Objectives. After completing this chapter, you will be able to complete tasks related to

Transcription

1 0971fmi.book Page 2 Thursday, January 30, :45 PM Objectives After completing this chapter, you will be able to complete tasks related to Operating system basics Microsoft Windows UNIX and Linux on the desktop Network operating systems

2 Chapter 1 Operating System Fundamentals The first personal computers (PCs) were designed as standalone desktop systems. The operating system (OS) software allowed one user at a time to access files and system resources. The user had physical access to the PC. As PC-based computer networks gained popularity in the workplace, software companies developed specialized network operating systems (NOSs). Developers designed NOSs to provide file security, user privileges, and resource sharing among multiple users. The explosive growth of the Internet compelled developers to build the NOSs of today around Internet-related technologies and services such as the World Wide Web. Within a decade, networking has become centrally important to desktop computing. The distinction between modern desktop operating systems, now loaded with networking features and services, and their NOS counterparts has blurred. Now, most popular operating systems such as Microsoft Windows 2000 and Linux are found on high-powered network servers and on end users desktops. This course examines the components of the most popular NOSs in use today, including Windows 2000 and Linux. This chapter reviews desktop operating systems, including their components, their limitations, and their relationship to NOSs. This chapter provides an overview of PCs, including the OS and computer networks. Microsoft Windows is detailed, from the beginnings of MS-DOS to the latest version of Windows, XP. The UNIX and Linux operating systems are also detailed, from their origins to the current configurations. Most network applications, including the Internet, are built around a client/server relationship. You will learn how this relationship works, along with the NOS s components and configurations.

3 4 Chapter 1: Operating System Fundamentals Operating System Basics This section covers the following topics: PC operating systems PCs and computer networks Operating system components: the kernel, the user interface, and the file system Common desktop operating systems Overview of PC Operating Systems Desktop microcomputers first became popular and widespread in the early 1980s. Users of these early desktop PCs put their systems to work performing a variety of tasks, including word processing, home accounting, and computer gaming. Desktop PCs also appeared in the workplace, but their productivity was limited by their inability to share information easily with other systems. Figure 1-1 shows how these early desktop PCs were electronic islands, unable to efficiently communicate with other PCs and the powerful mainframes and minicomputers that housed mission-critical data. Figure 1-1 Mainframe Computer Mainframe Dumb Terminals For the most part, the operating systems of these early desktop PCs were designed for the standalone system. These operating systems assumed that only one user would access system resources at any given time. The concepts of file security and user privileges were not necessarily built in to desktop operating systems, because only one user could access the system at a time, and that user had to be physically present at the keyboard.

4 Operating System Basics 5 PCs and Computer Networks As desktop computing matured in the workplace, companies installed local-area networks (LANs) to connect desktop PCs so that the PCs could share data and peripherals, such as printers. Installing network adapter cards in the PCs and then connecting the adapters using copper wire created LANs. Networking computers solved the problem of efficient communication, but new problems arose. Early PC-based LANs needed a way to provide file security, multiuser access to resources, and user privileges. PC-based LANs also needed a way to communicate with the mainframes that were still the focal point of corporate computing environments. One approach to solving these problems was to develop operating systems that were specialized to work in a networked environment. These so-called network operating systems (NOSs) required more computing muscle than their desktop counterparts. A new breed of powerful PCs was pressed into service as network servers. These computers ran NOSs and became the focal point of the PC-based LAN. In a server-based network, client machines connect to and access resources on the server. These client machines can run desktop operating systems, and the more powerful servers use a NOS. Software companies such as Novell and Microsoft designed their NOSs to control PC-based network environments. As network servers became more powerful, they began to take on the functions once handled by mainframes and minicomputers. Companies such as Sun and HP modified the UNIX operating system to run extremely powerful servers. In the past, only expensive mainframes and minicomputers were trusted with mission-critical applications and data storage. But like the Novell and Microsoft NOSs, UNIX could run on microcomputers. Today, virtually all organizations rely (at least in part) on microcomputers to store mission-critical data and provide key applications and services. Computer networking is not confined to the workplace. Most home users expect to connect to the largest network in the world, the Internet. Web browsing, , and other Internet-related applications are now the focus of home computing. To provide these Internet technologies, companies such as Microsoft have retooled their desktop operating systems. The desktop OS now includes many of the features and services that were once reserved for NOSs. Figures 1-2, 1-3, and 1-4 show the evolution of networking.

5 6 Chapter 1: Operating System Fundamentals Figure 1-2 Standalone Devices Client Workstations Workstation Printer Client Workstations Figure 1-3 Networked Devices Client Workstations Hub Workstation Printer Client Workstations Figure 1-4 Mainframe Integration Network Server Switch Mainframe Client Workstations

6 Operating System Basics 7 Operating System Components Whether designed for a standalone desktop computer or a multiuser network server, all operating system software includes the following components: Kernel User interface File system Kernel Kernel is the most common term for the core of the operating system. The kernel is a relatively small piece of code that is loaded into memory when the computer boots. This computer code contains instructions that allow the kernel to manage hardware devices, such as disk drives. The kernel also manages and controls memory allocation, system processes, and other programs. Application software and other parts of the operating system rely on the kernel to provide basic scheduling services and access to the computer hardware and peripherals. With a UNIX or Linux system, a file named kernel might be present. In some cases, the kernel code might have to be customized and compiled. If this file were to become corrupted, the system would no longer function. On a Windows system, filenames that include the word kernel or kern, such as kernel32.dll, might be seen. These are critical files that are used by the OS s core. Figure 1-5 shows the kernel32.dll file and where it is located within the Windows core system files. User Interface The user interface (UI) is the most visible part of a computer operating system. The UI is the component of the OS that the user interacts with. It acts like a bridge between the user and the kernel. The UI is like an interpreter, translating user keystrokes, mouse clicks, or other input for the appropriate programs. The UI can organize and display program output. On a UNIX or Linux system, a UI is typically called a shell. User interfaces fall into two general categories: Figure 1-6 shows an example of the Windows command-line interface (CLI). Figure 1-7 shows an example of the Windows graphical user interface (GUI).

