Summary on DistributedSummary on DistributedSystem Concepts and ArchitecturesSystem Concepts and Architectures

Vijay NeelakandanVijay Neelakandan

vneelakandan1@student.gsu.eduvneelakandan1@student.gsu.edu

What is Distribution system?What is Distribution system?

A A distributed systemdistributed system is a collection of is a collection of autonomous computers linked by a autonomous computers linked by a computer network that appears to the user computer network that appears to the user as a single computer as a single computer

Why distributed system?Why distributed system?

Resource sharingResource sharing Specialized hardwareSpecialized hardware Data/DatabaseData/Database

Computation speedupComputation speedup Partitioning computations allowing concurrent Partitioning computations allowing concurrent

processingprocessing Load balancingLoad balancing

ReliabilityReliabilityIn event of system resource failure, shift its In event of system resource failure, shift its processing load to another similar resourceprocessing load to another similar resource

Distributed System Categories?Distributed System Categories?

Multiple computer systems collaborating to Multiple computer systems collaborating to deliver a single applicationdeliver a single application

Multiple applications collaborating together Multiple applications collaborating together as a systemas a system

Architecture depends on the category.Architecture depends on the category.

Disadvantages of Distributed Disadvantages of Distributed SystemsSystems

Difficulties of developing distributed Difficulties of developing distributed softwaresoftware

Networking ProblemsNetworking Problems

Security problems[B. Karp, S. Hailes]Security problems[B. Karp, S. Hailes]

GoalsGoals

Access TransparencyAccess Transparency

Local and remote resources are accessed using Local and remote resources are accessed using identical operationsidentical operations

Location TransparencyLocation Transparency

Users cannot tell where hardware and software Users cannot tell where hardware and software resources (files, CPU's) are located; the name of resources (files, CPU's) are located; the name of the resource shouldn't encode the location of the the resource shouldn't encode the location of the resource resource

Goals Contd..Goals Contd..

Migration(Mobility) TransparencyMigration(Mobility) TransparencyResources should be free to move from one Resources should be free to move from one location to another without having their names location to another without having their names changedchanged

Failure TransparencyFailure TransparencyApplications should be able to complete their Applications should be able to complete their task despite failures occurring in certain parts of task despite failures occurring in certain parts of the system the system

Goals contd..Goals contd..

Concurrency TransparencyConcurrency Transparency

The users will not notice the existence of other The users will not notice the existence of other users in the system(even if they access the users in the system(even if they access the same resources)same resources)

Performance TransparencyPerformance Transparency

Load variation should not lead to performance Load variation should not lead to performance degradation. This could be achieved by degradation. This could be achieved by automatic reconfiguration as response to automatic reconfiguration as response to changes of the loadchanges of the load

Goals Contd..Goals Contd..

Replication TransparencyReplication Transparency

The system is free to make additional copies of The system is free to make additional copies of files and other resources (for purpose of files and other resources (for purpose of performance and/or reliability), without the users performance and/or reliability), without the users noticing. Example: several copies of a file; at a noticing. Example: several copies of a file; at a certain request that copy is accessed which is certain request that copy is accessed which is closest to the clientclosest to the client

What is an Operating System???What is an Operating System???

A program acting as an intermediary between A program acting as an intermediary between the user and the hardware.the user and the hardware.

Purpose: To provide an environment, where Purpose: To provide an environment, where user can execute programs in a convenient and user can execute programs in a convenient and efficient manner.efficient manner.

The operating systems provides certain services The operating systems provides certain services to the users to make their tasks easier.to the users to make their tasks easier.

Operating System Design GoalsOperating System Design Goals

EfficiencyEfficiency

FlexibilityFlexibility

ConsistencyConsistency

RobustnessRobustness

Why Operating System Why Operating System Services?Services?

OS provides an environment for the executions OS provides an environment for the executions of the programs.of the programs.

Services are provided for the convenience of the Services are provided for the convenience of the programmer , to make the programming task programmer , to make the programming task easier.easier.

Services provided differ from one operating Services provided differ from one operating system to another operating system.system to another operating system.

Services provided by the operating Services provided by the operating system?system?

Program ExecutionProgram ExecutionI/O OperationsI/O OperationsFile-system manipulationFile-system manipulationCommunicationsCommunicationsError DetectionError DetectionResource AllocationResource AllocationAccountingAccountingProtectionProtection

Communication Network ProtocolCommunication Network Protocol

Application LayerApplication Layer

This layer provides application services for This layer provides application services for file transfers, , e-mail, and other , and other network software services. services. Telnet and and FTP are are applications that that

exist entirely in the application level. exist entirely in the application level.    

Transport LayerTransport Layer

This layer provides transparent transfer of data This layer provides transparent transfer of data between end systems, or between end systems, or hosts, and is , and is responsible for end-to-end error recovery and responsible for end-to-end error recovery and flow control. It ensures complete data transfer.flow control. It ensures complete data transfer.

