Chapter 4 System Software. Software Programs that tell a computer what to do and how to do it. Sets of instructions telling computers to perform actions.

Chapter 4System Software

Software

Programs that tell a computer what to do and how to do it.

Sets of instructions telling computers to perform actions in a certain order.

Programs

The Two MainCategories of Software

Application Software

System Software

System Software

System software includes programs that manage the basic operations of a computer such as starting up and saving and printing files.

Application Software

Application software includes programs that perform a single task such as spreadsheet analysis.

Operating System

• manages main memory, or RAM• controls and configures peripheral devices• formats and copies disks• manages essential file operations• monitors system performance• provides a user interface.

How A Computer Boots Up

RAM

Windows loads portions of code into all three areas of RAM on startup.

Platform

Platform is determined by the type of computer and processor.

Software User Interfaces

All software, including operating systems, must have a user interface to allow communication between the software and the user. The interface controls the manner in which data and commands are entered and the way information and processing options are presented on the screen.

Two Types of User Interfaces

Command-line interfaces

Graphical user interfaces (GUIs)

Command-line interfaces

Designed to accept commands from the user in the form of lines of text code. The DOS operating system has a command-line interface.

Graphical UserInterfaces (GUIs)

Accept user commands in the form of mouse clicks on icons or menu items.

Graphical UserInterfaces (GUIs)

• Common command icons

• On-screen desktop

• Display windows

• Key feature option menus

• Dialog boxes

• Online Help

PC Operating Systems

Microsoft Windows

Novell NetWare

Macintosh, UNIX, and OS/2

Microsoft Windows

• Developed in 1985• Increasingly has dominated PC

market • Most recent version: Windows XP• Has required more powerful

microprocessors and more disk space with each release (software driving hardware)

• Under development: Windows Longhorn (working name)

Microsoft Windows

Clicking the Start button in Windows XP displays a menu of options, including:

• My Documents• My Recent Documents• My Computer• My Network Places• Help and Support• Search• Run• Log Off• Shut Down• And others. . .

Microsoft Windows

Windows and other GUIs allow users to work with multiple applications at the same time.

Novell NetWare

Novell NetWare is a popular and widely used operating system for microcomputer-based local area networks.

UNIX

• Uses a complex command- line interface• Offers simultaneous access by many users to a single powerful computer• Cross-platform operating system

UNIX was the first language of the Internet.

Macintosh

The Mac OS was the first commercial GUI, serving as a model for the Windows GUI that followed. Long a favorite of graphic artists and designers, the Mac OS only runs on Apple Macintosh computers.

Macintosh OSX

Its newest version, Mac OS X, includes a new interface called Aqua and is based on the UNIX operating system.

OS/2 Operating Systems

IBM’s OS/2 GUI operating system was developed to compete with Microsoft Windows and the Apple Mac OS. The latest version, OS/2Warp, can run programs written for both DOS and Windows systems. A network server version also has been developed.

Server Operating Systems

Windows NT Server

Windows 2000 Server

Windows Server 2003

UNIX

Linux Netware 6

Wireless DeviceOperating Systems

Palm OS Windows CE Pocket PC

Microsoft’s .NET Initiative

– The .NET Initiative incorporates applications and a suite of tools

and services that operate over

the Internet, using XML.– Users will rent applications

over the Internet and will be

able to integrate fax, e-mail,

and phone services.

– The Internet will house all of a user’s data.

Utilities

A utility program performs a single maintenance or repair task.

Utilities

• Virus checkers• Diagnostic utilities• Uninstallers• Disk scanners• Disk defragmenters• File compression

utilities• Backup utilities• Disk toolkits• Spam blockers

Language Translators

Convert high-level program languages into machine language so the computer can run the program.

Types of LanguageTranslators

Compilers

Interpreters

Compilers

Compilers translate an entire program at once

Interpreters

Interpreters act on just one line of instruction at a time.

On the Horizon

USER-FRIENDLY SYSTEM SOFTWARE

In the future, system software users may be able to click on wizard icons to automatically perform tasks such as formatting disks or copying files.

IMPROVED UTILITIES SOFTWARESuites containing all needed utilities, including antivirus programs, a firewall that automatically blocks Internet hackers, and programs that can identify hacker locations.

NEW USER INTERFACE DESIGN FOR OPERATING SYSTEMSOperating systems for the PC are evolving in an “all-in-one” direction.

LINUX: AN OPEN-SOURCE CHALLENGE TO WINDOWS?Fans of Linux praise its stability, flexibility, and generally low cost (vendors usually package it with various tools; hence there is a charge).