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System software is an essential part of a computer system. This chapter defines system software and discusses two types of system software: operating systems and utility programs. You learn what an operating system is and explore user interfaces, operating systems features, and operating system functions. A variety of popular operating systems are described including DOS, Windows 3.x, Windows 95, Windows 98, Windows 2000, Windows XP, Windows CE, the Mac OS, OS/2, UNIX, Linux, and NetWare. You discover what happens when they start a computer and why a boot disk is important. Finally, a number of utility programs are explained.
Describe the two types of software
Two types of software are application software and system software. Application software consists of programs that perform specific tasks for users, such as a word processing program, e-mail program, or Web browser. System software consists of the programs that control the operations of a computer and its devices. The two types of system software are operating systems and utility programs. An operating system (OS) is a set of programs containing instructions that coordinate all the activities among computer hardware devices. A utility program performs a specific task, usually related to managing a computer, its devices, or its programs.
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Understand the startup process for a personal computer
Booting is the process of starting or restarting a computer. When you turn on the computer, the power supply sends an electrical signal to devices located in the system unit. The processor chip resets itself and looks for the ROM chip that contains the BIOS (basic input/output system), which is firmware that holds the startup instructions. The BIOS executes the power-on self test (POST) to make sure hardware is connected properly and operating correctly. The POST results are compared with data in a CMOS chip on the motherboard. If the POST completes successfully, the BIOS searches for specific operating system files called system files. Once located, the boot drive (the drive from which your personal computer starts), loads the system files from storage (the hard disk – usually drive C) into memory (RAM) and executes them. Next, the kernel of the operating system loads into memory and takes control of the computer. The operating system loads configuration information. In Windows XP, the registry consists of several file that contain the system configuration information. When complete, the Windows XP desktop and icons display, and programs in the StartUp folder are executed.
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Describe the term user interface
A user interface controls how you enter data and instructions and how information displays on the screen. Two types of user interfaces are command-line and graphical. With a command-line interface, you type keywords or press special keys to enter data or instructions. A graphical user interface (GUI) allows you to use menus and visual images such as icons, buttons, and other graphical objects to issue commands. A menu is a set of commands from which you can choose. An icon is a small image that represents a program, an instruction, a file, or some other object.
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Explain features common to most operating systems
Most operating systems perform similar functions that include managing programs, managing memory, scheduling jobs, configuring devices, accessing the Web, monitoring performance, providing housekeeping services, and administering security. Managing programs directly affects your productivity. A single user/single tasking operating system allows only one user to run one program at a time. A multitasking operating system allows a single user to work on two or more applications that reside in memory at the same time. A multi-user operating system enables two or more users to run a program simultaneously.
A multiprocessing operating system can support two or more CPUs running programs at the same time. Managing memory involves assigning items to an area of memory while they are being processed. The purpose of memory management is to optimize use of random access memory (RAM). With virtual memory (VM), the operating system optimizes memory by allocating a portion of a storage medium, usually the hard disk, to function as additional RAM. Scheduling jobs (operations the processor manages) involves determining the order in which jobs are processed.
Spooling increases efficiency by placing print jobs in a buffer (an area of memory or storage where data resides while waiting to be transferred) until the printer is ready, freeing the processor for other tasks. Configuring devices establishes communication with each device in the computer. A device driver is a small program that tells the operating system how to communicate with a device. Accessing the Web may entail including a Web browser and e-mail program in the operating system. Monitoring performance helps to identify and solve system problems.
A performance monitor is a program that assesses and reports information about various system resources and devices. Providing housekeeping services entails performing storage and file management functions. A file manager performs such functions as formatting and copying disks; listing the files on a storage medium; checking the amount of used and unused space on a storage medium; organizing, copying, deleting, moving, and sorting files; and creating shortcuts (icons on the desktop that run a program when clicked).
Administering security involves establishing user accounts on a network. Each account typically requires a user name and a password to log on, or access, the network.
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Know the difference between stand-alone operating systems and network operating systems
A stand-alone operating system is a complete operating system that works on a desktop or notebook computer. A network operating system (also called network OS or NOS) is an operating system that supports a network. A network is a collection of computers and devices connected together via communications media and devices such as cables, telephone lines, and modems. In some networks, the server is the computer that controls access to the hardware and software on a network and provides a centralized storage area. The other computers on the network, called clients, rely on the server(s) for resources.
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Identify various stand-alone operating systems
Stand-alone operating systems include DOS, Windows 3.x, Windows 95, Windows NT Workstation, Windows 98, Windows 2000 Professional, Windows Millennium Edition, Windows XP Home Edition, Windows XP Professional Edition, Mac OS, OS/2 Warp Client, UNIX, and Linux. UNIX and Linux also function as network operating systems.