Design Issues of Distributed Design Issues of Distributed SystemsSystems

OpennessOpennessSecuritySecurityReliability and fault toleranceReliability and fault toleranceScalabilityScalabilityConcurrencyConcurrencyAchieving Transparency[A. S. Tanenbaum]Achieving Transparency[A. S. Tanenbaum]

FlexibilityFlexibility

The flexible operating systems are taken to be The flexible operating systems are taken to be those whose designs have been motivated to those whose designs have been motivated to some degree by the desire to allow the system some degree by the desire to allow the system to be tailored, either statically or dynamically, to to be tailored, either statically or dynamically, to the requirements of specific applications or the requirements of specific applications or application domains. application domains.

ReliabilityReliability

In general, In general, reliabilityreliability (systemic def.) is the (systemic def.) is the ability of a person or system to perform and ability of a person or system to perform and maintain its functions in routine circumstances, maintain its functions in routine circumstances, as well as hostile or unexpected circumstances.as well as hostile or unexpected circumstances.

Reliability is generally considered important by Reliability is generally considered important by end users end users

Distributed Computing EnvironmentDistributed Computing Environment

The DCE is a software that supplies a framework and The DCE is a software that supplies a framework and toolkit for developing client/server applications. The toolkit for developing client/server applications. The framework includes a Remote Procedure Call (RPC) framework includes a Remote Procedure Call (RPC) mechanism, a naming (directory) service, a time service, mechanism, a naming (directory) service, a time service, an authentication service, an authorization service and a an authentication service, an authorization service and a Distributed File System.Distributed File System.

DCE runs on all major computing platforms and is DCE runs on all major computing platforms and is designed to support distributed applications in designed to support distributed applications in heterogeneous hardware and software environments. heterogeneous hardware and software environments. DCE is a key technology in three of today's most DCE is a key technology in three of today's most important areas of computing: security, the World Wide important areas of computing: security, the World Wide Web, and distributed objects. Web, and distributed objects.

DCEDCE

RESEARCHRESEARCH

Distributed Wireless Communication Distributed Wireless Communication SystemSystem

by by

Shidong Zhou   Ming Zhao   Xibin Xu   Shidong Zhou   Ming Zhao   Xibin Xu   Jing Wang   Yan Yao   Jing Wang   Yan Yao   Tsinghua Univ., Beijing, ChinaTsinghua Univ., Beijing, China

AbstractAbstract

The Distributed wireless communication system The Distributed wireless communication system is the new architecture for future public wireless is the new architecture for future public wireless access.access.

This can be done with the help of distributed This can be done with the help of distributed antennas, distributed processors, and distributed antennas, distributed processors, and distributed control.control.

Abstract contd..Abstract contd..

With distributed antennas, the system capacity With distributed antennas, the system capacity can be expanded through dense frequency can be expanded through dense frequency reuse, and the transmission power can be reuse, and the transmission power can be greatly decreased. greatly decreased.

With distributed processors control, the system With distributed processors control, the system capacity can be increased by co-processing of capacity can be increased by co-processing of signals to and from multiple antennas.signals to and from multiple antennas.

How Load Balancing Done?How Load Balancing Done?

By the simulation of the distributed time-driven By the simulation of the distributed time-driven algorithm, the efficiency of load balancing and algorithm, the efficiency of load balancing and the division method are proved to be acceptable.the division method are proved to be acceptable.

Load balancing can also be done by Distributed Load balancing can also be done by Distributed private network in DWCS.private network in DWCS.

ReferencesReferences

1)Distributed Wireless communication system1)Distributed Wireless communication system http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?

arnumber=1186553arnumber=1186553

2)How load balancing done?2)How load balancing done? http://cat.inist.fr/?aModele=afficheN&cpsidt=18184027http://cat.inist.fr/?aModele=afficheN&cpsidt=18184027

3)Distributed Cache for wireless communication 3)Distributed Cache for wireless communication systemsystem

http://www.freepatentsonline.com/6941338.htmlhttp://www.freepatentsonline.com/6941338.html

ReferencesReferences

4)Distributed Operating Systems & Algorithms, Randy 4)Distributed Operating Systems & Algorithms, Randy Chow and Theodore Johnson, Addison Wesley, 1997.Chow and Theodore Johnson, Addison Wesley, 1997.

5) Distributed Systems principles and paradigms by 5) Distributed Systems principles and paradigms by Andrew S. Tanenbaum, Maarten van Steen, 2002.Andrew S. Tanenbaum, Maarten van Steen, 2002.

6) 6) Ge, Z.; Figueiredo, D.R.; Sharad Jaiswal; Kurose, J.; Towsley, Ge, Z.; Figueiredo, D.R.; Sharad Jaiswal; Kurose, J.; Towsley, D.; D.; Modeling peer-peer file sharing systemsModeling peer-peer file sharing systems, INFOCOM 2003. , INFOCOM 2003. Twenty-Second Annual Joint Conference of the IEEE Twenty-Second Annual Joint Conference of the IEEE Computer and Communications Societies. IEEE Volume 3, Computer and Communications Societies. IEEE Volume 3, 30 March-3 April 2003 Page(s):2188 - 2198 vol.330 March-3 April 2003 Page(s):2188 - 2198 vol.3

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