Tomorrow s Technology and You 8 th Edition

Tomorrow’s Technology and You 8 th Edition © 2008 Prentice-Hall, Inc. Slide 1

Chapter 4 Software Basics: The Ghost in the Machine © 2008 Prentice-Hall, Inc. Slide 2

Chapter 4 Objectives ü Describe three fundamental categories of software and their relationship. ü Explain the relationship of algorithms to software. ü Discuss the factors that make a computer application a useful tool. ü Describe the role of the operating system in a modern computer system. © 2008 Prentice-Hall, Inc. Slide 3

Chapter 4 Objectives ü Describe how file systems are organized. ü Outline the evolution of user interfaces from early machine- language programming to futuristic virtual-reality interfaces. ü Explain why unauthorized copying of software is against the law. © 2008 Prentice-Hall, Inc. Slide 4

Chapter 4 Linus Torvalds and the Software Nobody Owns ü Linus Torvalds Ø Best known as the Linux creator q q The Linux operating system is the bestknown example of open source software. Today Linux powers Web servers, film and animation workstations, scientific supercomputers, and a handful of handhelds. © 2008 Prentice-Hall, Inc. Slide 5

Chapter 4 Linus Torvalds and the Software Nobody Owns ü The three major categories of software: Ø Compilers and other translator programs: enable programmers to create other software Ø Software applications: serve as productivity tools to help computer users solve problems Ø System software: coordinates hardware operations and does behind-the-scenes work the computer user seldom sees ü OS vs. Application software © 2008 Prentice-Hall, Inc. Slide 6

Chapter 4 Processing with Programs ü Food for Thought Ø The hardware in a computer system is equipped to produce whatever output a user requests. © 2008 Prentice-Hall, Inc. Slide 7

Chapter 4 Processing with Programs ü A Fast, Stupid Machine Ø Programmers begin with an algorithm: a set of step-by-step instructions written in a natural language, e. g. , English. Ø The steps are often ambiguous, error-prone generalities. Ø The steps are translated into the vocabulary of a programming language. © 2008 Prentice-Hall, Inc. Slide 8

Chapter 4 Processing with Programs ü The Language of Computers Machine Language: numeric codes that represent data Ø High-level language: falls between machine language and natural human language Ø q Ø The programmer, like the poet, works only slightly removed from pure thoughtstuff. He builds castles in the air, creating by exertion of the imagination. Yet the program construct, unlike the poet’s words, is real in the sense that it moves and works, producing visible outputs separate from the construct itself. —Frederick P. Brooks, Jr. , in The Mythical Man Month Compilers translate high-level language into machine language. Natural Languages: resemble languages spoken by humans © 2008 Prentice-Hall, Inc. Slide 9

Chapter 4 Software Applications: Tools for Users ü Consumer Applications Ø Many software companies have replaced their printed documentation with: q q Ø 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. q Newer releases often have additional features and fewer bugs. © 2008 Prentice-Hall, Inc. Slide 10

Chapter 4 Software Applications: Tools for Users Ø Compatibility It allows software to function properly with the hardware, operating system, and peripherals. q Programs written for one type of computer system may not work on another. q Ø Disclaimers q Software manufacturers limit their liability for software problems by selling software “as is. ” © 2008 Prentice-Hall, Inc. Slide 11

Chapter 4 Software Applications: Tools for Users Ø Licensing: Commercial software is copyrighted so it can’t be legally duplicated for distribution to others. q q Ø Software license Volume licenses Distribution: Software is distributed via: q q q Direct sale Retail stores Mail-order catalogs Web sites Not all software is copyrighted. § Public domain software § Shareware © 2008 Prentice-Hall, Inc. Slide 12

Chapter 4 Web Applications Ø Web applications fall into several categories: q q q Some simple Web applications perform simple data-processing tasks that could also be performed by traditional programs running on stand-alone PCs. Most Web applications take advantage of the Web’s connectivity. Many Web applications leverage the Web’s strength as a huge repository of information. Some Web applications support online business transactions. News-oriented Web applications provide up-to-the-minute reports on a myriad of subjects. Other Web applications support a more traditional form of information broadcasting. © 2008 Prentice-Hall, Inc. Slide 13