7 8 Chapter 1: Operating System Fundamentals Figure 1-5 Windows 2000 Kernel File Figure 1-6 Command-Line Interface

8 Operating System Basics 9 Figure 1-7 Graphical User Interface The first desktop PC operating systems used CLIs exclusively. The CLI provides the user with a visual prompt, and the user inputs commands by typing them. The computer outputs data to the screen typographically. In other words, a CLI environment is completely text-based. The user can get things done only by inputting commands with the keyboard. UNIX and Linux users can choose from a variety of CLIs, or shells, such as the Bourne shell and the Korn shell. UNIX shells are discussed later in this chapter. Today, all popular desktop OSs support GUIs. A GUI allows the user to manipulate software using visual objects such as windows, pull-down menus, pointers, and icons. The GUI allows the user to input commands via a mouse or other point-and-click device. End users prefer a graphical interface, because it makes operating the computer easy and intuitive. A user can perform simple operations using a GUI without even knowing how to read. The trade-off for simplifying the user interface comes in performance. Some GUI software can consume more than 100 times the storage space that CLI software does. And because GUIs are more complicated than CLIs, GUI software requires significantly more memory and CPU time.

9 10 Chapter 1: Operating System Fundamentals Because the average end user prefers and expects a graphical interface when using a computer, GUIs are now considered a requirement for desktop OSs. However, NOSs have not traditionally catered to the needs of inexperienced users. Several NOSs do not fully support GUIs. Today, most NOSs support GUIs as separate modules that can be loaded and used just as any other program that runs on the system. Most NOSs do not require these GUI modules to function, but these modules make the NOS easier and more attractive to the inexperienced user and more available to the public. System administrators typically are comfortable working in CLI environments, so they might choose to preserve server resources by not loading the GUI software. For example, UNIX and Linux both support GUIs, but when deployed as NOSs, UNIX and Linux are often configured without GUI components. In contrast, Windows servers always include the GUI and therefore make heavier demands on system resources. File System An OS s file system determines how files are named and how and where they are placed on storage devices, such as hard disks. Windows, Macintosh, UNIX, and Linux OSs all employ file systems that use a hierarchical structure. In a hierarchical file system, files are placed in logical containers that are arranged in an upside-down tree structure, as shown in Figure 1-8. The file system starts at the tree s root. UNIX and Linux call a container residing at the top level of the tree a directory. Containers inside each directory are called subdirectories. Windows and Macintosh OSs use the terms folder and subfolder to describe directories and subdirectories. An OS s file system determines more than just how files and folders are logically organized. The type of file system the computer uses determines whether files can be secured from other users or programs. The file system also defines how data is physically arranged on the storage medium (such as a hard drive). Some file systems use disk space more efficiently than others. One common type of file system is called a file allocation table (FAT). FAT file systems are maintained on the disk by the operating system. The table contains a map of files and where they are stored on the disk. The FAT references disk clusters, which are the basic unit of logical storage on a disk. A given file may be stored on several clusters, but a cluster can contain data from only one file. These clusters might or might not be next to each other. The OS uses the FAT to find all the disk clusters where a file is stored.

10 Operating System Basics 11 Figure 1-8 File System There are the three types of FAT file systems. The original FAT file system is called FAT. The two other types, FAT16 and FAT32, are advanced and improved versions of the original FAT file system. The original FAT file system was used on the first versions of DOS. However, it couldn t be used with the larger hard disks and more-advanced operating systems such as Windows 3.1, Windows 95, and Windows 98. The original FAT file system was limited in various ways, such as recognizing filenames up to only eight characters long. Other limitations of FAT were that it was not be a viable option to use on the larger hard disks and more-advanced operating systems that were rapidly being developed. The original FAT file system could not make efficient use of space on these larger hard drives. This inefficient use of space was the same problem facing FAT16 and was a major reason why FAT32 was developed. FAT16 was created for use on larger partitions (up to 4 GB). Although larger disks can be formatted in FAT16, doing so is an inefficient use of disk space, because in the FAT file system, larger partitions result in larger cluster sizes. For example, with a 512 MB partition, the size of the clusters (that is, the basic storage units) is 8 KB. This means that even if a file is only 1 KB in size, it uses 8 KB of space, because more than one file cannot be stored in a cluster; the extra 7 KB is wasted.

11 12 Chapter 1: Operating System Fundamentals To overcome this problem, FAT32 was developed. This 32-bit file system uses smaller cluster sizes on large disks. It supports partitions up to 2 terabytes (TB) in size. Table 1-1 shows the file systems of operating systems. Table 1-1 Operating Systems and Their File Systems Operating System DOS Windows 3.x Windows 95/98/Me Windows NT/2000 Windows XP IBM OS/2 Linux Supported File System(s) FAT FAT16 FAT16, FAT32 FAT16, FAT32, NTFS FAT32, NTFS High-Performance File System (HPFS) Ext2, Ext3, Journaling File System (JFS) Different operating systems use different file systems, and some operating systems can use more than one file system. For example, although Windows 3.x can use only the FAT16 file system, Windows 2000 can use FAT16, FAT32, or the New Technology File System (NTFS). The file system determines file-naming conventions and the format for specifying a path, or route, to the file location. These rules for naming files vary depending on the file system and include several issues: Maximum number of characters allowed in a filename Maximum length of file extensions or suffixes Whether spaces are allowed between words in a filename Whether filenames are case-sensitive Which characters are legal for use in filenames Format for specifying the path Common Desktop Operating Systems Over the past 20 years, desktop operating systems have evolved to include sophisticated GUIs and powerful networking components, as shown in Figure 1-9.

