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Unformatted text preview: er, and advancements in
communication technology have resulted in the availability of cost-effective and
highly efficient computer networks. The net result of the advancements in these
two technologies is that the price-performance ratio has now changed to favor the
use of interconnected multiple computers in place of a single, high-speed
computer. Computer systems consisting of interconnected, multiple computers are
called distributed computing systems. That is, a distributed computing system is a
collection of computer systems interconnected by a communication network in
which each computer has its own local memory and other peripheral devices, and
the communication between any two computers of the system takes place by
passing messages over the communication network.
The operating systems commonly used for distributed computing systems can be
broadly classified into two types - network operating systems and distributed
operating systems. The three most important features commonly used to
differentiate between these two types of operating systems are system image,
autonomy, and fault tolerance capability. These features are explained below.
1. System Image. The most important feature used to differentiate between the
two types of operating systems is the image of the distributed computing system
from the point of view of its users. In case of a network operating system, the
users view the distributed computing system as a collection of distinct machines
connected by a communication subsystem. That is, the users are aware of the fact
that multiple computers are being usecf. On the other hand, a distributed
operating system hides the existence of multiple computers and provides a singlesystem image to its users. That is, it makes a collection of networked machines
appear to its users as a virtual uniprocessor by providing similar type of user
interface as provided by centralized operating systems.
2. Autonomy. In a network operating system, each computer of the distributed
computing system has its own local ope...
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This document was uploaded on 04/07/2014.
- Spring '14