Chapter 4 Integrated Applications and Suites: Software Bundles ü Vertical-Market and Custom Software Ø Tends to cost far more than mass-market applications Ø Job-specific software: q q q Medical billings Library cataloging Legal reference software Restaurant management Single-client software needs © 2008 Prentice-Hall, Inc. Slide 14

Chapter 4 System Software: The Hardware-Software Connection What the Operating System Does ü System software Ø A class of software that includes the operating system and utility programs, handles these details, and hundreds of other tasks behind the scenes. Originally, operating systems were envisioned as a way to handle one of the most complex input/output operations: communicating with a variety of disk drives. But, the operating system quickly evolved into an all-encompassing bridge between your PC and the software you run on it. —Ron White, in How Computers Work © 2008 Prentice-Hall, Inc. Slide 15

Chapter 4 System Software: The Hardware-Software Connection ü Operating system functions: Ø Supports multitasking Ø Manages virtual memory Ø Maintains file system Ø Responsible for authentication and authorization © 2008 Prentice-Hall, Inc. Slide 16

Chapter 4 System Software: The Hardware-Software Connection Utility Programs and Device Drivers ü Utility programs Ø Serve as tools for doing system maintenance and repairs that aren’t automatically handled by the operating system Ø Make it easier for users to: q q q 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 © 2008 Prentice-Hall, Inc. Slide 17

Chapter 4 System Software: The Hardware-Software Connection Ø Symantec Norton Utilities is a popular utility package that includes software tools for recovering damaged files, repairing damaged disks, and improving disk performance. © 2008 Prentice-Hall, Inc. Slide 18

Chapter 4 System Software: The Hardware-Software Connection ü Device drivers Ø Small programs that enable I/O devices—keyboard, mouse, printer, and others—to communicate with the computer Ø Included with the operating system or bundled with peripherals © 2008 Prentice-Hall, Inc. Slide 19

Chapter 4 System Software: The Hardware-Software Connection üWhere the Operating System Lives Ø Some computers store their operating system in ROM. Ø Others include only part of it in ROM. q The remainder of the operating system is loaded into memory in a process called booting, which occurs when you turn on the computer. © 2008 Prentice-Hall, Inc. Slide 20

Chapter 4 System Software: The Hardware-Software Connection Ø Most of the time the operating system works behind the scenes. Ø Interacting with the operating system, like interacting with an application, can be intuitive or challenging and it depends on something called the user interface. © 2008 Prentice-Hall, Inc. Slide 21

Chapter 4 The User Interface: The Human–Machine Connection User Interface ü The interface defines the look and feel of the computing experience from a human point of view. ü Desktop Operating Systems Ø MS-DOS is a disk operating system in which the user interacts using characters: q q q Letters Numbers Symbols © 2008 Prentice-Hall, Inc. Slide 22

Chapter 4 The User Interface: The Human–Machine Connection Ø Features include: q Command-line interface (commands are typed) q Menu-driven interface (commands are chosen from on-screen lists) © 2008 Prentice-Hall, Inc. Slide 23

Chapter 4 The User Interface: The Human–Machine Connection Ø Graphical User Interfaces (GUI) q q Mac OS was developed by Macintosh in 1984 using GUI. Microsoft Windows is now the most popular operating system. © 2008 Prentice-Hall, Inc. Slide 24

Chapter 4 The User Interface: The Human–Machine Connection ü Multiple User Operating Systems: UNIX and Linux Ø UNIX was developed at Bell Labs before personal computers were available. Ø Linux was created by Linus Torvalds and continues to be a work-in-progress. ü UNIX allows a timesharing computer to communicate with several other computers or terminals at once. © 2008 Prentice-Hall, Inc. Slide 25