12 Operating System Basics 13 Figure 1-9 Desktop Operating Systems Microsoft Disk Operating System (MS-DOS) is an obsolete OS that is still used to support legacy business applications. Windows versions prior to Windows 95 were essentially user interfaces for DOS. Microsoft Windows includes Windows 95, 98, Me, NT, 2000, and XP. Apple Macintosh OS (Mac OS) includes OS 8, OS 9, and OS X (OS 10). Linux includes distributions from various companies and groups, such as Red Hat, Caldera, Santa Cruz Operation (SCO), SuSE, Slackware, Debian, and others. UNIX includes HP-UX, Sun Solaris, Berkeley System Distribution (BSD), and others. Today, OS developers and users alike recognize that the Internet is at the center of computing, confirming the Sun slogan, The network is the computer. Because networking and the Internet have become such an integral part of using a computer, the desktop operating system is rapidly converging with the network operating system. Microsoft Windows and MacOS can trace their roots to early desktop PCs. The latest versions of these OSs have powerful NOS components at their core. Windows XP is built on Microsoft NOS technology (NT and 2000), and MacOS is built around UNIX. UNIX is considered the first NOS. And like UNIX, the information technology (IT) industry has always considered Linux a NOS first and a desktop operating system second.

13 14 Chapter 1: Operating System Fundamentals Are Windows, Linux, and UNIX desktop software or network server software? The answer to that question depends on several factors, including the specific OS version, the components installed, and the system configuration. In the following sections, Microsoft Windows and Linux are discussed as desktop operating systems. Windows 2000 and Linux are discussed in terms of NOSs later in this course. Worksheet Operating Systems Basics This covers some of the basic topics universal to all operating systems and the types of files systems supported in various operating systems that are covered in this course. Microsoft Windows This section covers the following topics: MS-DOS Windows 3.1 Windows 9x Windows NT and Windows Windows XP Windows GUI Windows CLI Windows Control Panel MS-DOS Microsoft released its first Windows product, Windows 1.0, in Figure 1-10 shows what the user interface looked like in this first version of Windows. Windows 2.0 was released in The earliest versions of Windows functioned as graphical user interfaces that ran on top of the native OS, which was called the Disk Operating System (DOS). Windows was a shell that allowed the user to manage the underlying DOS software.

14 Microsoft Windows 15 Figure 1-10 Windows 1.0 The Microsoft version of DOS (MS-DOS) was built on an OS called 86-DOS or Quick and Dirty Operating System (QDOS). Seattle Computer Products wrote QDOS to run on the Intel 8086 processor. IBM used the 8088 processor, a less-expensive version, in its new line of PCs. Microsoft bought the rights to QDOS and released MS-DOS in Figure 1-11 shows the MS-DOS user interface. Figure 1-11 MS-DOS

15 16 Chapter 1: Operating System Fundamentals MS-DOS began as a simple operating system with a text-based CLI. Designed to run on the 16-bit (8-bit data bus) Intel 8088 processor, MS-DOS was a 16-bit operating system, which could process only 16 bits (2 bytes) at one time. MS-DOS and 16-bit processing are obsolete in today s Internet-based and graphicallyoriented desktop environments. Today, 32-bit operating systems are standard, and a handful of 64-bit operating systems are available for systems that have 64-bit processors. However, many corporations and small businesses continue to rely on MS-DOS to run legacy business applications in the workplace. A legacy application is outdated software that remains in use due to a previous investment. Some companies have made a significant investment in computer hardware, software, and training, and they find that MS-DOS and its related applications still get the job done. There are several reasons for using MS-DOS: MS-DOS is a simple, low-overhead operating system Memory and processor requirements are very low. DOS runs readily on outdated hardware. MS-DOS is inexpensive Not only is the operating system itself inexpensive, but the cost of compatible hardware, as mentioned previously, also is low. MS-DOS is stable and reliable Because it is not a multitasking operating system (that is, it runs only one program at a time), there is no need to worry about the conflicts and crashes caused by shared memory addresses. MS-DOS is easy to learn and use Although it is not as intuitive as a GUI-based operating system, as soon as you master the command syntax, DOS is relatively simple to use. Many programs are available for MS-DOS Because it was a standard for many years, a large number of programs were written to run on DOS. Some companies continue to run the operating system because proprietary programs, customwritten for their business to run on MS-DOS, do not work properly on the newer operating systems. Of course, there are many disadvantages to continuing to use this old operating system. MS-DOS cannot run the sophisticated graphical programs written for modern 32-bit Windows operating systems. The MS-DOS FAT file system is insecure and illsuited for today s privacy-conscious multiuser environments. Networking with MS-DOS clients is problematic. In some cases, an MS-DOS user might be unable to connect to network resources that use long filenames (more than eight characters).

