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Summary on Distributed System Concepts and Architectures

Summary on Distributed System Concepts and Architectures. Vijay Neelakandan vneelakandan1@student.gsu.edu. What is Distribution system?. A distributed system is a collection of autonomous computers linked by a computer network that appears to the user as a single computer.

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Summary on Distributed System Concepts and Architectures

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  1. Summary on DistributedSystem Concepts and Architectures Vijay Neelakandan vneelakandan1@student.gsu.edu

  2. What is Distribution system? A distributed system is a collection of autonomous computers linked by a computer network that appears to the user as a single computer

  3. Why distributed system? • Resource sharing • Specialized hardware • Data/Database • Computation speedup • Partitioning computations allowing concurrent processing • Load balancing • Reliability • In event of system resource failure, shift its processing load to another similar resource

  4. Distributed System Categories? • Multiple computer systems collaborating to deliver a single application • Multiple applications collaborating together as a system • Architecture depends on the category.

  5. Disadvantages of Distributed Systems • Difficulties of developing distributed software • Networking Problems • Security problems[B. Karp, S. Hailes]

  6. Goals • Access Transparency Local and remote resources are accessed using identical operations • Location Transparency Users cannot tell where hardware and software resources (files, CPU's) are located; the name of the resource shouldn't encode the location of the resource

  7. Goals Contd.. • Migration(Mobility) Transparency Resources should be free to move from one location to another without having their names changed • Failure Transparency Applications should be able to complete their task despite failures occurring in certain parts of the system

  8. Goals contd.. • Concurrency Transparency The users will not notice the existence of other users in the system(even if they access the same resources) • Performance Transparency Load variation should not lead to performance degradation. This could be achieved by automatic reconfiguration as response to changes of the load

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

  10. What is an Operating System??? • A program acting as an intermediary between the user and the hardware. • Purpose: To provide an environment, where user can execute programs in a convenient and efficient manner. • The operating systems provides certain services to the users to make their tasks easier.

  11. Operating System Design Goals • Efficiency • Flexibility • Consistency • Robustness

  12. Why Operating System Services? • OS provides an environment for the executions of the programs. • Services are provided for the convenience of the programmer , to make the programming task easier. • Services provided differ from one operating system to another operating system.

  13. Services provided by the operating system? • Program Execution • I/O Operations • File-system manipulation • Communications • Error Detection • Resource Allocation • Accounting • Protection

  14. Communication Network Protocol

  15. Application Layer • This layer provides application services for file transfers, e-mail, and other networksoftware services. Telnet and FTP are applications that exist entirely in the application level.

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

  17. Design Issues of Distributed Systems • Openness • Security • Reliability and fault tolerance • Scalability • Concurrency • Achieving Transparency[A. S. Tanenbaum]

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

  19. Reliability • In general, reliability (systemic def.) is the ability of a person or system to perform and maintain its functions in routine circumstances, as well as hostile or unexpected circumstances. • Reliability is generally considered important by end users

  20. Distributed Computing Environment • The DCE is a software that supplies a framework and toolkit for developing client/server applications. The framework includes a Remote Procedure Call (RPC) mechanism, a naming (directory) service, a time service, an authentication service, an authorization service and a Distributed File System. • DCE runs on all major computing platforms and is designed to support distributed applications in heterogeneous hardware and software environments. DCE is a key technology in three of today's most important areas of computing: security, the World Wide Web, and distributed objects.

  21. DCE

  22. RESEARCH

  23. Distributed Wireless Communication System by Shidong Zhou   Ming Zhao   Xibin Xu   Jing Wang   Yan Yao   Tsinghua Univ., Beijing, China

  24. Abstract • The Distributed wireless communication system is the new architecture for future public wireless access. • This can be done with the help of distributed antennas, distributed processors, and distributed control.

  25. Abstract contd.. • With distributed antennas, the system capacity can be expanded through dense frequency reuse, and the transmission power can be greatly decreased. • With distributed processors control, the system capacity can be increased by co-processing of signals to and from multiple antennas.

  26. How Load Balancing Done? • By the simulation of the distributed time-driven algorithm, the efficiency of load balancing and the division method are proved to be acceptable. • Load balancing can also be done by Distributed private network in DWCS.

  27. References 1)Distributed Wireless communication system http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1186553 2)How load balancing done? http://cat.inist.fr/?aModele=afficheN&cpsidt=18184027 3)Distributed Cache for wireless communication system http://www.freepatentsonline.com/6941338.html

  28. References 4)Distributed Operating Systems & Algorithms, Randy Chow and Theodore Johnson, Addison Wesley, 1997. 5) Distributed Systems principles and paradigms by Andrew S. Tanenbaum, Maarten van Steen, 2002. 6) Ge, Z.; Figueiredo, D.R.; Sharad Jaiswal; Kurose, J.; Towsley, D.; Modeling peer-peer file sharing systems, INFOCOM 2003. Twenty-Second Annual Joint Conference of the IEEE Computer and Communications Societies. IEEE Volume 3, 30 March-3 April 2003 Page(s):2188 - 2198 vol.3

  29. THANK YOU

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