Distributed Computing Environment.pptx

8/18/2019 Distributed Computing Environment.pptx

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Distributed Computing Environme


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Outline• What is DCE?

• Why DCE ?

• Where it used ?

• Goals of DCE.

•

DCE architecture.• Advantage of DCE.

• Disadvantage of DCE.

• Conclusion.


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What is DCE:

DCE (Distributed Computing Environment) is an instandard softare technology for managing comand data e!change in a distributed systems.


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" #ot an $% or an Application

" An &ntegrated %et $f %ervices And 'ools 'hat can be insta

a coherent environment on the top of e!isting $%.

" %erve as a platform for building running distributedapplications

What is DCE (cont.)


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What is DCE (cont.)

• Distributed Application

• DCE

• $% and netor %ervices

" Conceals di*erences beteen machines provides tran


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What is DCE (cont.)DCE is based on three distributed computing mod

"Client/server + A ay of organi,ing a distributedapplication.

"Remote procedure call + A ay of communicatingbeteen parts of a distributed application.

"Shared fles +A ay of handling data in a distributedsystem.


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Why DCE?

DCE addresses + -ile consistency cloc synchroni,atiosecurity by providing an integrated set of crossplatform/services hich aids in the development of distriapplications.


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Where it used:

&t use client/server model

DCE is typically used in a larger netorof computing systems.


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Goals of DCE:

0) can run on many di*erent computers operatingsystems (1ni! 23% indos) and netors in adistributed system.

4) 5rovide a mechanism for synchroni,ing clocson di*erent machines.


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Goals of DCE (cont.):

6) 5rovide tools to mae it easier to ritedistributed applications in hich multiple users atmultiple locations can or together.

7)5rovide e!tensive tools for authentication andaccess protection .


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DCE architecture:

DCE cell.DCE threadsDCE remote procedure callDCE directory service+ cell directory service

DCE distributed time serviceDCE security serviceDistributed 8le service


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DCE cell:

A cell is a group of users systems and resources that arepart of group and having there on directory service andsecurity service .


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DCE cell: "1sers log into accounts in a cell.

"Access control lists (AC9s) identify users and groups inthe cell (they can also refer to users and groups inother cells).


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DCE cell:

"A DCE cell can be con8gured in many aysdepending on its users: re;uirements.

"A cell consists of three inds of nodes+

"DCE user machines. "DCE administrator machines. "DCE server machines.


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DCE cell:-DCE user machines are general"purpose DCEmachines. 'hey contain softare that enables them toact as clients to all of the DCE services.

-DCE administrator machines contain softare that

enables a DCE administrator to manage DCE systemservices remotely.

"The DCE server machines are e;uipped ithspecial softare enabling them to provide one or moreof the DCE services.


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DCE cell:

-Every cell must have at least one each o the oservers in order to unction:

" Cell Directory Server: responsible for repository of r

and AC9." Security Server + responsible for authentication." Distributed Time Server : that provides an accurate proper functioning of the entire cell


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DCE cell:


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DCE thread :

"DCE thread pacage+ a collection of user"level library prothat allo processes to create delete and manipulate th "multiple tass could occur at the same time to com

process(or).

"a single threaded program can be converted into multitone by setting parameter indicating that more threadsused.


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DCE thread :

-All threads in a process share the same address space 8system and other process resources. Each thread has its program counter stac and registers

"7 %tates+ < =unning =eady Waiting 'erminated


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cheduling:"Determines ho long a thread may run and hich threadrun ne!t.

"%imilar to scheduling processes.

" 'hreads in DCE have priorities.

- DCE has to scheduling algorithms: " -&-$ " =ound =obin


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cheduling algorithms:-!"!#search and locate the priority ;ueue ith one or more thrfrom highest to loest run the 8rst thread on this ;ueue 8nish by blocing or e!iting.

- Round Robinis generally used time is assigned to each process in e;uportions and in circular order handling all processesithout priority. =ound"robin scheduling is simple easy to implement.


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DCE remote procedure call"=5C

"DCE is based on the client/server model. =5C pacage ofallos a client process to call a procedure on a remote co&t allos application programmer to e!tend the local proc

call to a distributed environment.


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DCE remote procedure call

• =5C hides communication detail and removes system ahardare dependencies. &t can automatically handle daconversions beteen the client and the server ithout c

hether they run on the same or di*erent architecture same or di*erent byte ordering.


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DCE remote procedure call


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!dvantage of using "#C

" $perating %ystem &ndependence.

"3achine &ndependence.

"9anguage &ndependence.

"5rotocol &ndependence


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DCE directory service:

• 5rovide up"to"date addressing information.

• &ts distributed service.

• A replicated service.


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DCE $ime ervices:

• &t enables distributed applications on di*erent computerdetermine event se;uencing duration and scheduling.

• @eeps clocs on separate computers participating in a d

system synchroni,ation.

• &t uses coordinated universal time(1'C) to synchroni,e Dtime.


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DCE $ime ervices:

• D'% synchroni,es the clocs in netored computer syschecs time synchroni,ation and adusts clocs hen therror e!ceeds a certain acceptable range.


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DCE ecurity ervice:"DCE %ecurity %ervice comprises several parts+

• authentication service%

'his service enables to processes on di*erent machinecertain of one another:s identity or authenticated.

• audit service%

to trac the services accessed by the user and build a rcase of security breach.


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DCE ecurity ervice:

• privilege service%

to determine if the user has authori,ation to access the services.

• registry service%

'he registry service is a replicated service that managessecurity database. 'he security database contains entriesecurity entities hich are called principals.


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DCE ecurity ervice:


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DCE distrbuted file ervice:

• 'he DCE Distributed !ile System (DCE/D-%) is the reaccess protocol used ith the DCE.

• Allos users to access and share 8les stored on a 8le se

anyhere on the netor ithout noing the physicaof the 8le.


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D!S Data #rgani(ation:

• -iles and directories.

•

-ile sets.• Aggregates.


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D% Components

• Cache 3anager

• -ile E!porter

• 'oen 3anager

• DCE 9ocal -ile %ystem

• -ileset %erver

• =eplication %erver

• 1pdate %erver

• -ileset 9ocation %erver

• Bacup %erver


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D% Components


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!dvantage of DCE :

• 0) 'he services provided by DCE is much easier to use tones found in other computer netoring environments

• 4) the DCE security service provides a reliable ay to dea user in a distributed system should be alloed to perfcertain action


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Disadvantage of DCE :

• With all these advantages DCE has no faded from theC$=BA and DC$3 have become dominant in the DistribComputing Environment .'his is due to the fact that DCsupport $bect oriented languages.


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Conclusion• 'hough DCE as the de facto standard for middleare a

tions its lac of support for obect"oriented languages hthe greatest cause for DCE to lose maret share. ence oncepromising technology is no used only for 9egacy syste

support. 3any ne Distributed"computing ventures are using C$=BA or DC$3. ence e can safely say DCE very good start to Distributed Computing.


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'han ou

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Distributed Computing Environment.pptx