Transcript Chapter 4
Chapter 4 System Software Software Programs that tell a computer what to do and how to do it. Programs Sets of instructions telling computers to perform actions in a certain order. The Two Main Categories 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 User Interfaces (GUIs) Accept user commands in the form of mouse clicks on icons or menu items. Graphical User Interfaces (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 • • • UNIX was the first language of the Internet. Uses a complex commandline interface Offers simultaneous access by many users to a single powerful computer Cross-platform operating system 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 Device Operating Systems Windows CE Palm OS 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 Language Translators 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 SOFTWARE Suites 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 SYSTEMS Operating 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).