Network Operating Systems

It controls the real resources of the server machines as well as the communications over the media and the client component of network workstations.

Multitasking

The ability to support multiple processes at one time.
Required for an effective NOS.

Two types of multitasking.

Preemptive (NT)
Cooperative (WIN3.X)

NOS Functionality
Manages the server, the client, and the media.

Logically connects all network devices.
Controls resource access.
Coordinates communications.
Supports security and privacy.
Coordinates and controls device functionality

NOS Location

Components reside on both client and server computers and include the protocols that keep order on the media.
Sometimes, network workstations can provide both client and server functionality.

Client Network Software

Redirector (AKA requestor)
Routes resource requests to appropriate device.
Operates at the presentation layer.
Operates transparently.
Shields user from complexity.

Designator

Keeps track of the drive letters assigned locally (mapped) to remote shared drives.

Universal Naming Convention (UNC)

A standard naming method for network resources.
Provides an alternative to drive mapping.
Usually takes the form of:
\\servername\sharename

Server Network Software

NOS component that provides resources.
Features include:
User and group management
User authentication at logon
Management, control, and auditing tools
Fault tolerance

NOS Installation

Similar to OS installation.
Requires preparation that identifies:
• Architecture and Topology
• Network scope and size
• Server partition and file system
• Name and naming convention
• Client O/Ss
• Server specific functionality

NOS Installation Detail

Network Adapter Configuration
Number of adapters, IRQs...
Protocol selection
Routable or Nonroutable
Where relevant, TCP/IP parameters.
IP Address, Subnet Mask, default gateway, WINs and DNS.

Hard disk organization (partitioning and file system)
Dual or single boot configuration

Network Services

Basic resources found in all networks.
Printer services
Directory shares
Other services as desired

Network Bindings

Establish a logical link between the upper protocols and lower protocols on the NIC.
On the client side, the order of the bindings can impact network performance.
Most frequently used protocol, service, or adapter should be bound first.

Network Applications

Designed for multiple simultaneous users on numerous connected computers.

Three Net Applications Architectures

Centralized
File system sharing
True client/server (Utilizes processing power of both client and server)

Most popular network application is email.

E-mail
Based on a common protocol and standard of communication.

E-mail protocols include:

X.400 hardware and software independent
X.500
SMTP
MHS

X.400

Hardware and software independent

Similar to X.400 with improved directory services. (global address database)

Current standard for Internet based mail