16 Microsoft Windows 17 Finally, the most obvious shortcoming of MS-DOS is its intimidating CLI. As the desktop PC evolved, Microsoft set out to address the limitations of MS-DOS, particularly the user interface. Windows 1.0 and 2.0 were the first step toward this goal. Windows 3.1 It was not until Windows 3.0 was released in 1990 that Microsoft established its user interface as a major force in the industry. In 1992, Microsoft released an upgrade to 3.0 called Windows 3.1. Shortly thereafter, Microsoft made available a free upgrade to Windows 3.1, called Windows This family of products is known collectively as Windows 3.x. Figure 1-12 shows the initial screen that appears when Windows 3.1 and Windows 3.11 boot up. Figure 1-12 Windows 3.x Running MS-DOS with Windows 3.x addresses many of the MS-DOS shortcomings. The Windows 3.x shell provides a GUI and supports cooperative multitasking, which allows users to run more than one program simultaneously. However, Windows 3.x still has significant disadvantages. Although multitasking is good, cooperative multitasking is not the best way to implement it. Also, Windows 3.x is a 16-bit operating system that does not provide the file security and built-in networking support that users now demand. Cooperative and Preemptive Multitasking Cooperative multitasking is an environment in which programs share memory addresses and exchange information. In a multitasked environment, applications share the use of the processor through a method known as time slicing. The application programs are written to give up the processor after a set amount of time so that other programs that are running simultaneously can use it. If the program is poorly written, it might monopolize the processor. If one program crashes, it might bring the other programs down.

17 18 Chapter 1: Operating System Fundamentals A more efficient form of multitasking first used in Windows 9x is called preemptive multitasking, now used by newer versions of Windows as well. The operating system controls the allocation of processor time, and 32-bit programs run in their own separate address spaces. With preemptive multitasking, an unruly program cannot take over the system, and if one program crashes, it does not affect the others. Figure 1-13 shows the Windows Task Manager for Windows You can see that all the processes and programs running on the system have their own Process ID (PID) number, which the operating system uses to distinguish between running processes. Figure 1-13 Windows Task Manager Networking with Windows 3.x MS-DOS and Windows 3.1 require that additional network client software be installed before you can connect to a network. Windows for Workgroups 3.1 (released in 1992) was the first Microsoft operating system to have networking components built in. Microsoft released Windows for Workgroups 3.11 in Windows for Workgroups was designed to allow users to share files with other desktop PCs in their workgroup. Figure 1-14 shows the network setup screen that is used to configure a Windows 3.11 system for network access. This kind of networking, in which every computer plays an equal role in the network, is called peer-to-peer networking. Built-in networking and peer-to-peer capabilities were important additions

18 Microsoft Windows 19 to Windows, but other operating systems, such as Apple Macintosh OS, provided peer-to-peer networking long before Windows for Workgroups. Figure 1-14 Windows for Workgroups 3.11 Today, Windows 3.x is considered obsolete. More recent versions of Windows offer significant advantages, including improved networking. Windows 3.x and MS-DOS can be used to connect to a modern Windows NT or Windows 2000 network, but in such cases, Windows 3.x clients are likely to receive limited services. Windows 9x Microsoft Windows 95 was designed for easy networking, and the tradition was carried on and enhanced in Windows 98. These operating systems are collectively called Windows 9x. Figure 1-15 shows an example of the Windows 9x desktop with the taskbar, which was a new feature that was added to the Windows 9x family of operating systems. Figure 1-15 Windows 9x

19 20 Chapter 1: Operating System Fundamentals Some of the other new features that were added to Windows 9x operating systems are listed here and in Table 1-2: Windows 95a The original release of the first Microsoft 32-bit desktop operating system. Windows 95b Also called OSR2. It included enhancements such as FAT32 support but was made available only to Original Equipment Manufacturers (OEMs) for installation on the computers they sold. Windows 98 An upgrade to Windows 95 that added the Active Desktop technology, the Advanced Configuration and Power Interface (ACPI), support for the Universal Serial Bus (USB) and TV-tuner cards, and setup and maintenance enhancements. Windows 98 Second Edition (SE) Provided the Internet Explorer 5.0 web browser, stronger encryption for dialup networking, and added support for Internet Connection Sharing (ICS). Windows Millennium Edition (Windows Me) An OS targeted specifically at home users. Because it builds on the Windows 9x code, Windows Me is generally recognized as part of the 9x family. Windows Me includes the following features: Enhanced multimedia support, making it easy to work with movies and digital photos Built-in disaster recovery features that let you restore the system to a predetermined state Simplification of the configuration required to set up simple peer-to-peer networks Faster startup and shutdown (when using new hardware that supports the FastBoot technology) Table 1-2 Versions of Windows 9x Version Features Windows 95a 32-bit OS, improved interface over Windows 3.x Windows 95b Windows 98 Windows 98 SE (Second Edition) Windows Me (Millennium Edition) Added FAT32 support Active Desktop, ACPI, USB Internet Explorer 5.0, ICS Simplified and enhanced for home PCs, additional multimedia support, disaster recovery

