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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].
Layers of Computer systems (ch-2,2.1,OS Overview)
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 kernelCommunication.
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.
Thank You