DOS (Disk Operating System) refers to several single user, command-line and menu-driven operating systems developed in the early 1980s for personal computers. Windows 3.x refers to early operating environments that, although not operating systems, provided a graphical user interface to work in combination with DOS and simplify its use. Windows 95 is a true multitasking operating system – not an operating environment – with an improved graphical interface. Windows NT Workstation is a client operating system that can connect to a Windows NT Server. Developed as an upgrade to Windows 95, the Windows 98 operating system is easier to use and more integrated with the Internet. Windows 98 includes Microsoft Internet Explorer, a popular Web browser, Windows Explorer, a file manager, and an Active Desktop™ that works similarly to Web links. Windows 2000 Professional is a complete, reliable multitasking client operating system for business desktop and business notebook computers. Windows Millennium Edition is an operating system that has features specifically for the home user. Windows XP is Microsoft’s fastest, most reliable Windows operating system, providing quicker startup, better performance, and a new, simplified visual look. Windows XP Home Edition is an upgrade to Windows Millennium Edition, while Windows XP Professional Edition is an upgrade to Windows 2000 Professional.
The Mac OS, the latest version of the Macintosh operating system (the first commercially successful graphical user interface), is a multitasking operating system available only on Apple computers. OS/2 Warp Client is IBM’s GUI multitasking client operating system that supports networking, Java, the Internet, and speech recognition.
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Identify various network operating systems
Network operating systems include NetWare, Windows NT Server, Windows 2000 Server, Windows .NET Server, OS/2 Warp Server for E-business, UNIX, Linux, and Solaris™. Novell’s NetWare is a widely used network operating system designed for client/server networks. Windows NT Server is the operating system used by servers in the Windows NT client/server network environment. The Windows 2000 Server family consists of three products: Windows 2000 Server (for the typical business network), Windows 2000 Advanced Server (for e-commerce applications), and Windows 2000 Database server (for demanding, large-scale applications). Windows .NET Server is an upgrade to Windows 2000 Server. The Windows .NET Server family includes four products: Windows .NET Standard Server (for the typical small- to medium-sized business network), Windows .NET Enterprise Server (for medium- to large-sized businesses, including those with e-commerce applications), Windows .NET Datacenter (for business with huge volumes of transactions and large-scale databases), and Windows .NET Web Server (for Web server and Web hosting businesses).
OS/2 Warp Server for E-business is IBM’s network operating system designed for all sizes of business.
UNIX is a multitasking, command-line operating system implemented on many different types of computers. Because it is both a stand-alone operating system and a network operating system, some call UNIX a multipurpose operating system. Linux is a popular, free, multitasking UNIX-type operating system. Solaris™, a version of UNIX developed by Sun Microsystems, is a network operating system designed for e-commerce applications.
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Recognize devices that use embedded operating systems
The operating system on most handheld computers and small devices, called an embedded operating system, resides on a ROM chip. Popular embedded operating systems include Windows CE, Pocket PC OS, and Palm OS®. Windows CE is a scaled-down Windows operating system designed for use on wireless communications devices and smaller computers such as handheld computers, in-vehicle devices, and Web-enabled devices. Pocket PC OS is a scaled-down operating system developed by Microsoft that works on a specific type of handheld computer, called a Pocket PC. The Palm OS® is the operating system used on Palm handheld computers from Palm, Inc., and Visor handheld computers from Handspring™.
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Discuss the purpose of the following utilities: file viewer, file compression, diagnostic, uninstaller, disk scanner, disk defragmenter, backup, and screen saver
Most operating systems include several utility programs that perform specific tasks related to managing a computer, its devices, or its programs. A file viewer is a utility that allows you to display and copy the contents of a file. A file compression utility shrinks the size of a file. A diagnostic utility compiles technical information about a computer’s hardware and certain system software programs and then prepares a report outlining any identified problems. An uninstaller is a utility that removes an application, as well as any associated entries in the system files. A disk scanner is a utility that (1) detects and corrects both physical and logical problems on a hard disk, and (2) searches for and removes unnecessary files.
A disk defragmenter is a utility that reorganizes files and unused space on a computer’s hard disk so data can be accessed more quickly and programs can run faster. A backup utility copies, or backs up, selected files or an entire hard drive onto another disk or tape. A screen saver is a utility that causes the monitor’s screen to display a moving image on a blank screen if no keyboard activity occurs for a specified period.
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|Expand Your Knowledge||
Here you will find additional information that will expand and enhance your knowledge beyond that contained in your textbook. Compare this information to what may be provided in a traditional classroom by your instructor or peers.
Software is a key component of any information system. Of the total number of corporate dollars spent on computing, the software share is increasing while the hardware share is decreasing. Typically, different sizes of computers use different operating systems, and even the same types of computers may not use the same operating system. The operating system that a computer uses sometimes is called the software platform, or platform. Application software packages often require a specific software platform. A cross-platform application, however, is one that runs on multiple operating systems.