20 Microsoft Windows 21 Networking with Windows 9x The Windows 9x operating systems include specialized networking client software. Client software allows the OS to participate in server-based networks. Clients take advantages of services that are offered by systems running NOS software, such as Windows NT or Novell Netware. These services include authentication, file sharing, printer sharing, directory/naming services, mail service, and web services. Windows 9x includes client software for a variety of networks. Because of its connectivity features, Windows 9x is one of the most popular client operating systems in the business world. For several years, it has been the desktop operating system of choice for both small and large companies, for peer-to-peer networks, and for use as a client to Microsoft NT, NetWare, and UNIX servers. 32-Bit Processing and Preemptive Multitasking Windows 9x supports 32-bit applications, but it also includes 16-bit code for backward compatibility with DOS and Windows 3.x programs. It uses Virtual File Allocation Table (VFAT) for long filename support, and Windows 95b and 98 can use FAT32 for more efficient disk use. Some advantages of Windows 9x as a desktop operating system and network client include the following: It is less expensive than Windows NT and Windows It runs a wide variety of DOS, 16-bit, and 32-bit Windows applications. Its interface is familiar to most PC users. Client software is available for Windows 9x to connect to most NOS types, such as Windows, NetWare, UNIX, and Linux. Windows NT and Windows 2000 In the 1990s, Microsoft began developing an operating system that would meet the needs of a modern networked environment. The result was Windows NT. The NT stood for New Technology. Microsoft first released NT as version 3.0 in Windows NT 4.0 was released in Windows NT ran on an entirely new kernel. It did not rely on the old DOS-related code that other versions of Windows had been built on. The Windows NT software featured improved file security, stability, networking, and 32-bit support. To that end, Windows NT supported a new file system called NTFS. From the start, Microsoft positioned Windows NT as an operating system for highend servers and power users. Windows NT was the first Microsoft NOS.

21 22 Chapter 1: Operating System Fundamentals Because of NT s superior features, Microsoft planned to unite its desktop OS (Windows 9x) with its NOS (NT) as a new family of products called Windows NT 5.0. The NT 5.0 project was eventually dubbed Windows 2000 after the year in which it was finally released. Despite Microsoft s original intention to release a home user version of the software, Windows 2000 has remained an OS for power users, corporate desktops, and high-end servers. Figure 1-16 shows a timeline of the Windows operating systems from NT 3.1 to the release of Windows Figure 1-16 From Windows NT to 2000 August 1993 Windows NT 3.1 September 1994 Windows NT 3.5 June 1995 Windows NT 3.51 August 1996 Windows NT 4.0 September 1997 Windows NT 5.0 Beta 1 December 1997 Windows NT 4.0 Option Pack August 1998 Windows NT 5.0 Beta 2 April 1999 Windows 2000 Beta 3 July 1999 Windows 2000 Release Candidate 1 September 1999 Windows 2000 Release Candidate 2 February 2000 Windows 2000 Windows XP Windows XP was released in It represents the first OS built on NT that was directly targeted toward home, as well as corporate, desktops. The Windows XP family is as follows: Windows XP Targeted for home users Windows XP Pro Targeted for power users and the corporate desktop Windows.NET server Targeted for servers as a NOS Although Windows XP and XP Professional share many components with their NT/ 2000 ancestors, they are still considered desktop operating systems. Despite this semantic distinction, Windows XP and XP Professional offer many of the key features associated with a NOS, including sophisticated file security and resource sharing, support for multiple user accounts, remote administration, and numerous networking components and services. Both Windows XP Home Edition and XP Professional support

22 Microsoft Windows 23 multiple user accounts, but only Windows XP Professional supports remote access. Figures 1-17, 1-18, and 1-19 show how different the Windows XP GUI is from the Windows 2000 GUI. Figure 1-17 Launching Windows XP Figure 1-18 Logging on to Windows XP

23 24 Chapter 1: Operating System Fundamentals Figure 1-19 Windows XP Windows GUI The Windows GUI is perhaps the most recognizable user interface in the world. The Windows 9x, NT, 2000, and XP operating systems all share common elements in their GUIs. Figure 1-20 points out many of these similar features that all these versions of Windows have in common: Desktop Windows taskbar Start menu My Computer icon Network Neighborhood (also known as My Network Places) Recycle Bin Figure 1-20 Elements of the Windows GUI

24 Microsoft Windows 25 When you use the Windows GUI, right-clicking the My Computer icon and selecting Properties from the popup menu lets you check what version of Windows is currently installed in the system. The version of the OS software is displayed on the General tab of the System Properties window. Figure 1-21 shows an example of this window where the Windows version is displayed. Figure 1-21 Windows Version Windows CLI All Windows operating systems include a command-line environment that lets you enter common MS-DOS commands. Figure 1-22 shows an example of the MS-DOS CLI interface.

25 26 Chapter 1: Operating System Fundamentals Figure 1-22 Command Prompt Window NOTE With Windows NT, 2000, and XP machines, enter cmd instead of command to open a DOS box. To access the command line in Windows 9x, select Run from the Start menu and enter command, in the Run dialog box. This opens a window commonly called a command prompt. At the prompt, you can enter text-based commands and run programs. Output in the DOS box is also text-based. Table 1-3 lists some common Windows CLI commands. Table 1-3 Common Windows CLI Commands Command dir cd directory name time date copy diskcopy [source][destination] attrib find text string help Result Lists the files in the current directory Changes to a different directory Displays or sets the system time Displays or sets the system date Copies files to another location Copies the contents of one floppy disk to another Displays or changes file attributes Searches for a text string in a file Displays a list of other available commands and their functions

26 Microsoft Windows 27 Windows Control Panel The Windows GUI includes an important configuration tool called the Control Panel. The Windows Control Panel is a central location for making system configuration changes. Figure 1-23 shows an example of the various configuration tools that are available in the Control Panel. Figure 1-23 Windows 2000 Control Panel From the Control Panel, a user can perform the following key tasks: Install and remove hardware drivers Install and remove software applications and other components Add, modify, and delete user accounts Configure an Internet connection Configure peripheral device settings (modem, mouse, printer, and so on) Worksheet Microsoft Windows Basics This worksheet covers the fundamental aspects of Microsoft Windows.

