3 3 3 CHAPTER System Software

3 Objectives By the end of this lecture, you should know how to: –Describe the differences between system software and application software. –Discuss the three basic functions of any operating system. –Describe the three categories of operating systems. –Discuss the purpose of utilities and utility suites. –Identify the five most essential utilities. –Define device drivers. –Discuss language translators.

3 Systems Software Background software that helps you interact with the computer Designed to handle –Technical details –Where programs stored –How commands executed –Where files saved –How output handled

3 Four Kinds of Programs Operating system Utilities Device drivers Language translators

3 Four Kinds of Programs Utilities –perform specific tasks related to managing computer resources. Device drivers –specialized programs designed to allow particular input or output devices to communicate with the rest of the computer system. Language translators –convert the programming instructions written by programmers into a language that computers understand and process.

3 Operating Systems Every operating system performs three basic functions: 1.Resource management coordinate keyboard, mouse, printer, monitor, storage devices, and memory. 2.Provide a user interface users interact with application programs and computer hardware through a windows-like graphical user interface (GUI) that use graphic objects called icons to represent commonly used features. 3.Run applications the OS loads and runs application programs, such as word processors and spreadsheets, and support multitasking, which is the ability to run more than one application at a time.

3 Operating Systems Some widely used operating systems are: Windows Mac OS Unix

3 Windows Windows is the most popular microcomputer operating system. Windows gets its name from its use of rectangular boxes called windows. Over 80 percent of the market now uses Windows. It is designed to run with Intel and Intel compatible microprocessors such as Pentium IV.

3 Windows Versions of Windows include –Windows 95 –Windows 98 –Windows 2000 –Windows ME –Windows XP

3 Windows Multitasking - different programs running simultaneously with this operating system. The user interface of Windows is called the desktop. The desktop has two views: –Classic –Web style – look and feel of Internet Explorer browser. Windows and many other operating systems store information in a system of files and folders. Files are used to store data and programs and are stored on a secondary storage device such as the hard disk. Related files are stored within a folder, and for organization purposes, a folder can contain other folders.

3 Windows The common way for users to interact with the Windows operating system is by selecting icons. The Start Menu of Windows displays a list of commands used to: –Gain access to information. –Change hardware settings. –Find information. –Get online help. –Run programs. –Log off a network. –Shut down the computer.

3 Mac OS Operating system designed to run only on Macintosh computers. It is a very powerful and easy to use operating system and comes in a variety of versions. Its market share is much less than Windows. Mac OS includes several unique features: –Sherlock - an innovative search feature for locating information on the Web or hard drive. –Aqua – an intuitive user interface. –Dock – provides a flexible tool for organizing files.

3 Unix The Unix operating system was originally designed to run on minicomputers in network environments. A powerful operating system for microcomputers and servers on the Web. One important version of Unix is called Linux. Linux is not a proprietary operating system (it is not owned and licensed by a company). It was developed in 1991 by Linus Torvalds, a graduate student at the University of Helsinki. Torvalds provided the operating system free to others. Linux Unix

3 Categories of OS 1.Embedded – hand-held 2. Network OS – linked computers 3. Stand-alone OS – desktop

3 Categories of OS Embedded operating systems: Used for handheld computers and smaller devices like PDAs. Completely stored within the device in its ROM memory. Popular embedded operating systems include Windows CE and Palm OS.

3 Categories of OS Network operating systems (NOS): Used to control and coordinate computers that are linked together. Typically located on one of the connected computers hard disks. Called the network server, this computer coordinates all communication between linked computers. Popular network operating systems include NetWare, Windows NT Server, Windows XP Server, and UNIX.

3 Categories of OS Stand-alone operating systems (desktop operating systems): Control a single desktop or notebook computers. Located on the computer’s hard disk. Often desktop computers and notebooks are part of a network. –The desktop operating system works with the network’s NOS to share and coordinate resources. –Referred to as the client operating system Popular desktop operating systems include Windows, Mac OS, and some versions of UNIX.

3 Utilities Utilities are specialized programs designed to assist users with tasks that will help run their computers without problems. Most operating system programs provide some utility programs. More powerful utility programs can be purchased.

3 Essential Utilities Troubleshooting Antivirus Uninstall Backup File compression

3 Utilities Troubleshooting programs that recognize and correct problems. Antivirus programs that guard your computer against viruses. Uninstall programs that allow you to remove unneeded programs from your hard disk. Backup programs programs that make copies of your files. File compression programs programs that reduce the size of files.

3 Windows Utilities Backup –utility program that makes a copy of selected or all files that have been saved onto a disk. It helps to protect you from the effects of a disk failure. Disk cleanup –troubleshooting utility that identifies and eliminates nonessential files. This frees up valuable disk space and improves system performance. Disk defragmenter –utility program that locates and eliminates unnecessary fragments and rearranges files and unused disk space to optimize operations. These utilities can be accessed from the Systems Tools menu.

3 Utility Suites Several utility programs sold in a package is called a utility suite. The cost of the utility suite package is less than buying the programs separately. Two best-known utility suites are: –McAfee Office. –Norton System Works. –DataFellows

3 Norton System Works Norton System Works includes a suite of five separate program groups. Each group can be purchased separately or as part of the suite. The five groups of Norton System Works are: 1.Norton Utilities – a collection of 17 separate trouble-shooting utilities. –finding and fixing problems –improving system performance –preventing problems from occurring –troubleshooting other problems

3 Norton System Works 2.Norton AntiVirus – a collection of antivirus programs. –protection from over 21,000 different viruses –quarantine or delete existing viruses –automatically update its virus list to check for newest viruses

3 Norton System Works 3.Norton CleanSweep – a collection of programs to safely remove programs and files. –Archive, move, backup files –Clean up your hard drive –Protects existing files from damage 4.Norton CrashGuard – a collection of trouble-shooting utilities. –automatically protects against programs that crash or freeze the display screen –provides options to recover your current work before an event causes a crash or freeze

3 Norton System Works 5.Norton Web Services – utilities to keep you alert. –monitors system for out-of-date software –notifies you of available software updates that can be installed from the Internet

3 Device drivers Specialized programs Loaded into memory each time Add new device: install device driver –Whenever a new device is added to the computer system, a new device driver must be installed before the device can be used.

3 Device drivers Drivers work with the operating system to allow communications between the device and the rest of the computer system. Many times, device drivers are available directly from the manufacturer’s Web site. Windows provides an Add/Remove Hardware Wizard that offers step-by-step guidance for the installation and removal of device drivers.

3 Language translators Language translators convert human-oriented programming languages to machine language. Computers only understand a language consisting of 0’s and 1’s called machine language. To ease the burden of programming entirely in 0’s and 1’s, special programming languages were develop that more closely approximate human language. Language translators convert these programming statements into the zeros and ones that the computer is able to process.