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Starting a Computer
When you turn on a computer after it has been powered off, you are performing a cold boot. When you restart a computer that already has been powered on, you are performing a warm boot. Your typically can perform a warm boot by pressing a combination of keys on the keyboard (in Windows, ctrl+alt+del), selecting options from a menu, or pressing a Reset button on the computer.
If you watch the screen closely as the POST is conducted, the value for the total amount of memory can be seen to change as it is measured in the memory test. If the POST results do not match the data on the CMOS chip, an appropriate message should appear. The boot program typically is the first side, first track, and first sector of the hard disk. When you install an operating system, one of the installation steps involves making an emergency disk from which you can start your computer if the hard disk is damaged.
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You can interact with an operating system directly (as you do when copying files, moving files, formatting disks, and so on) or indirectly (as you do when working with an application program). An operating system is intended to be transparent; that is, it does not have to be understood, considered, or even known. The operating system with which an application program will work is specified on the application software package. The application programs you want to use should be considered before deciding on an operating system, and the operating system must be considered when choosing application software.
A graphical user interface is designed to be easier to use (more user-friendly) than a command-line interface. As an example of this user-friendly nature, consider how a relatively simple task, such as deleting a file, is performed with a command-line interface and with a GUI. With a command-line interface, you might type del followed by the file name in quotation marks. Therefore, you must remember the command, type it correctly, and use the proper syntax. On the other hand, with a GUI you need only select (click) the file name in the file manager window and then click the Delete command on a menu or the Delete button on a toolbar. Although most people find a GUI the easiest interface to use, some long-time computer virtuosos still feel a command-line user interface is more efficient.
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Features of Operating Systems
Early operating systems were single user/single tasking, but today most operating system are multitasking. Multitasking can be cooperative, in which programs switch when they reach a logical break point, or preemptive, in which programs switch based on priority and an allocated amount of time. Early versions of Windows used cooperative multitasking; Windows 95 and subsequent versions use preemptive multitasking. Upon termination, most programs relinquish their space in memory, which then is reallocated by the operating system. Some programs, however, stay in memory after they terminate. As a class, these programs are called TSR (Terminate and Stay Resident) programs.
Virtual memory is employed with multitasking operating systems to maximize the number of programs that can use memory at one time. Paging, or the technique of swapping items between memory and storage, was developed before processors could address directly more than 1 MB of memory. All printers have buffers, and printer manufacturers are eager to sell DRAM. The term spooling comes from the observation that placing print jobs temporarily in a buffer is somewhat like winding thread onto a spool so that it can be used at a later time. Today, adding and configuring devices is easier because most devices support Plug and Play, which means the computer can recognize a new device and automatically load the necessary drivers. A feature of Windows 95, Plug and Play initially was greeted with mixed reviews. In fact, some wags claimed the new technology was more accurately called, “Plug and Pray.”
Processor utilization – the amount of time that the processor is working and not idle – is one way of monitoring system performance. In addition to the programs that come with most operating systems, several utility programs are available to monitor system performance. Formatting a disk is the process of preparing it for reading and writing. Today, most floppy and hard disks are preformatted by the manufacturer. If you format a disk that already contains data, the formatting process erases the file location information, but it does not erase the actual files on the disk. Therefore, if you accidentally format a disk, often you can unformat it with a utility program. System security usually is most important for large systems or networks. For single-user PCs, adequate system security can be a key in the user’s pocket.
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Stand-Alone and Network Operating System
Many early operating systems were device dependent and proprietary. Device-dependent operating systems run only on a specific type of computer. Proprietary software is privately owned and limited to a specific vendor or computer mode. Today, the trend is towards device-independent operating systems that run on many manufacturers’ computers. Software that is not proprietary (i.e., that can work with a variety of computer models) sometimes is called portable or generic. Most of the operating systems discussed in this section are portable. When an operating system is proprietary, usually it is to boost hardware sales.
Operating systems for Apple computers and most mainframes initially were proprietary. Steve Wozniak, cofounder of Apple Computers, believes the decision to make its innovative Macintosh operating system proprietary was one of the company’s greatest mistakes. “We had the most beautiful operating system,” Wozniak writes, “but to get it you had to buy our hardware at twice the price.” Wozniak now feels the operating system should have been licensed.
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Stand-Alone Operating Systems
Bill Gates, founder of Microsoft and one of the wealthiest men in the world, began his fortune with the MS-DOS operating system. Although developed for IBM, Microsoft retained the rights to the operating system and licensed the source code to several hardware manufacturers, which resulted in multiple variations. An application written for one type of DOS, however, will work with any other variation. A number follows each version of PC-DOS or MS-DOS. The integer portion of the number indicates a major release, while the decimal portion indicates updates. Thus, MS-DOS 6.2 means major version six, which has been updated twice. To a great extent, the popularity of DOS was a result of the large number of applications written to work with the operating system.
