This document defines and discusses the characteristics of distributed systems. It notes that a distributed system involves multiple connected CPUs working together as a single coherent system. The key characteristics of distributed systems include resource sharing, openness, concurrency, scalability, fault tolerance, and transparency. Examples of distributed systems include the worldwide web, computer clusters, and networked manufacturing systems.

1. Distributed System & its
Characteristics

2. Content
 Definition
 Characteristics
 Real lifeexamples
 Advantages
 Disadvantages

3. Definition
 A distributedsystem is:
• multipleconnectedCPUsworkingtogether.
• acollectionsofindependentcomputersthat
appearstoitsusersasasinglecoherentsystem.
 Examples: parallelmachines,networkedmachines

4. Characteristics
 Resource sharing
 Openness
 Concurrency
 Scalability
 FaultTolerance
 Transparency

5.  Resource Sharing
• Resource :
hardware - disks and printers
software - files, windows, and data objects
• Hardware sharing for :
convenience
reduction of cost
• Datasharingfor :
consistency - compilers and libraries
exchange of information- database
cooperative work - groupware

6.  Openness
The openness of a computer system is the
characteristics that determines whether the system
can be extended and re-implemented in various
ways.

7.  Concurrency
Multi-programming
Multi-processing
Parallel executions indistributed systems
–Manyusersusingthesameresources, application
interactions
–Manyservers respondingtoclientrequests

8.  Scalability
A system is described as scalable if remains effective
when there significant increase in the number of
resourcesandthenumbersofusers.

9.  Fault Tolerance
Computersfailthereforewe need:
– hardwareredundancy
– failuredetection
– recovery

10.  Transparency
System is perceived as a whole rather than a collection of
independentcomputers.

11. Examples
 Theworldwideweb–information,resource
sharing
 Clusters,Networkofworkstations
 Distributedmanufacturingsystem(e.g.automated
assemblyline)
 Networkembeddedsystem

12. Advantages
 Economics
 Speed
 Inherentdistribution
 Reliability
 Incrementalgrowth

13. Disadvantages
 Software
 Network
 Morecomponentsfail
 Security

14. More References
 http://www.csc.villanova.edu/~schragge/CSC8
530/Intro.html
 http://www.cis.upenn.edu/~lee/07cis505/Lec/l
ec-ch1-DistSys-v4.pdf