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Module 1

Module 1. Operating System Fundamentals. Computer Operating Systems. 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

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Module 1

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  1. Module 1 Operating System Fundamentals

  2. Computer Operating Systems • 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 • resource sharing among multiple users. • Today's most popular operating systems, such as Microsoft Windows 2000 and Linux, are found on high-powered network servers and on the desktops of end users.

  3. PC Operating Systems • Desktop microcomputers first became popular and widespread in the early 1980s. • Desktop PCs also appeared in the workplace, but their productivity was limited by their inability to share information easily with other systems. 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. • For the most part, the operating systems of these early desktop PCs were designed for the stand-alone system.

  4. PC Operating Systems • 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. • Early PC-based LANs needed a way to provide file security, multi-user access to resources, and user privileges. • One approach to solving these problems was to develop operating systems specialized to work in a networked environment. • Network operating systems were developed to facilitate communication between desktop PCs and servers.

  5. Operating Systems • Whether designed for a stand-alone desktop computer or a • multi-user network server, all operating system software • includes the following components: • Kernel • User Interface • File System

  6. The Kernel • The 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.

  7. The 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 acting 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. • User interfaces fall into two general categories: • Command-Line Interface (CLI) • Graphical User Interface (GUI)

  8. Command-Line 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. • A CLI environment is completely text-based and the user can only get things done by inputting commands with the keyboard. • The major advantage of CLI is that it requires less processing power to run. • Unix and Linux refer to CLI as a shell.

  9. Graphical User Interface • 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. • The tradeoff for simplifying the user interface comes in performance. Some GUI software can consume more than one hundred times the storage space that CLI software does.

  10. The File System • The file system of an OS determines the way 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. • The file system starts at the root of the tree. • UNIX and Linux call a container residing at the top-level of the tree a "directory."

  11. The File System • One common type of file system is called 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.

  12. The File System • 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

  13. File Allocation Table (FAT) • FAT16 and FAT32 are two types of FAT. • FAT16 was created for use on larger partitions (up to 4 GB). • Although larger disks can be formatted in FAT16, to do so is an inefficient use of disk space because in FAT, larger partitions result in larger cluster sizes. • FAT32 was developed to overcome the problems with FAT16. • FAT32s file system uses smaller cluster sizes on large disks. It supports partitions up to 2 terabytes (TB) in size.

  14. Operating Systems and Their File Systems

  15. Operating Systems • What are some examples of past and current operating systems?

  16. MS-DOS • MS-DOS began as a simple operating system with a text-based CLI. • MS-DOS was a 16-bit operating system, which could handle processing only 16-bits (2 bytes) at one time. • MS-DOS and 16-bit processing are obsolete in today's Internet-based and graphically-oriented desktop environments. • However, many corporations and small businesses continue to rely on MS-DOS to run legacy business applications in the workplace. • What is meant by “legacy applications?”

  17. Microsoft Windows • Microsoft Windows includes Windows • 3.x • 95 • 98 • ME • NT • 2000 • XP Windows 9x

  18. Apple Macintosh • Apple Macintosh OS (Mac OS) • OS 8 • OS 9 • OS X (OS 10)

  19. Linux • Linux includes distributions from various companies and groups • Red Hat • Caldera • Santa Cruz Operation (SCO) • SuSE • Slackware • Debian • Mandrake

  20. Unix • UNIX includes • HP-UX • Sun Solaris • Berkeley System Distribution (BSD)

  21. Multitasking • In a multitasked environment, applications share the use of the processor by a method known as "time slicing." • Cooperative multitasking is an environment in which programs share memory addresses and exchange information. (Windows 3.x) • Preemptive multitasking, first used in Windows 9x is a more efficient form of 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.

  22. Windows 9x • Microsoft Windows 95 was designed for easy networkability, and the tradition was carried on and enhanced in Windows 98. • These operating systems (plus Windows ME) are referred to collectively as Windows 9x.

