Fundamentos de Software

Slide 1Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Power Point Lectures to accompany Tomorrow’s Technology and You, 9e

Slide 2

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written permission of the publisher. Printed in the United States of America.

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

Tomorrow’s Technology and You 9/e

Chapter 4Software Basics: The Ghost

in the Machine


Tomorrow’s Technology and You 9/e Chapter 4Objectives

Describe three fundamental categories of software and their relationship

Explain the relationship of algorithms to software

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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Tomorrow’s Technology and You 9/e Chapter 4Objectives

Describe how file systems are organized

Outline the evolution of user interfaces from early machine-language programming to futuristic virtual-reality interfaces

Explain why unauthorized copying of software is against the law


Tomorrow’s Technology and You 9/e Chapter 4

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.



Linus Torvalds and the Software Nobody Owns

Computer programs 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

Application vs. Operating Systems


Tomorrow's Technology and You 9/e Chapter 4

Processing with Programs

Food for thoughtThe hardware in a computer system is

equipped to produce whatever output a user requests.




A fast, stupid machine Programmers begin with an

algorithm: a set of step-by-step instructions written in a natural language, for example, English.

The steps are often ambiguous, error-prone generalities.

The steps are translated into the vocabulary of a programming language.

Debugging is done to correct errors.




The language of computers Machine language: numeric

codes that represent basic computer operations

High-level language: falls between machine language and natural human language (C++, Java, VB.NET, etc.)Compilers translate high-

level language into machine language.

Natural languages: resembles languages used by humansTranslation software

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The programmer, like the poet, works only slightly removed from

pure thought-stuff. 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



Software Applications: Tools for Users

Consumer applicationsMany software companies have replaced

or supplemented the printed documentation with:TutorialsReference materialsHelp files Online help




Consumer applications (cont.) Updating: minor bug fixes and enhancements 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.

Service Packs contain minor revisions and are usually free.




Consumer applications (cont.) Compatibility

It 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.

DisclaimersSoftware manufacturers limit their liability for software

problems by selling software “as is.”EULA (End User License Agreement )




Consumer applications (cont.) Licensing: Commercial software is copyrighted so it can’t be

legally duplicated for distribution to others.Software license Volume licenses

Distribution of software via:Direct salesRetail stores Mail-order catalogsWeb sites

Not all software is copyrightedPublic domain software Shareware




Web applications Web applications fall into several categories:

Some 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 Other Web applications support a more traditional form of information

broadcasting




Vertical-market & custom software Tends to cost far more than

mass-market applications Job-specific software:

Medical billings Library cataloging Legal reference software Restaurant management Single-client software needs



System Software: The Hardware-Software Connection

What the operating system does System software

A class of software that includes the operating system and utility programs, handles these details and hundreds of other tasks behind the scenes.

Slide 18

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




What the operating system does (cont.) Operating system functions:

Supports multitaskingManages virtual memoryMaintains file systemResponsible for

authentication and authorization




Utility programs and device drivers Utility programs

Serve as tools for doing system maintenance and repairs that aren’t 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




Utility programs and device drivers (cont.) Symantec Norton Utilities is a popular utility package that includes

software tools for recovering damaged files, repairing damaged disks, and improving disk performance.




Utility programs and device drivers (cont.) Device drivers

Small programs that enable I/O devices—keyboard, mouse, printer, and others—to communicate with the computer

Included with the operating system, bundled with peripherals, or given away as separate products




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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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Where the operating system lives (cont.)

Most of the time the operating system 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.



The User Interface: The Human–Machine Connection

User interface The interface defines the look and feel of the computing

experience from a human point of view.

Desktop operating systems MS-DOS is an operating system in which the user interacts

using characters rather than graphics: Letters Numbers Symbols


Tomorrow's Technology and You 9/e Chapter 4


Desktop operating systems (cont.) Features include:

Command-line interface (commands are typed)

Menu-driven interface (commands are chosen from on-screen lists)




Desktop operating systems (cont.) GUI (Graphical User Interfaces), pronounced “gooey”

Mac OS was developed by Macintosh in 1984 using GUI. Microsoft Windows is now the most popular operating system.




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. UNIX has dominated the multi-user server market for decades. Many choose to use dual-boot PCs to switch between Windows

and Linux, simply, by rebooting.




UNIX and Linux (cont.)

UNIX allows a timesharing computer to communicate with several other computers or terminals at once.

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.




Hardware and software platforms

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Windows Vista–5 versions

Windows Server 2008

Windows XP

Windows CE

Windows Mobile

Mac OS X (10)

Mac OS 9

Linux, Sun Solaris, and UNIX variations

BlackBerry OS

Palm OS




Cross-platform applications, such as Microsoft Office and Adobe Photoshop, are programs available in similar versions for multiple platforms.

Mac users can buy software emulation programs that: Create a simulated Windows machine in the Mac Translate all Windows-related instructions to Mac equivalents

Future applications may be tied to networks rather than to desktop platforms Microsoft.NET strategy Java, a platform-neutral computer language developed by Sun

Microsystems for use on multiplatform networks Virtual machines


Hardware and software platforms (cont.)



Future user interfaces will be built around emerging development technologies such as:

The end of applications Natural-language interfaces Agents Virtual realities


Tomorrow’s user interfaces


File Management: Where’s My Stuff?

Organizing files and folders 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)



File Management: Where’s 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




Locating files Modern operating systems include search tools that can

help you find files New operating systems have built in file management

tools to help users keep track of files Virtual folders can “contain” files located all over your

computer




Defragmentation: the cure for fragmented files

As you work with a file, its contents become scattered into different tracks and sectors of your hard drive.



Software Piracy and Intellectual Property Laws

The piracy problem The software industry is a $50 billion a year business sector. Billions of dollars and tens of thousands of jobs are lost each

year to software pirates. One-third of all software is illegally copied.

Intellectual property and the law Intellectual property includes the results of intellectual activities

in the arts, science, and industry. Laws ensure that mental labor is justly rewarded and encourage

innovation. (Copyright, Trademark, Patent, etc.) The information age requires the outdated and inconsistent

intellectual property laws to be changed and adapted.



Inventing the Future Tomorrow’s Evolving Applications and Interfaces

The WIMP (windows, icons, menus, and pointing devices) interface is easier to learn and use than earlier character-based interfaces.

The SILK interface incorporates many important emerging user interface software technologies: Speech and language Image and virtual reality Knowledge

Slide 38

Our goal was bug-free. The new goal is

resiliency. —Bob Frankston, in Beyond Calculation



Lesson Summary

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 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 user seldom sees



Lesson Summary (cont.)

Popular operating systems include Windows, Mac OS X, UNIX, and Linux.

The user interface is a critical communication component in operating systems, applications, programming languages, and utilities.

Tomorrow’s interfaces are likely to rely on three-dimensional graphics and animation to create virtual realities.

Software piracy is a major concern in the computer industry.