27 28 Chapter 1: Operating System Fundamentals UNIX and Linux on the Desktop This section covers the following topics: Origins of UNIX Origins of Linux Linux/UNIX GUI Linux/UNIX CLI Linux and UNIX system configuration tools Origins of UNIX UNIX is the name of a group of operating systems that trace their origins to 1969 at Bell Labs. UNIX was designed to support multiple users and multitasking. UNIX was also one of the first operating systems to include support for Internet networking protocols. The history of UNIX, which now spans more than 30 years, is complicated, because many companies and organizations have contributed to its development. During the 1970s, UNIX evolved through the development work of programmers at Bell Labs and several universities, notably the University of California at Berkeley. When UNIX first started to be marketed commercially in the 1980s, it was used to run powerful network servers, not desktop computers. Today, there are dozens of different versions of UNIX, including the following: HP-UX (Hewlett-Packard s UNIX) Berkeley Software Design, Inc. (BSD UNIX, which has spawned derivatives such as FreeBSD) Santa Cruz Operation (SCO) UNIX Sun Solaris AIX (IBM s UNIX) Despite the popularity of Microsoft Windows on corporate LANs, much of the Internet runs on powerful UNIX systems. Although UNIX is usually associated with expensive hardware and is considered user-unfriendly, recent developments, including the creation of Linux (described in the next section), have changed that image. Table 1-4 shows some of the various types of servers that UNIX and Linux systems are used for.

28 UNIX and Linux on the Desktop 29 Table 1-4 Popular Network Uses of UNIX and Windows Operating System UNIX Linux Popular Uses Web servers FTP servers DNS servers Firewalls Large file servers Client workstations Corporate file servers Low-scale web servers Origins of Linux In 1991, a Finnish student named Linus Torvalds began work on an operating system for an Intel based computer. Frustrated with the state of desktop operating systems such as DOS, and the expense and licensing issues associated with commercial UNIX, Torvalds set out to develop an operating system that was UNIX-like in its operation but used software code that was open and completely free. Although it was not his original intent, Torvalds work led to a worldwide collaborative effort to develop Linux, an open-source operating system that looks and feels like UNIX. By the late 1990s, Linux had become a viable alternative to UNIX on servers and Windows on the desktop. Figure 1-24 shows a timeline of the major developments made with the Linux operating system. The popularity of Linux on desktop PCs has also contributed to interest in using UNIX distributions, such as FreeBSD and Sun Solaris, on the desktop. Versions of Linux can now run on almost any 32-bit processor, including the Intel 80386, Motorola 68000, Alpha, and PowerPC chips. Figure 1-24 Linux Development Timeline

29 30 Chapter 1: Operating System Fundamentals As with UNIX, there are numerous versions of Linux. Some are free downloads from the web, and others are commercially distributed. The following are a few of the most popular: NOTE Although UNIX is more often implemented as a server operating system, UNIX machines can also function as network clients. In many cases, the configuration and commands for UNIX are the same as they are in Linux systems. However, because both UNIX and Linux come in many different versions, the instructions in the following sections might not apply to every distribution of UNIX or Linux. Generally, use the man command to access the manual for the specific version being used. Red Hat Linux, distributed by RedHat Software OpenLinux, distributed by Caldera Corel Linux Slackware Debian GNU/Linux SuSE Linux Linux is one of the most powerful and reliable operating systems in the world today. Because of this, Linux has already made inroads as a platform for power users and in the enterprise server arena. It is less often deployed as a corporate desktop operating system. Although GUI interfaces are available to make it user-friendly, most beginning users find Linux more difficult to use than MacOS or Windows. Currently, many companies (such as Red Hat, SuSE, Corel, and Caldera) are striving to make Linux a viable operating system for the desktop. Application support must be considered when Linux is implemented on a desktop system. The number of business productivity applications is limited when compared to Windows. However, some vendors provide Windows emulation software (such as WABI and WINE) that lets many Windows applications run on Linux. Additionally, companies such as Corel are making Linux versions of their office suites and other popular software packages. Networking with Linux Recent distributions of Linux have networking components built in for connecting to a LAN and establishing a dialup connection to the Internet or another remote network. In fact, TCP/IP is integrated into the Linux kernel instead of being implemented as a separate subsystem. Here are some advantages of Linux as a desktop operating system and network client: It is a true 32-bit operating system. It supports preemptive multitasking and virtual memory. The code is open-source and thus is available for anyone to enhance and improve. In this chapter, UNIX and Linux are discussed together because of their superficial similarities. Later chapters explain the differences between these two operating systems.

30 UNIX and Linux on the Desktop 31 Linux/UNIX GUI Both UNIX and Linux can run GUIs. Because there are so many different versions of both UNIX and Linux, there are literally dozens of popular graphical interfaces to choose from. For example, the default installation of Red Hat 7.x installs the GNOME desktop environment and uses GNOME as the default GUI for all users (see Figure 1-25). Figure 1-25 GNOME Desktop Environment Although other desktop environments, such as the K desktop environment (KDE) (shown in Figure 1-26), can be configured and used with Linux, GNOME is rapidly gaining industry acceptance as a standard UNIX and Linux GUI. Figure 1-26 KDE Desktop Environment

