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Distributed System Services. Prepared By:- Monika Patel. mpatel56@student.gsu.edu. Overview. What is operating system? Layers of O.S. Basic Services provided by O.S. Fundamental Services. Primitive Services. Services by System Servers. Value Added Services.
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Distributed System Services Prepared By:- Monika Patel. mpatel56@student.gsu.edu
Overview • What is operating system? • Layers of O.S. • Basic Services provided by O.S. • Fundamental Services. • Primitive Services. • Services by System Servers. • Value Added Services.
What is an operating system? (ch-10,OS,Nell dale, john lewis) An operating system • Is a service provider. • Manages computer resources, such as memory and input/output devices.[1] • Provides an interface through which a human can interact with the computer.[1]
Continued • Allows an application program to interact with other system resources[1].
Basic Services Provided By O.S (Ch-3,3.12,OS structure, Silberschatz ,Galvin,Gange) • Program development • Editors and debuggers. • Access to I/O devices. • Controlled access to files • System access • Program execution
Continued (Ch-3,3.12,OS structure, Silberschatz ,Galvin,Gange) • Error detection and response • Internal and external hardware errors • Memory error. • Device failure. • Software errors • Arithmetic overflow.
Continued (Ch-3,3.12,OS structure, Silberschatz ,Galvin,Gange) • Accounting • Collect usage statistics. • Monitor performance. • Used to anticipate future enhancements. • Used for billing purposes.
Fundamental Services (ch-2,2.3,Distributed OS& Algorithms,Randy chow,Theodore johnson.) • Three fundamental services are there . • System Primitives. • Services By system servers. • Value Added Services.
What is kernel? (ch-2,2.1,OS Overview) • Portion of operating system that is • always in main memory • Contains most-frequently used functions • Also called the nucleus • Good performance of the kernel is very important
Fundamental function of kernel • Communication. • Synchronization. • Processor multiplexing.
Primitive Services (ch-2,2.3,Distributed OS& Algorithms,Randy chow,Theodore johnson.) • Primitive services are those that must be implemented on kernel of each node in the system. • In Distributed system when communicationis done through message passing set of primitives for send and receive must be defined and implemented.
Continued • Synchronous Communication Send And receive primitives can be synchronous or asynchronous. • Synchronization Servers
What is Process Server? • It manages • creation, • deletion and • tracking of processes by allocating the resources like memory,processing time etc.
Services by System Servers ch-2,2.3,Distributed OS& Algorithms,Randy chow,Theodore johnson.) • What is System Services? The services which can be implemented anywhere in the system and performs the functions which is basic to the operation of a distributed system.
Continued • What is System Server? The service provider of the system is called system server.
Continued • To achieve transparency in Distributed System System server mappes physical objects with logical system names. • Name server Used to locate users ,processes and machines.
Continued • Directory Server It is used in conjuction with files and communication ports. • Network server Name server translation, selection of paths ,actual routing of information is done by network server.
Continued • Time Server It is used for synchronizing and scheduling of hardware and software activities. • Physical Clocks. • Logical Clocks.
Servers involved in managing shared system resources. • File servers. • Print servers. • Authentication server. In Short System Server provide services for managing processes,files and process communication.
Value Added Services ch-2,2.3,Distributed OS& Algorithms,Randy chow,Theodore johnson.) • Services that are not needed in the implementation of a Distributed System But useful in supporting Distributed Application. • Used To increase the computational performace and enhacement of fault tolerance or by need for cooperative activities.
Continued • Group Server It manages the creation and termination of group activities. Responsible for Group addressing ,communication ,contain information about membership, member privileges and admission policies..
Continued. • Web server is also the good example of a value added server.
Refrences:- [1]Computer science illuminated ,second edition,By Nell dale,John lewis. [2]Distributed operating systems & Algorithms,By Randy chow,Theodore johnson. [3]Operating System Overview ,Chapter 2.
Continued [4]Two-Hour Introduction to Operating Systems By Dr. Mads Haahr,Trinity College, Dublin. [5]Operating System concept by Silberschatz ,Galvin,Gange,ch -3 operating System structure.