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Chapter Eight

Chapter Eight. Network Operating Systems and Windows 2000-Based Networking. Questions. What is a server? Hardware vs. software NOS installation can be trivial or complex NOS straddles Application layer and above on the OSI model Major types of NOS? What is all the fuss about Linux?.

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Chapter Eight

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  1. Chapter Eight Network Operating Systems and Windows 2000-Based Networking

  2. Questions • What is a server? • Hardware vs. software • NOS installation can be trivial or complex • NOS straddles Application layer and above on the OSI model • Major types of NOS? • What is all the fuss about Linux?

  3. Introduction to Network Operating Systems • Selecting a network operating system – things to consider: • Is it compatible with existing infrastructure? • Will it provide the security required by the network’s resources? • Can the technical staff manage it effectively? • Will existing applications run smoothly on it?

  4. Introduction to Network Operating Systems • Selecting a network operating system (cont.) • Will it accommodate future growth (that is, is it scalable)? • Does it support additional services the network’s users require? • How much does it cost? • What type of support can be expected from the manufacturer?

  5. Network Operating Systems and Servers • Determining Server Hardware: • How many clients will connect to the server? • What kind of applications will run on the server? • How much storage space will each user need? • How much down time is acceptable? • What can the organization afford? • Must consider processor (multiple?), RAM, storage requirements, fault-tolerance, & UPS • Cost can vary considerably - $2k to 100k • Compaq, Dell, IBM

  6. Network Operating System Services and Features • Networks enable client support in: • Creating client accounts and enabling them to connect to the network • Managing client accounts • Enabling clients to share resources • Managing client access to shared resources • Enabling clients to communicate with other clients

  7. Client/Server Communication • Redirector • Service that runs on a client workstation and determines whether the client’s request should be handled by the client or the server • Authentication (logon process) • Process whereby a network operating system verifies that a client’s user name and password are valid and allows the client to log onto the network

  8. Client/Server Communication Figure 8-1: A client connecting to a network operating system

  9. Client/Server Communication • Middleware • Software that sits between the client and server in a 3-tier architecture • Thin client • Type of software that enables a client to accomplish functions over a network while utilizing little of the client workstation’s resources and, instead, relying on the server to carry the processing burden

  10. Client/Server Communication Figure 8-2: Middleware between clients and a server

  11. Users and Groups • To more easily manage network access, you can combine users with similar needs and restrictions into groups Table 8-1: Providing security through groups

  12. Directories • Directory • List that organizes resources and associates them with other properties, or characteristics • Object • Representation of a thing or person associated with the network • Users, printers, groups, computers, data files, and applications • Attributes • Properties associated with an object • User object may have name, group membership, security settings, etc.

  13. Directories • Containers • Logically defined receptacles that serve only to assemble similar objects • Account • The record of a user that contains all of his or her properties • Tree • Logical representation of multiple, hierarchical levels in a directory

  14. Directories Figure 8-3: A directory tree

  15. Directories Figure 8-4: Two possible tree for the same organization

  16. File System • An operating system’s method of organizing, managing, and accessing its files through logical structures and software routines • Be careful not to confuse file systems with directories • A file system interacts with the operating system • A directory organizes files so that a user can find them on a hard disk

  17. FAT (File Allocation Table) • FAT (File Allocation Table) • Original PC file system designed in the 1970s to support floppy disks and, later, hard disks • FAT16 • File system designed for use with early DOS- and Windows-based computers • FAT32 • Enhanced version of FAT16 that accommodates the use of longer filenames and smaller allocation units on a disk

  18. Significant FAT16 Characteristics • Partitions or files cannot exceed 2 GB (when used with Windows 2000 file system, cannot exceed 4 GB) • Uses 16-bit fields to store file size information • Without additional utilities, supports only filenames with maximum of eight characters in the name and three in the extension

  19. Significant FAT16 Characteristics • Characterizes files on a disk as Read, Write, System, Hidden, or Archive • A FAT16 drive stores data in noncontiguous blocks and uses links between fragments to ensure that data belonging to the same file, for example, can be pieced together when the file is requested by the operating system • Because of its low overhead, it can write data to a hard disk very quickly

  20. Significant FAT32 Characteristics • Uses 28-bit fields to store file size information • Supports long filenames • Theoretically supports partitions up to 2 Terabytes in size • Partitions can be easily resized without damaging data • Provides greater security than FAT16 • Supported by Windows 9x, Windows Me, and Windows 2000

  21. HPFS • High-Performance File System • File system originally designed for IBM’s OS/2 operating system • Offers greater reliability and efficiency than FAT • Supports extended attributes • Ex. File history

  22. Sharing Applications • One significant advantage of the client/server relationship is the ability to share resources • Shared applications are often stored on a file server specifically designed to run applications • For some applications, you can purchase a site license • For a fixed price, a site license allows any number of users on one location to legally access that application

  23. Sharing Printers Figure 8-5: Shared printers on a network

  24. Sharing Printers • All NOSs can: • Create an object that identifies printer to rest of network • Assign printer a unique name • Install drivers associated with printer • Modify printer attributes • Establish or limit access to printer • Remotely test and monitor functionality • Update and maintain printer drivers

  25. Sharing Printers Figure 8-6: NetWare printer identification screen

  26. Sharing Printers • Printer queue • Logical representation of printer’s input and output Figure 8-7: Client issuing a job to a networked printer