31 32 Chapter 1: Operating System Fundamentals UNIX and Linux both rely on the X Window System to display the GUI. The X Window System is software that works with the system s hardware and graphical applications, including the window manager. The window manager is the software responsible for sizing, positioning, and rendering the graphical windows that programs run in. Windows includes borders that you can drag to resize and graphical buttons that you can click to minimize, maximize, restore, and close the window. Because Linux supports dozens of window managers, and each window manager can be customized, there is no one way a window looks or acts. Table 1-5 lists some common window buttons and their functions. Table 1-5 Common Linux GUI Windows Controls Windows Button Function NOTE GNOME stands for GNU Network Object Model Environment and is pronounced guh- NOME. GNU stands for GNUs, not UNIX. GNU is a software project devoted to producing free open-source software for Linux. GNU is pronounced guh-new, which is why GNOME is pronounced with a g sound. Despite this, it is acceptable to pronounce GNOME as NOME. GNOME is not a window manager. In fact, GNOME can work with several different kinds of window managers. GNOME is a desktop environment. A desktop environment is a combination of programs, applications, and applets that make up part of the GUI. GNOME provides the following: Minimizes a window. You can restore a minimized window by clicking its title on the taskbar (the taskbar is part of the panel). Maximizes a window. Closes a window. If the window contains an application running in the foreground, this option terminates the application. Graphical panels that can be used to start applications or display status A graphical desktop that can be used to place applications, files, and menus A standard set of desktop tools and applications A set of conventions that let applications work together Linux/UNIX CLI UNIX and Linux were designed to be extremely flexible and customizable. As a result, UNIX and Linux support dozens of user interfaces. The most common are the textbased interfaces called shells.

32 UNIX and Linux on the Desktop 33 Users type commands that are interpreted by the shell, which in turn relays the user instructions to the operating system and other programs. UNIX (and Linux) shells are difficult to learn because they rely on abbreviations and complex command syntax. Commonly used shells include the following: Bourne shell Korn shell Bash shell C shell TC shell The distribution and configuration of the PC running UNIX or Linux determine the shells that are available to users. Although dozens of GUIs are available for UNIX and Linux, the CLI environment is the only user interface available on many systems. If a UNIX or Linux GUI is being used, there might be several ways to access a CLI shell, such as opening a terminal window, or term. You can enter the UNIX command uname on most systems to find out what version of UNIX or Linux a computer is running. Linux and UNIX System Configuration Tools The various versions of UNIX and Linux offer a variety of configuration tools, similar to the Windows Control Panel. Some of these tools are text-based, for CLI environments. Others, such as linuxconf for Linux and admintool for Solaris, can be used in the GUI. Figures 1-27 and 1-28 show examples of the two main GUI configuration tools that are used with Linux and UNIX. Figure 1-27 Linux GUI Tools: linuxconf

33 34 Chapter 1: Operating System Fundamentals Figure 1-28 Solaris GUI Tools: admintool Using these configuration utilities, you can perform the following key tasks: Add, modify, and delete user accounts Configure an Internet connection and network services Configure peripheral device settings (modem, mouse, printer, and so on) Worksheet UNIX and Linux on the Desktop This worksheet covers the fundamental aspects of UNIX and Linux. Network Operating Systems Overview This section covers the following topics: Common network operating systems The client/server model Evaluating customer resources and requirements Common Network Operating Systems The limitations of early desktop OSs and the increasing demand to network PCs led to the development of more-powerful NOS software. In contrast to early desktop PC software, NOSs provide built-in networking components and network services, multiuser capability, and sophisticated file security and file-sharing technologies. NOSs must have a robust kernel to prevent crashes and downtime. It is especially important that the NOS kernel schedule and manage multiple processes so that each program is prevented from crashing other parts of the system. Because specialized administrators manage NOSs, they do not necessarily require resource-consuming graphical interfaces. NOSs have historically offered less-than-

34 Network Operating Systems Overview 35 friendly user interfaces, especially when compared to their desktop counterparts. However, both Windows 2000 and Linux support fully featured GUIs and even webbased controls. Finally, a NOS requires a sophisticated file system that allows for efficient storage and maximum security. Instead of FAT, a NOS typically employs NTFS, UFS (UNIX file system), or another equally robust file system. Novell s NetWare was the first NOS to meet these requirements and enjoy widespread deployment in PC-based LANs in the 1980s. Since that time, Novell s software has lost its position as the top PC-based NOS. Common NOSs in use today include those covered in the following sections. Microsoft Windows Figures 1-29 and 1-30 show examples of various Windows operating systems. Other types of NOSs offered by Windows are NT 3.51, NT 4.0, 2000, XP, and.net. Keep in mind that NT 3.51 and NT 4.0 are being phased out as a result of the superior Windows 2000, XP, and.net. Figure 1-29 Windows XP

35 36 Chapter 1: Operating System Fundamentals Figure 1-30 Windows 2000 Novell NetWare Figures 1-31 and 1-32 show examples of the Novell line of operating systems, which include NetWare 3.12, IntraNetWare 4.11, and NetWare 5.0 and 5.1. Figure 1-31 Novell Login Box Figure 1-32 Novell Desktop

36 Network Operating Systems Overview 37 Linux Figures 1-33 and 1-34 show various examples of Linux operating systems, including Red Hat, Caldera, SuSE, Debian, and Slackware. Figure 1-33 Red Hat Linux Figure 1-34 Caldera Linux UNIX Figures 1-35 and 1-36 show some examples of the various operating systems offered by UNIX, such as HP-UX, Sun Solaris, BSD, SCO, and AIX.

37 38 Chapter 1: Operating System Fundamentals Figure 1-35 Sun Solaris Figure 1-36 BSD UNIX Project Client/Server Model Most network applications, including Internet-related applications such as the World Wide Web and , are built around a client/server relationship. A specialized program called a server offers network services such as to other programs called clients. (Server programs are typically called daemons in the UNIX community.) After it is enabled, a server program waits to receive requests from client programs. If a legitimate request is received, the server responds by sending the appropriate information back to the client. Figure 1-37 demonstrates how this interaction works.

