2. WHAT IS DISTRIBUTED COMPUTING?
• A distributed computing system is basically a collection of
processors interconnected by a communication network in
which each processor has its own local memory and other
peripherals, and the communication between any two
processors of the system takes place by message passing over
the communication network.
• Distributed computing utilizes a network of many computers,
each accomplishing a portion of an overall task, to achieve a
computational result much more quickly than with a single
computer.
3. • In the term distributed computing, the word distributed
means spread out across space. Thus, distributed computing is
an activity performed on a spatially distributed system.
• A distributed system can consist of any number of possible
configurations, such as mainframes, personal computers,
workstations, minicomputers, and so on.
• These networked computers may be in the same room, same
campus, same country, or in different continents.
4. Agent Agent
Cooperation
Agent Cooperation
Distribution Distribution Cooperation
Distribution
Agent
Internet
Subscription Distribution
Job Request
Resource Large-scale
Management Application
5. BENEFITS OVER CENTRALIZED SYSTEM
Scalability:
The system can easily be expanded by adding more machines as
needed.
Redundancy:
Several machines can provide the same services, so if one is
unavailable, work does not stop. Additionally, because many
smaller machines can be used, this redundancy does not need to
be prohibitively expensive.
7. ARCHITECTURE
Various hardware and software architectures are used for
distributed computing.
Categories of architecture are as follows:
Client-Server: Client request to the server for dat , then
server send response to the user.
3-tier architecture: Three tier systems move the client
intelligence to a middle tier so that stateless clients can be
used.
Peer–to-peer: An architecture where there is no special
machines that provide a service or manage the resources.
Peers can serve both as clients and servers.
10. ADVANTAGE
Economics:
Computers harnessed together give a better price/performance
ratio than mainframes.
Speed:
A distributed system may have more total computing power than
a mainframe.
Inherent distribution of application:
Some applications are inherently distributed. E.g., an ATM-
banking application.
11. ADVANTAGE
Reliability:
If one machine crashes, the system as a whole can still survive if
you have multiple server machines and multiple storage devices
(redundancy).
Extensibility and Incremental growth:
Possible to gradually scale up (in terms of processing power and
functionality) by adding more sources (both hardware and
software). This can be done without disruption to the rest of the
system.
12. Disadvantages
Complexity:
Lack of experience in designing, and implementing a distributed
system. E.g. which platform (hardware and OS) to use, which
language to use etc.
Network Problem:
If the network underlying a distributed system saturates or goes
down, then the distributed system will be effectively disabled
thus negating most of the advantages of the distributed system.
Security:
Security is a major hazard since easy access to data means easy
access to secret data as well.
13. CONCLUSION
• The concept of distributed computing is the most efficient way
to achieve the optimization.
• Distributed computing is anywhere : intranet, Internet or
mobile ubiquitous computing (laptop)
• It deals with hardware and software systems, that contain more
than one processing / storage and run in concurrently.
• Main motivation factor is resource sharing; such as files ,
printers, web pages or database records.