  27. Managing System Resources:Memory • Physical memory • Refers to (RAM) chips installed on computer’s system board that provide dedicated memory to that machine • Virtual memory • Logically carved out of space on hard disk and added to physical memory • Stored on hard disk as a page file (or swap file) • Paging • Process of moving pages between RAM and into a page file on disk

  28. Managing System Resources:Multitasking • Multitasking • Ability of a processor to perform many different operations in a brief period of time • Preemptive multitasking • Type of multitasking supported by NetWare, UNIX, and Windows 2000 • Performs one task at a time

  29. Managing System Resources:Multiprocessing • Process • Routine of sequential instructions that runs until it has achieved its goal • Thread • Self-contained, well-defined task within a process • Multiprocessing • Support and use of multiple processors to handle multiple threads

  30. Managing System Resources:Multiprocessing • Symmetric multiprocessing • Splits all operations equally among two or more processors • Asymmetric multiprocessing • Assigns each subtask to a specific processor

  31. Introduction to Windows 2000 Server • Windows 2000 Server serves as a redesign and enhancement of Windows NT Server • Windows NT was a popular NOS known for its intuitive graphical user interface (GUI) • Windows 2000 Server carries on many of the advantages of Windows NT Server, plus provides additional features and capabilities (see next slide) • Windows 2000 Advanced Server offers same benefits and features as Windows 2000 Server, but adds support for clustering • Server – 4GB RAM & 4 processors • Advanced – 8GB RAM & 8 processors • Datacenter – 64GB RAM & 32 processors

  32. Some Benefits of Windows 2000 Server NOS • Advanced system of organizing and managing network objects, called Active Directory • Multiple, integrated Web services with easy to use administrator interface • Support for great deal of RAM and multiple processors • Support for multiple, modern protocols and security standards • Excellent integration with other NOSs • Simple, centralized management of multiple clients • Flexible, customizable network management interface

  33. Why Choose Windows 2000 Server? • Windows 2000 Server is a popular NOS because it addresses most of a network administrator’s needs very well • Its customizable graphical administrative interface called, the Microsoft Management Console (MMC), makes Windows 2000 Server a simple operating system to manage

  34. Windows 2000 Server Hardware • Important resource for determining what kind of Windows 2000 hardware to purchase is Microsoft’s Hardware Compatibility List (HCL) Table 8-2: Minimum hardware requirements for Windows 2000 Server

  35. Windows 2000 Server Memory Model Figure 8-8: Viewing virtual memory

  36. Windows 2000 File Systems • In addition to FAT, FAT32, and HPFS file systems, Windows 2000 Server supports other file systems, including: • CDFS (CD-ROM File System) • Used to read from and write to a CD-ROM disk • Universal Disk Format (UDF) • Another file system used on CD-ROM and DVD media • NTFS (New Technology File System) • Developed for Windows NT platform • With release of Windows 2000, Microsoft updated NTFS to version 5

  37. NTFS Features • Filenames can be maximum of 256 characters long • Stores file size information in 64-bit fields • Files or partitions can be as large as 16 exabytes • Required for Macintosh connectivity

  38. NTFS Features • Incorporates sophisticated, customizable compression routines • Keeps a log of file system activity to facilitate recovery if a system crash occurs • Required for encryption and advanced access security for files, user accounts, and processes • Improves fault tolerance through RAID and system file redundancy

  39. Microsoft Management Console (MMC) • Tools added to MMC interface are known as snap-ins Figure 8-9: MMC Window

  40. Active Directory • Schema • Set of definitions of kinds of objects and information associated with those objects that the Active Directory database can contain Figure 8-10: Active Directory and a simple user schema

  41. Active Directory • Active Directory’s schema may contain two types of definitions: • Classes • Also known as object classes • Identifies what type of objects can specified in Active Directory • Attributes • Property associated with an object

  42. Workgroups • Group of interconnected computers that share each other’s resources without relying on a central server Figure 8-11: A Windows workgroup network

  43. Domains • Group of users, servers, and other resources that share a database of account and security information Figure 8-12: Multiple domains in one organization

  44. Domains • Domain controller • Windows 2000 server that contains a replica of the Active Directory • Member server • Does not hold directory information and, therefore, cannot authenticate users • Replication • Process of copying Active Directory data to multiple domain controllers

  45. Domains Figure 8-13: A Windows 2000 domain model network

  46. Organizational Units • Container within an NOS directory used to group objects with similar characteristics or privileges Figure 8-14: A tree with multiple domains and OUs

  47. Trees and Forests • Domain tree • Group of hierarchically arranged domains that share a common namespace in Windows 2000 Active Directory • At base of Active Directory tree is the root domain • From root domain, child domains branch out to separate objects with the same policies • Forest • Collection of one or more domain trees

  48. Trust Relationships • Relationship between two domains in which one domain allows another domain to authenticate its users • Active Directory supports two types of trust relationships: • Two-way transitive trust • Explicit one-way transitive trust

  49. Two-Way Transitive Trust • Security relationship between domains in same domain tree in which one domain grants every other domain in the tree access to its resources and, in turn, that domain can access other domains’ resources Figure 8-15: Two-way trusts between domains in a tree

  50. Explicit One-Way Transitive Trust • Type of trust relationship in which two domains that belong to different NOS directory trees are configured to trust each other Figure 8-16: Explicit one-way trust between domains in different trees

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