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Given by Mark Baker Portsmouth at Seamless Computing Birds of Feather SC97 on 18 Nov 97. Foils prepared 24 Nov 97
Outside Index
Summary of Material
| Emerging Applications |
| The Problem |
| Seamless Computing |
CORBA
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| CORBA and Seamless Computing |
| Seamless Computing Services |
| Conclusion |
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A Scalable Framework for Seamless Computing
Overview
Emerging Applications
The Problem...
Meta vs Seamless Computing
A Seamless Computing Framework
Seamless Computing Framework
CORBA
CORBA
Interface Definition Language (IDL)
CORBA Objects
The Object Request Broker (ORB)
The Object Request Broker (ORB)
CORBA
CORBA and Seamless Computing
Seamless Computing Services
Conclusion
Outside Index
Summary of Material
HTML version of Basic Foils prepared 24 Nov 97 
Full HTML Index
| Mark Baker |
| School of Computer Science |
| University of Portsmouth |
| Tel: +44 (1703) 844285 |
| Fax: +44 (1703) 844006 |
| Email: mab@sis.port.ac.uk |
| URL: http:/www.sis.port.ac.uk/~mab/ |
HTML version of Basic Foils prepared 24 Nov 97
Full HTML Index
| Emerging Applications |
| The Problem |
| Seamless Computing |
CORBA
|
| CORBA and Seamless Computing |
| Seamless Computing Services |
| Conclusion |
HTML version of Basic Foils prepared 24 Nov 97
Full HTML Index
| It is becoming increasing evident that emerging applications require the ability to exploit diverse, geographically distributed resources. |
| The reasons for this, may be for example, the location of specialised computational resources, availability of high-performance databases, high-speed network inter-connect, archival storage devices, etc... |
HTML version of Basic Foils prepared 24 Nov 97
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| How do we integrate resources of widely varying capabilities, connected by potentially unreliable networks and often located in different administrative domains ? |
| This problem is being tackled by a number of groups who are attempting to create either meta or seamless computing environments. |
HTML version of Basic Foils prepared 24 Nov 97
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| Metacomputing and Seamless computing have the same basic goals - that of integrating a distributed and heterogeneous system into one integrated computing environment. |
| Both need to deal with factors such as; resource management and scheduling, filesharing, security, interoperability and scalability. |
HTML version of Basic Foils prepared 24 Nov 97
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| The factors mentioned in the previous slide can be treated separately or taken together and by a process of abstraction generalised to provide a generic seamless computing framework. |
| This extensible framework can then be used to define the interfaces and interoperability layers between the disparate services available within our Seamless environment. |
HTML version of Basic Foils prepared 24 Nov 97
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| An obvious reference framework is the Common Object Request Broker Architecture (CORBA) being defined by the Object Management Group (OMG). |
| The OMG is a consortium that consists of over 700 companies that spans the whole spectrum of the computing industry - with the noticeable exception of Microsoft. |
HTML version of Basic Foils prepared 24 Nov 97
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| CORBA defines middleware that has the potential to replace all other existing forms of client/server middleware. |
| CORBA basically defines a framework that enables all applications to be unified via the object bus. |
| In addition CORBA separates the specification of a service from the actual implementation - this basically enables existing systems integrated within the bus. |
HTML version of Basic Foils prepared 24 Nov 97
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| CORBA allows intelligent components to discover each other and inter-operate via the bus. |
| CORBA also specifies an extensive set of bus related services - creating, deleting, relationships, etc... |
| One of the most import parts of CORBA is the Interface Definition Language (IDL). |
HTML version of Basic Foils prepared 24 Nov 97
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| The interface between components rather than actual code is specified. |
| These specifications are written in a neutral IDL that defines a components boundaries - basically its interface to potential clients. |
| Components written to IDL should be portable across languages, tools, OSs and networks. |
HTML version of Basic Foils prepared 24 Nov 97
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| A CORBA object is a element of intelligence that can live anywhere on the bus. |
| Remote clients can access their services via remote invocations. |
| All the clients need to know about an object to access its services is the interface that it publishes. |
HTML version of Basic Foils prepared 24 Nov 97
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| The ORB is the object bus. |
| Basically it lets objects make requests - and receive responses from - other objects located locally or remotely. |
| Client objects need not be aware of the mechanism for communicating with remote server objects. |
HTML version of Basic Foils prepared 24 Nov 97
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| An ORB can exist "just" locally or it can be inter-connected with other ORBs. |
| The connection of ORBs together over the Internet is via the usage of the Internet Inter-ORB Protocol (IIOP). |
HTML version of Basic Foils prepared 24 Nov 97 
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HTML version of Basic Foils prepared 24 Nov 97
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| IIOP to inter-connect Seamless environment. |
| Services provided by the computers in the Seamless environment are defined as Objects - IDL used to specify interfaces to these services. |
Service Objects can have:
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HTML version of Basic Foils prepared 24 Nov 97
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| Examples: |
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HTML version of Basic Foils prepared 24 Nov 97
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| CORBA can be used to define a Seamless Computing Framework. |
Advances
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