Presented By:- Sudipta Dhara Roll

Table of Content Table of Content 1.Introduction 2.How it evolved 3.Need of Middleware 4.Middleware Basic 5.Categories of Middleware 6.CORBA 7.Components of CORBA 8.Middleware tools 9.Conclusion 10.References 2

Introduction Introduction Middleware is computer software that connects distributed software components or applications. The distributed software consist of a set of services that allows multiple processes running on multiple machines to interact across a network. Middleware sits “in the middle” between application software working on different Operating Systems. 3

How it evolved How it evolved  Till 1980 most computing was based on central host computers. The term middleware first appeared in the late 1980s to describe network connection management software.  RPC was first developed circa 1982 by Birrell and Nelson. Early RPC systems that achieved wide use include those by Sun.  Then The OMG was formed in 1989, In the late 1990s HTTP became a major building block for various kinds of middleware. 4

Need of Middleware Need of Middleware 1.Middleware reduces application development and maintenance efforts. 2.Middleware provides distributed computing. 3.Distributed application without middleware are impractical. 5

Middleware Basics Middleware services are sets of distributed software that provide a more functional set of APIs than does the operating system and network services.This increased functionality allows an application to:  Locate transparently across the network, providing interaction with another application or service.  Be independent from network services.  Be reliable and available.  Scale up in capacity without losing functionality. 6

Categories of Middleware There are different kinds of middleware These are- 1.Transaction Processing(TP) Monitor Technology. 2.Message Oriented Middleware(MOM). 3.Remote Procedure Call(RPC). 4.CORBA. 5.Homegrown middleware solutions. 7

Common Object Request Broker Architecture (CORBA)  Driven by Microsoft and OMG.  It’s a standard architecture for distributed object systems.  It allows distributed, heterogeneous collection of object to interoperate.  The concepts are defined in such a way that they can be mapped to a number of programming languages.  It does not include language constructs to store variables or to express algorithms. 8

CORBA (Contd…) CORBA (Contd…)  IDL is designed to be independent of a particular programming language, though its syntax is oriented towards C++.  CORBA defines bindings to: C, C++, Smalltalk, Ada, Java and Cobol. These programming language binding determines how object type operations are implemented in server object and how client can make object request. 9

Component of CORBA  Client Stubs create and issue requests on the client side.  Dynamic invocation is done by Dynamic Invocation Interface, Here control is recursively given back to the client object until it polls for operation result.  ORB Interface Interact between Object Request Broker(ORB Core), Client and Server Objects at run time.  ORB activate the object using Object Adapter.  Implementation Skeletons receive and forward requests to objects on the server side. The skeleton finally calls the operation that was requested by the client. 10

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Middleware Tools Middleware Tools 12

Conclusion Conclusion Middleware was born for reuse by way of abstraction. Currently middleware research and development has reached a new phase. But the following questions are still open to resolve.  What kind of abstraction will we need in the next step?  Can we build a general model for all the middleware and customize the necessities to fit the applications when needed? 13

References  MIDDLEWARE-TECHNOLOGY-Seminar MIDDLEWARE-TECHNOLOGY-Seminar  technologies technologies   grid.ch/resources/middleware_tools grid.ch/resources/middleware_tools  bakken bakken 14