Network Guide to Networks 5th Edition

1
Network Guide to Networks5th Edition

• Chapter 9
• Network Operating Systems

2
Objectives

• Describe characteristics common to all NOSs
  (network operating systems)
• Compare and evaluate NOSs to select the right one
  for your Network
• Define the requirements for and features of the
  Windows Server 2008 NOS
• Define the requirements for and features of UNIX
  and Linux NOSs
• Create users and groups and assign file
  permissions

3
NOS Characteristics

• Based on client/server architecture
• Manages resource sharing
• Provides many other functions
• NOS components vary by NOS version and type

4
NOS and Servers

• Questions to answer when determining optimal
  server hardware
• What kinds of applications will run on the
  server?
• How many clients will connect to the server?
• How much storage space will each user need?
• How much downtime, if any, is acceptable?
• What can the organization afford?
• Spend as much as necessary to get a reliable
  server!!

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3-Tiered Architecture
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Users and Groups

• Users
• Each person accessing network should be given
  his/her own user account
• Groups
• Basis for resource and account management
• Assists in resource sharing and security control
• Whenever possible, assign rights/privileges to
  groups, not individual users

7
Directory Services

• Modern NOSs use Directory Services
• Similar patterns for organizing information
• Users, printers, servers, data files, and
  applications
• Directory
• List organizing resources
• Associates resources with characteristics
• Example file system directory

8
LDAP

• Used to access information stored in directory
• MS Active Directory
• Novell NDS
• Uses Object-Oriented Database
• Object -- thing or person associated with network
• Attributes -- properties associated with object
• Schema -- set of definitions, specifying kinds of
  objects and object-related information contained
  in directory

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Sharing Applications

• Application licensing types
• Per user licensing
• Per seat licensing
• Site license
• NOS responsible for arbitrating file access
• Multiple users simultaneously accessing same data
  files, same program files, can be problematic

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Sharing Printers

• Increases resource management efficiency reduces
  costs
• Shared printing requires
• Print server
• Print queue
• Printer
• All NOSs perform common tasks in managing
  printers

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Sharing Printers (contd.)
12
System Resources

• Memory (physical/virtual)
• Processor(s)
• Storage (hard drive)

13
Memory

• Physical memory RAM (more better/faster)
• Virtual memory stored on hard drive
• Page file (paging file, swap file)
• Paging -- moving blocks into/out of virtual
  memory
• Advantages
• Easily expands memory available to server
  applications
• Engaged by default
• Disadvantage
• Slows operations

14
Multitasking

• Execution of multiple tasks at one time
• All modern operating systems do this
• Does not mean performing more than one operation
  simultaneously (it just seems that way)
• Preemptive multitasking
• OS is in charge of allocating processor cycles
• Crash of one application does not affect others
• Cooperative multitasking
• Applications are in charge of allocating
  processor cycles
• If one application crashes, the entire system
  halts.

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Multiprocessing

• Process -- routine of sequential instructions
  that runs until goal is achieved
• Thread -- Self-contained well-defined task
  within process
• One processor systems can handle only one thread
  at a time
• Multiprocessor systems can handle numerous
  tasks/threads simultaneously

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Multiprocessing

• Symmetric multiprocessing -- splits all
  operations equally among two or more processors
• Asymmetric multiprocessing -- assigns each
  subtask to specific processor

17
Windows Server 2008

• Released February 2008
• Enhancements of Windows Server 2003
• security
• reliability
• remote client support
• Performance
• New server management features

18
Server 2008s Memory Model

• Addressing schemes
• 32-bit addressing scheme
• 64-bit addressing scheme
• Assigns each application (process) its own
  32-bit memory area
• Uses virtual memory

19
NTFS

• Used on all Windows operating system versions
  since Windows NT
• Features
• Secure
• Reliable
• Compressible
• Incompatible with Windows 3x, 95, 98, ME

20
Workgroups

• Peer-to-peer network
• Decentralized management
• Each computer has own database
• User accounts, security privileges
• Significantly more administration effort
• Practical for small networks
• Few users
• Simple to design, implement

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Domains AD

• Domain
• Group of users, servers, and other resources
• Share centralized account and security
  information database
• Active Directory
• Contains one or more domain databases
• Easier to organize and manage resources and
  security

22
Domains AD
Figure 9-8 Multiple domains in one organization
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AD Naming Conventions

• Based on LDAP
• Internet namespace (DNS) maps hostnames to IP
  addresses
• Active Directory namespace maps AD object names,
  associated places
• These namespaces are compatible

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A Brief History of UNIX

• Late 1960s UNIX operating system developed
• 1970s
• Antitrust laws and ATT
• Anyone could purchase the source code
• New versions of UNIX appeared
• System V, BSD
• 1980s
• Rights changes hands, now owned by Novell
• Open Group owns UNIX trademark

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Varieties of UNIX

• Many varieties (flavors, distributions)
• Share several features
• UNIX operating system
• Divided into two main categories
• Proprietary
• Open source

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Proprietary UNIX

• Source code unavailable
• Available only by purchasing licensed copy from
  Novell
• Vendors
• Apple Computer Mac OS X Server
• Sun Microsystems Solaris
• IBM AIX

27
Open Source UNIX

• Customizable
• No licensing fees!!!
• Open source (freely distributable software)
• UNIX GNU
• BSD
• Linux

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Two Popular Flavors of UNIX

• Sun Solaris (proprietary)
• Runs on Suns SPARC-based servers
• All commercially supported operating system
  benefits
• Linux (open source)
• Developed by Linus Torvalds (1991)
• Highly stable
• Free!!!!

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Common Features of UNIX Linux

• Native TCP/IP networking
• Can be deployed as routers and/or firewalls
• DNS, DHCP services
• Operates over many different network topologies,
  physical media

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UNIX Linux File Systems

• No drive letters!
• Native file systems
• Solaris UFS (UNIX file system)
• Linux ext3 (third extended file system)