38 Network Operating Systems Overview 39 Figure 1-37 Client/Server Interaction Information Request HTTP Service Telnet Service Remote Clients Service Request NOS Server FTP Service Apps Service For example, as soon as a web server program is run, it waits for client requests. A web browser is an example of a client program. Web browsers send requests to web servers. When the browser requests data from the server, the server responds, and the browser program receives a reply from the web server. The browser then displays the Hypertext Transfer Protocol (HTTP) data it received in its window. In theory, any computer can act as a server as long as it is connected to the network and is configured with the appropriate software. In practice, most organizations put all their key network services on high-end computers called servers running NOSs optimized for servicing remote clients. Figure 1-38 shows a typical logical arrangement of how servers would be placed in a network. A typical server running a NOS can be configured to offer literally hundreds of services to clients. Moreover, most NOSs can communicate with various kinds of client platforms by following a universally understood set of rules or protocols. The Internet is built around a set of rules collectively known as Transmission Control Protocol/Internet Protocol (TCP/IP). Because of the importance of the Internet, the majority of network services and client programs use TCP/IP to exchange data. However, other protocols, such as Novell IPX, Apple AppleTalk, and IBM SNA, are still used today. Most NOSs can be configured to communicate using one or more of these protocols as well as TCP/IP. One server running a NOS might work well when serving only a handful of clients. But most organizations find that they must deploy several servers to achieve acceptable performance. A typical design separates services so that one or two servers are responsible for , another server is responsible for file sharing, and so on. High-end servers running a NOS are typically configured to use the Internet family of protocols, TCP/IP, and offer one or more TCP/IP services. Servers running a NOS are also used to authenticate users and provide access to shared resources.

39 40 Chapter 1: Operating System Fundamentals Figure 1-38 Server Farm Firewall 100 Mbps Switch Web Server 1 Web Server 2 Web Server 3 Web Server 4 QC Server POCONS Server 100 Mbps Switch Database Server 1 Database Server Mbps Switch Admin, RAS, Monitoring Server Computer Evaluating Customer Resources and Requirements One of the first things you must consider when buying or building a new computer are the requirements that are needed to allow the system to efficiently provide the service. Determining the customer s resources also helps you decide what type of system to build or buy for the customer. Most computers that are sold are not designed to have Linux run on them. Therefore, evaluating certain requirements such as hardware and software helps in every other step of configuring Linux for the system. Other requirements, such as determining whether the system will be a workstation, server, or dedicated appliance, also help with subsequent steps of configuring Linux on the system. Careful planning of this step helps when you tackle other issues, such as installation, configuration, and administration (which are covered later in this course).

40 Network Operating Systems Overview 41 Workstations A Linux workstation, which is also known as a desktop computer, is a system that is typically a standalone computer consisting of one monitor, keyboard, and mouse. Most often a workstation is configured with a network connection as well, but this is not a requirement for a workstation or desktop computer. Figure 1-39 shows an example of a typical workstation that Linux can run on. Figure 1-39 Linux Workstation When evaluating the proper requirements for a Linux workstation, you must keep in mind that this system is used by an individual who needs to have specific hardware and software installed on the system. For example, a low-end system, which an individual might need for only simple tasks, such as word processing, does not need a very fast CPU or large amounts of memory and hard disk space. However, the requirements for a high-end system that an individual needs to do more-complex tasks, such as video editing or heavy-duty scientific simulations, are much greater. In fact, this high-end system needs to have a very fast processor as well as large amounts of memory and hard disk space. Other hardware requirements that typically are found on workstations are audio hardware such as a sound card and speakers. In some cases, a microphone might be needed as well. On a workstation you might also need some high-capacity removable media drives. These drives can be either zip drives or CD-R or CD-RW burners, and in some cases a DVD-ROM drive as well. Servers The requirements for a server are very different from those for a workstation. Figure 1-40 shows what a typical Linux server might look like. As you can see, servers generally look very different from workstation systems. Servers really have no need for user-

41 42 Chapter 1: Operating System Fundamentals oriented features such as large monitors, speakers, or a sound card. Servers need to consist of things such as very reliable and fault-tolerant hard disks. For this reason, servers have large, high-performance hard disks such as SCSI disks, as opposed to EIDE disks that would be installed in a workstation. This is because most servers make heavy use of their hard disk and therefore require disks that perform better. SCSI disks provide these features and are especially useful when multiple disks are installed on a single server. Figure 1-40 Server The size of the network that the server will support helps determine the server s CPU and memory requirements. For example, if you re installing a server in a large network environment that will handle a lot of requests and services, having a system with a fast CPU and a large amount of RAM is a necessity. This is not the case for a server that is in a small office that handles requests from a few users. With a Linux server, having large amounts of RAM can be more important, because the server has a feature that automatically stores in memory recent accesses to the hard disk. Therefore, Linux can read right from memory rather than going back to the hard disk when subsequent requests come in. This is called buffering disk access. For this reason, a Linux server with a lot of RAM can outperform a server with the same setup and less RAM. Another aspect to look at when determining requirements is what type of server this system will be. Determining whether this server will be a web or FTP server, Usenet news server, database server, or time server is a pertinent consideration. For example, if the server will handle a web site that will be accessed numerous times and provide many services, you need to design a very powerful server. In some cases, you might need to have more than one server providing the web services.