating Systems

• Pre 1960 No such thing.
• Programmers had to write their own programs to
• Load data
• Get characters from the keyboard
• Output characters to a printer etc etc.
• However, programmers soon realised
• Most programs contained blocks of instructions
  that were exactly the same and commonly required,
  eg for inputting data and outputting results.

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The Origins of Operating Systems

• This commonly used, reusable code was grouped
  into a library and made available to all
  programmers.
• When a programmer wanted a program to input or
  output
• The required block of code would be called with a
  one line instruction
• What other advantages can a library offer a
  programmer/developer?
• In the 60s magnetic storage was becoming more
  widely used, requiring even more programs to
  manage directories etc.

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What OSs are like now

• HUGE
• Reasons for being so big
• Graphical User Interface (GUI), hugely resource
  hungry compared to text based display.
• Constant stream of new peripherals mean new
  drivers and access utilities and program
• More and more bloatware is being provided free
  with OSs

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System Software Operating Systems

• Multiple User Operating Systems UNIX and Linux
• UNIX was developed at Bell Labs before personal
  computers were available
• Linux was created by Linus Torvalds and continues
  to be a work-in-progress
• Allow a timesharing computer to communicate with
  several other computers or terminals at once

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System Software Utility Programs

• Utility Programs Function
• Serve as tools for doing system maintenance and
  repairs that arent automatically handled by the
  operating system
• Make it easier for users to
• Copy files between storage devices
• Repair damaged data files
• Translate files so that different programs can
  read them
• Guard against viruses and other potentially
  harmful programs (as described in the chapter on
  computer security and risks)
• Compress files so they take up less disk space
• Perform other important, if unexciting, tasks

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System Software Utility Programs

• Symantec Norton Utilities is a popular utility
  package that includes software tools for
  recovering damaged files, repairing damaged
  disks, and improving disk performance

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System Software Drivers

• Device drivers
• Small programs that enable I/O deviceskeyboard,
  mouse, printer, and othersto communicate with
  the computer
• Included with the operating system or bundled
  with peripherals

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A word about user Interfaces
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The User Interface The HumanMachine Connection

• Most of the time it works behind the scenes
• Interacting with the operating system, like
  interacting with an application, can be intuitive
  or challenging and it depends on something called
  the user interface

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The User Interface The HumanMachine Connection

• Features include
• Command-line interface (commands are typed)
• Menu-driven interface (commands are chosen from
  on-screen lists)

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The User Interface The HumanMachine Connection

• Graphical User Interfaces
• Mac OS
• This is a disk operating system in which the user
  interacts with the computer by using a pointing
  device (e.g., a mouse)

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The User Interface The HumanMachine Connection

• Microsoft Windows
• Originally, Microsoft Windows (commonly called
  Windows) was a type of program, known as a shell,
  which put a graphical face on MS-DOS
• With the introduction of Windows 95 in 1995,
  Microsoft began transitioning Windows from an
  operating system shell into a full operating
  system that seldom showed its MS-DOS roots
• The latest Windows versions have no ties at all
  to the DOS past
• The Windows XP GUI

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The User Interface The HumanMachine Connection

• File Management Wheres My Stuff?
• Files can be scattered all over the system, which
  often makes data management difficult
• One solution to this problem is to organize data
  files logically
• Both Windows and the Mac support the notion of
  common system folders with self-explanatory
  names
• My Documents (Documents)
• My Pictures (Pictures)
• My Music (Music)

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The User Interface The HumanMachine Connection

• File Management Wheres My Stuff?
• File-Management Utilities
• View, rename, copy, move, and delete files and
  folders
• Hierarchies help with organization
• Help with locating a file
• Get size, file type, and last modification date
• Managing Files from Applications
• Operations Open, Save As, Save and Close
• Defragmentation

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The User Interface The HumanMachine Connection

• Linux is free for anyone to use or improve
• UNIX remains the dominant operating system for
  Internet servers
• Some form of UNIX is available for personal
  computers, workstations, servers, mainframes, and
  supercomputers

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Inventing the Future Tomorrows Evolving
Applications and Interfaces

• WIMP (windows, icons, menus, and pointing
  devices) interface
• Easier to learn and use than earlier
  character-based interfaces
• SILK interface incorporates many important
  emerging user interface software technologies
• Speech and language
• Image
• Knowledge

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Lesson Summary

• What is Software?
• Compilers and other translator programs, which
  enable programmers to create other software
• Software applications, which serve as
  productivity tools to help computer users solve
  problems
• System software, which coordinates hardware
  operations and does behind-the-scenes work the
  computer user seldom sees