  23. Windows NT • In the 1990s, Microsoft began developing an operating system that would meet the needs of a modern networked environment. The result was Windows NT. • 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.

  24. Windows XP • Windows XP was released in 2001 and represents the first OS built on NT that was directly targeted toward home, as well as corporate, desktops. • While Windows XP and XP Professional share many components with their NT/2000 ancestors, they are still considered desktop operating systems.

  25. Windows XP • 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 multiple user accounts but only Windows XP Professional supports remote access.

  26. Determining the Operating System • Using the Windows GUI, how can you determine the version on the operating system?

  27. Windows Command-Line • All Windows operating systems include a command-line environment that enables the user to enter common MS-DOS commands. • To access the command line in Windows 9x, select "Run" from the Start Menu and enter the word, command, in the Run dialog box. • How is this process different on a Windows NT, 2000, or XP system?

  28. Common Windows CLI Commands

  29. Windows Command-Line • 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.

  30. Unix • UNIX is the name of a group of operating systems that trace their origins back to 1969 at Bell Labs. • Since its inception, UNIX was designed to support multiple users and multi-tasking. • UNIX was also one of the first operating systems to include support for Internet networking protocols. • UNIX first started to be marketed commercially in the 1980s, it was used to run powerful network servers, not desktop computers.

  31. Linux • In 1991, a Finnish student named Linus Torvalds began work on an operating system for an Intel 80386-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. • By the late 1990s, Linux had become a viable alternative to UNIX on servers and Windows on the desktop.

  32. Linux • As with UNIX, there are numerous versions of Linux. The following are a few of the most popular: • RedHat Linux, distributed by RedHat Software • OpenLinux, distributed by Caldera • Corel Linux • Slackware • Debian GNU/Linux • SuSE Linux • Mandrake

  33. Linux / Unix GUI • Both UNIX and Linux are capable of running GUIs. Since there are so many different versions of both UNIX and Linux, there are literally dozens of popular graphical interfaces to choose from.

  34. Gnome Desktop • The default installation of Red Hat 7.x installs the GNOME Desktop Environment and uses GNOME as the default GUI for all users. GNOME is rapidly gaining industry acceptance as a "standard" UNIX and Linux GUI.

  35. KDE • K Desktop Environment (KDE) can be configured and used with Linux.

  36. Linux / Unix GUI • Linux and UNIX both rely on the X-Windows System to display the GUI. • The X-Windows System is software that works with the system hardware and graphical applications.

  37. Linux / Unix • 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 text-based interfaces called shells. • Commonly used shells include the following: • Enter the UNIX command, uname, on most systems to find out what version of the UNIX or Linux a computer is running. • Bourne shell • C shell • Korn shell • TC shell • Bash shell

  38. Linux / Unix GUI • The various versions of UNIX and Linux offer a variety of configuration tools similar to Windows Control Panel. Some of these tools are text-based, for CLI environments. Some of these tools, such as linuxconf for Linux or admintool for Solaris, can be used in a GUI.

  39. Windows and Linux NOS Comparison • These differences include • the modular aspect, which is still a fundamental component of Linux • text-mode interface functionality • cost • obtaining the OS (most systems come with Windows pre-installed) • ability to run from a CD (great for learning Linux) • available application software and obtaining application software • virus vulnerability • security features • supporting multiple users

  40. Network Operating Systems (NOS) • A NOS provides built-in networking components and network services, multiuser capability, and sophisticated file security and file sharing technologies. • A NOS must have a robust kernel to prevent crashes and downtime. • Because specialized administrators manage NOSs, they do not necessarily require resource-consuming graphical interfaces. • Finally, a NOS requires a sophisticated file system that allows for efficient storage and maximum security.

  41. Evaluating Customer Resources and Requirements   • Workstations • evaluate software and hardware needs • not all versions of Linux support drivers for hardware components • Servers • high-end hardware components (CPU, RAM) • no need for special monitors, keyboard, etc. • Factors to weigh if acting as a dedicated appliance • Cost • support

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