Operating Systems on the Network Approaches to managing network resources –Peer-to-peer model All...
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Transcript of Operating Systems on the Network Approaches to managing network resources –Peer-to-peer model All...
Operating Systems on the Network
• Approaches to managing network resources– Peer-to-peer model
• All the computers on the LAN have the same authority and each can act as a server to the other computers
– Client/server model• One or more computers control the resources for all
computers on the network• These servers require a network operating system (NOS)• Also called the domain model
Example of a Peer-to-Peer Network
Example of a Network Operating System (NOS)
Operating Systems for the Client
• On a LAN, each PC must have an operating system that is capable of interfacing with a network interface card and the resources available on the network
• Options for a personal computer OS– Windows 9x (most popular)– Windows NT
• Windows NT Workstation• Windows NT Server
– Linux
Windows 9x
• Low-level; primarily used for personal computers• Backward compatible with DOS,
Windows 3.x, and legacy hardware devices• Supports network access• Can be used in a peer-to-peer or client/server
network
Windows 9x
Windows 9x
Windows NT Workstation
• Works well as a stand-alone OS or as an OS on a PC that is part of a peer-to-peer network or client/server network
• Like Windows 2000, does not support legacy software or hardware; expects hardware and software to follow the rules of relating to a true 32-bit OS
The Windows NT Desktop
Linux
• A scaled-down version of UNIX• Small enough to run on a 486 computer, but has
network capabilities similar to a full-fledged commercial version of UNIX
• Appropriate for – A small company environment with low-volume traffic
for internet services– Internet-in-a-box devices– A web server or proxy server for a LAN
Largest Drawbacks to Using Linux
• Lack of support and standards
• Lack of application software written for it
• Lack of experienced technical people
An Operating System
The Shell and the Kernel
• Operating system kernel– Core portion of the OS that loads applications
and manages files, memory, and other resources
• Operating system shell– Responsible for providing an interface for
users to enter OS commands
Different Approaches to a Shell
• Windows– Uses a GUI shell as the default shell
• Linux and UNIX– Use a command-line shell as the default shell,
and a GUI as an add-on feature
A Windows Shell
A Linux Shell
Network Operating Systems
• Reside on the controlling computer in the network
• Control software, data, and devices a user can access
Criteria to Consider When Selecting a NOC
• Reliability• Performance• Adaptability• Ease of use and ease of installation• Affordability• Security• Scalability
Popular Network Operating Systems
• Windows NT Server and Windows NT Enterprise Server
• Windows 2000
• Netware by Novell
• UNIX and Linux
Windows NT Server and Windows NT Enterprise Server
• Designed to create and support a client/server network for a LAN called a domain
• One computer is designated the primary domain controller (PDC)– Server that controls a database of user accounts,
group accounts, and computer accounts– Database is also called a directory database or
security accounts manager (SAM) database
• Backup domain controller (BDC)– A server that contains a read-only copy of the domain
database
A Windows NT Domain
Windows 2000
• Includes four operating systems– Windows 2000 Professional– Windows 2000 Server– Windows 2000 Advanced Server– Windows 2000 Datacenter Server
Netware by Novell
• A popular NOS that can provide fast file and database access
• Uses a suite of protocols called IPX/SPX, which generally correspond to the TCP/IP protocols
UNIX
• Provides services over the Internet; can also support a LAN as a file and database server
• Used by 48% of today’s web servers on the Internet
• The accepted mainstay for the firewall market• TCP/IP and Java were developed in a UNIX
environment• Several hardware manufacturers offer their own
version of UNIX
Advantages and Disadvantages of UNIX
• Advantages – Highly reliable– Highly scalable– High performing– Powerful
• Disadvantages– Not easy to learn– Requires experienced, well-trained administrative and
technical staff
Linux
• Originally an OS for a personal computer; fast becoming a viable option as a NOS
• Performs at about 40% of the speed of Windows NT Server
Network Services
• Wide range of possible network services
• Two primary services are printers and directory shares
• Others services include:– Groupware applications– Mail packages– Shared whiteboard applications– Web servers
Installing, Removing, and Configuring Network Services
• Driver or network itself provides network service • Most NOSs have administrative tool for installing
and removing network services• Control network services in two ways:
– Through global services administrative tool– Through console plug-in related to specific
service– Add new tools under the Microsoft
Management Console (MMC)
Network Bindings
• Process of linking network components from various levels of network architecture to ensure communication between them– Associates upper-layer services and protocols
to lower-layer network adapter drivers
• Bind the most frequently used protocol, service, or adapter first to speed network connections
Network Printing
• Redirector intercepts printer requests and forwards them to print servers or network-connected printers
• Network printing involves installing printer– Some clients require local printer drivers– Others access printer drivers from print server
• New local printer points to print share
Printer Management
• Manage printers from local direct access or through network printer share; – Windows 2000/2003/XP lets you manage
printers through Web browser• Printer management includes:
– Granting and restricting user access to printers– Monitoring print queue– Limiting access by time frame, department, or
priority– Updating local and remote printer drivers– Maintaining printers; managing printers
remotely
Sharing Fax Modems
• Feature not usually default component in NOS– Use third-party add-on product
• Once drivers are installed, manage and administer fax shares like printer shares
Network Directory Shares
• Let clients access and interact with storage devices on network
• Three ways to access shared directory:– Map unused local drive letter to directory share– Use UNC name to reference directory share– Select directory share from list of available shares
• Manage directory share by granting or restricting user access levels
• Linux uses either NFS or Samba to share files; NFS is the native Linux/Unix file sharing service whereas Samba is compatible with Windows systems
Network Applications
• Designed for multiple simultaneous users on numerous computers on network
• Three essential types of network application tools:– E-mail or messaging– Scheduling or calendaring– Groupware
• Easier to administer• Poor network performance or limited
bandwidth degrades application performance
Network Applications (continued)
• If network is down, application is unusable
• Three types of architecture for network applications:– Centralized – applications operate only on
server– File-system sharing – application on client, but
share database or storage directory– True client/server – some resides on server and
some on client; group activities processed on server
E-Mail or Messaging
• Distributes messages across network or Internet– Internet mail standards include SMTP, POP3,
and/or IMAP– See Simulation 8-1 for a visual explanation of
how e-mail operates
• Includes many sophisticated abilities, such as attaching files, filtering, using distribution lists, and address book
E-Mail or Messaging (continued)
• Numerous e-mail protocols, including:– X.400 – hardware- and software-independent
message-handling protocol– Internet Message Access Protocol (IMAP) –
includes advanced message controls and fault tolerance
– Message Handling System (MHS) – Novell standard similar to X.400
E-Mail or Messaging (continued)
• Numerous e-mail protocols, including:– Post Office Protocol, version 3 (POP3) –
used by e-mail clients to download incoming messages
– Simple Mail Transfer Protocol (SMTP) – current standard for Internet e-mail
– X.500 – similar to X.400, but offers improved directory services
Scheduling or Calendaring
• Provides easy coordination of meetings and appointments
• Most offer private and public calendars, appointment books, task lists, and contact address books
• May offer reminders of special events• Often integrated into e-mail programs• May print daily, weekly, monthly, and yearly
schedules
Groupware
• Lets multiple users interact simultaneously with single file, document, or project
• Most popular multiuser multimedia authoring tools include Lotus Notes, Novell’s GroupWise, and DEC’s TeamLinks
• Able to synchronize users and coordinate distributed data and activities
• PDA integration into groupware is exploding so that users can take their calendars and e-mail with them on a handheld