Chapter 4 The User Interface: The Human–Machine Connection Ø Linux is free for anyone to use or improve. Ø UNIX remains the dominant operating system for Internet servers. Ø Some form of UNIX is available for personal computers, workstations, servers, mainframes, and supercomputers. © 2008 Prentice-Hall, Inc. Slide 26

Chapter 4 The User Interface: The Human–Machine Connection Hardware and Software Platforms Windows Vista Windows Server 2003 Mac OS X (10) Windows XP Mac OS 9 Windows ME Linux, Sun Solaris, and other UNIX variations Microsoft Windows CE © 2008 Prentice-Hall, Inc. Slide 27

Chapter 4 The User Interface: The Human–Machine Connection Ø Cross-platform applications, such as Microsoft Office and Adobe Photoshop, are programs that are available in similar versions for multiple platforms. Ø Mac users can buy software emulation programs that: Create a simulated Windows machine in the Mac q Translate all Windows-related instructions Mac equivalents q Ø Future applications may be more tied to networks than to desktop computer platforms Microsoft. NET strategy q Java, a platform-neutral computer language developed by Sun Microsystems for use on multiplatform networks q © 2008 Prentice-Hall, Inc. Slide 28

Chapter 4 The User Interface: The Human–Machine Connection Tomorrow’s User Interfaces ü Future user interfaces will be built around emerging development technologies such as: The end of applications Ø Natural-language interfaces Ø Agents Ø Virtual realities Ø © 2008 Prentice-Hall, Inc. Slide 29

Chapter 4 File Management: Where’s My Stuff? üFiles can be scattered all over the system, which often makes data management difficult. One solution to this problem is to organize data files logically. Ø Both Windows and the Mac support the notion of common system folders with self-explanatory names: Ø q q q My Documents (Documents) My Pictures (Pictures) My Music (Music) © 2008 Prentice-Hall, Inc. Slide 30

Chapter 4 File Management: Where’s My Stuff ü File-Management Utilities Ø View, rename, copy, move, and delete files and folders Ø Hierarchies help with organization Ø Help with locating a file Ø Get size, file type, and last modification date ü Managing Files from Applications Ø Operations: Open, Save As, Save and Close ü Defragmentation © 2008 Prentice-Hall, Inc. Slide 31

Chapter 4 Software Piracy and Intellectual Property Laws ü Software Piracy—illegal duplication of copyrighted software Ø Ø Ø The software industry is a $50 billion a year business sector. Billions of dollars are lost each year to software pirates. One-third of all software is illegally copied. ü Intellectual Property and the Law Ø Intellectual property includes the results of intellectual activities in the arts, science, and industry. Ø Laws ensure that mental labor is justly rewarded and encourage innovation. Ø The information age requires the outdated and inconsistent intellectual property laws to be changed and adapted. © 2008 Prentice-Hall, Inc. Slide 32

Chapter 4 Inventing the Future Tomorrow’s Evolving Applications and Interfaces ü The WIMP (windows, icons, menus, and pointing devices) interface is easier to learn and use than earlier character-based interfaces. ü The SILK interface incorporates many important emerging user interface software technologies: Speech and language Ø Image Ø Knowledge Ø © 2008 Prentice-Hall, Inc. Our goal was bug-free. The new goal is resiliency. —Bob Frankston, in Beyond Calculation Slide 33

Chapter 4 Lesson Summary ü This chapter provides some general answers to the “What is software” question, along with details about each of the three major categories of software: Compilers and other translator programs, which enable programmers to create other software Ø Software applications, which serve as productivity tools to help computer users solve problems Ø System software, which coordinates hardware operations and does behind the scenes work the user seldom sees. Ø © 2008 Prentice-Hall, Inc. Slide 34

Chapter 4 Lesson Summary (continued) ü Popular operating systems include Windows, Mac OS X, UNIX, and Linux. ü The user interface is a critical communication component in operating systems, applications, programming languages, and utilities. ü Tomorrow’s interfaces are likely to rely on threedimensional graphics and animation to create virtual realities. ü Software piracy is a major concern in the computer industry. © 2008 Prentice-Hall, Inc. Slide 35

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