Tomorrow’s Technology and You 9/e Chapter 4 Software Basics: The Ghost in the Machine Slide 1...

Tomorrow’s Technology and You 9/e

Chapter 4Software Basics: The Ghost

in the Machine

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

Tomorrow’s Technology and You 9/e Chapter 4

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



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.

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




Device Drivers 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


Type of Utility Software• Disk defragmentation

– Optimizes hard disk performance by arranging files into contiguous sectors

• Backup programs– Used to compress and back up important files

• Encryption– Secure files, folders, and disks in the event of theft of loss of the

computer

• System monitoring– Monitors system resources such as processor and memory

usage and optimizes them to improve performance

• Disk clean up– Detects and deletes unneeded files, such as temporary files

created by some applications.ITGS, Stuart Gray pg. 47

Types of Utility Software (cont’d)

• Accessibility options– Sets options for disabled users, such as increased font size

or screen contrast.• Anti-virus software

– Used to detect and remove malicious software such as viruses, Trojan horses and spyware.

• System updates– Updates the operating system with the latest security and

performance patches released by the software’s creator.

• Compression software– Used to compress files to save disk space or network

bandwidth.

ITGS;, Stuart Gray pg. 47



Slide 17

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.

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.

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

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 (command line interface) Letters Numbers Symbols

Different types of interfaces Command-line interface (commands are typed) Menu-driven interface (commands are chosen from on-screen

lists) 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. (Open source software) 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 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.




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

Cloud Computing

• Advantages– Software and data are available from any location that has Internet

access, regardless of the computer being used.– There is no need to manage, maintain, and upgrade a network of

computers with lots of application software installed. Upgrades to the cloud software are automatically available on all computers immediately.

– Reliability and Integrity: there is less need to maintain back-up and test procedures for data stored on the cloud.

– Some cloud computing applications let multiple users work simultaneously on the same document (collaborative working.)

Slide 21

Cloud Computing

• Disadvantages– Reliability: A fast and reliable Internet connection is required. Unreliable

connections may result in inability to work for long periods of time. If lots of users are using the cloud computing system, a lot of bandwidth is needed.

– Security: You are reliant on the cloud computing provider having adequate security measures to prevent your data falling into the hands of unauthorized users both during transit and when stored on the remote server.

– Reliability and integrity: You are relying on the cloud computing provider to have adequate backup procedures to prevent loss of data if their systems fail

– Globalization and Cultural Diversity: There are concerns about the legal status of data stored on serves in different parts of the world. Varying international laws may mean that data is subject to government inspection or may be considered illegal, even though it would not be in the user’s home country.

Slide 22


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.


Tomorrow’s Technology and You 9/e Chapter 4 Software Basics: The Ghost in the Machine Slide 1...

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