Windows 1.0, released in 1985, was Microsoft’s first attempt with a graphical user interface. It was not until five years later, however, with the release of Windows 3.0, that computer users began to take Windows seriously. Windows required 2 MB of memory (with 4 MB recommended) and an 80386 or newer processor, so it could not be used with many older PCs. Nevertheless, because Windows 3.0 was easier to use than DOS, eventually most software was written, and many popular DOS programs were rewritten, to work with Windows.
Despite the advantages of Windows 95 and a heavily-funded promotional campaign, a poll of DOS and Windows 3.x users showed not everyone immediately embraced the new operating system. When asked how likely they were to adopt Windows 95 within the next six months, respondents replied:
- extremely likely 10%
- possible 35%
- not likely 53%
- don’t know 2%
Why are people often reluctant to adopt a new operating system?
The inclusion of Internet Explorer in the Windows 98 operating system led to an antitrust suit against Microsoft. Prosecutors insisted that the incorporation of a browser was an attempt by Microsoft to eliminate competition from rival Web browsers (such as Netscape Navigator). Microsoft maintained that the addition simply was an enhancement to the operating system. Although Microsoft advertised Windows 98 less heavily than Windows 95, many vendors took up the slack. One retailer offered Windows 98 with the opportunity to buy a new computer for $98. The promotion evidently worked. A buyer waited in line 11 hours for a chance to buy the new operating system and discount computer. When asked if he would have come out simply for Windows 98 (his current computer ran Windows 3.1), he replied, “Not a chance.”
Windows 2000 was released in February, 2000 and was touted as a boon for all businesses, from small companies with no more than two desktop computers to large corporations with vast networks. Windows Millennium is a result of Microsoft’s recognition that the needs of business and home users are different.
For years, the Macintosh operating system had features that made it far easier to use than other operating systems. For example, people could give files sensible names (like “Letter to Grandma”) instead of the cryptic, eight-character strings (like “letgrand.txt”) demanded by DOS and Windows 3.x. While Windows 95 incorporated many of these features, Macintosh devotees still feel their operating system is easier to use. Until recently, the Macintosh operating system was proprietary. In 1994 the operating system was licensed, but experts feel Apple’s promotion has been lukewarm. New standards let IBM computers run Apple software. More than 4,000 applications are designed to run under the Mac OS. Microsoft has developed the more popular Mac OS applications.
IBM supplies OS/2 (Operating System/2) Warp with its high-end personal computers. OS/2 originally was developed jointly by IBM and Microsoft to replace MS-DOS. As an interim measure, Microsoft developed Windows, an operating environment to work with DOS. The eventual popularity of Windows, coupled with the initial poor sales of OS/2, resulted in Microsoft and IBM going their separate ways, with Microsoft concentrating on Windows and IBM continuing to develop OS/2. Features offered in OS/2 Warp include:
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Network Operating Systems
Many consider UNIX to be the most portable operating system. Although it has some shortcomings, UNIX often is used in “turnkey” systems designed for retail stores, doctors, dentists, veterinarians, and other small- to medium-businesses. Do you know what operating system is mentioned in the film Jurassic Park? UNIX.
Despite the current dominance of Windows, some believe Linux is the operating system of the future. Because Linux is freeware, users can modify and improve the program code. In addition, Linux is capable of running efficiently with less powerful processors, even the 80386. The story of Linux’s originator, Linus Torvalds, is told in the Technology Trailblazer on page 8.25.
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Embedded Operating Systems
The latest Palm handheld computer, Palm IIIC, offers a color screen. When paired with a portable, expandable, attachable, nearly full-sized keyboard and file compression software, some reviewers say the Palm IIIC almost can replace a laptop. The Visor handheld computer runs the same operating system as the Palm but offers several additional features – videogames, cell telephone, modem, MP3 player, and two-way pager – at about half the cost.
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Utilities generally reside in storage until summoned by the user or operating system kernel. Microsoft was the target of several lawsuits for allegedly incorporating utility programs developed by others into their DOS operating system. Some versions of DOS were modified because of this litigation. In light of the ever-increasing number of utility programs included with operating systems, will a market remain for separate utility programs?
In addition to the utilities mentioned in this chapter, other Windows 98 utilities include:
Some stand-alone utilities include:
Some utility programs are used primarily by select groups. For example, text editors -- utility programs that make it easy to work with lists and records -- are popular with programmers and people who work with databases. PC Tools and Norton Utilities are popular utility software packages for personal computers.Back to Top
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