Diff between COM and COM+
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hi gurus, I would like to know the difference between COM and COM+. I would appreciate if could get a detail description of each one of these. And I want to know whether all the features of COM are there in COM+. Thanx in Advance, Ravi.
hi ravi.. actually com+ is a framework which enhances the usage and scope of com components. Its not a binary standard like COM or a next version of COM. Its just the next vrsion of MTS. In com, a dll is an inproc server. but by adding that inproc dll to the com+ framework we can make it out of process for scalability, almost similar to surrogates in com Hope u r more familiar with Vb than vc, So consider the case of vb com method UpdateSales, in which u uses the ado connection object for transaction handling. here suppose u call some other two, three methods within UpdateCustomer and these internal fns: also uses transaction. Her the internal functions commited the transactions inside. Then in the outer fn: suppose u want to roll back the transactions, tehn u can roll back only those transactions in the outr fn:, u can't roll back the transactions in the inner fns: that alredy got committed. But COM+ is smart enough to handle this situation. Just group all these COM methods into a single transaction in COM+. Suppose the outer method need a rollback , then COM+ will roll back the transactions alredy committed in the previous COM methods also. Not only thsi transaction handling.. Message queing, queud components, event subsscribing and lot more..... As a bottom line COM+ is for distributed, scalable thin client app development, the NextGen of Client-Server development paradigm.. rgds... mil0.
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hi gurus, I would like to know the difference between COM and COM+. I would appreciate if could get a detail description of each one of these. And I want to know whether all the features of COM are there in COM+. Thanx in Advance, Ravi.
Microsoft came out with COM, which was nothing but a specification. Components built in any language according to this specification can be used with a client in any other language. So the programmer does not have worry about creating a single executable, since the component is identified by means of GUID (Global Unique Identifier), a 128-bit number that is stored in the system registry, along with other relevant information, to uniquely identify the component COM+ In order for an enterprise application to be able to use COM, it has to have certain capabilities like: Authentication Object pooling Transaction management Support distributed architecture Microsoft came out with DCOM (Distributed COM) and MTS (Microsoft Transaction Server) so that the developers don't have to add these capabilities to their components. Using the above two technologies, they can concentrate on writing the business logic instead of the background plumbing for their components DCOM is an RPC (Remote Procedure Call) protocol used for communication between distributed components. Here the client makes requests to a proxy class on the local machine, which then delegates the call invisibly to a remote stub class installed on a remote machine MTS is integrated with Microsoft's Windows 2000 OS under the new name COM+. But COM+ isn't just MTS; it also includes a host of other services. MSMQ (Microsoft Message Queue Server), which was released around the same time as MTS, is also integrated with Windows 2000 under COM+. MSMQ allows for asynchronous communication between clients and servers, which absorbs the impact of server inaccessibility. Event Service was added so that server classes can asynchronously communicate event occurences to multiple clients. The Load Balancing Service automatically instantiates requested objects on the machine that has the most available resources in the server farm. i think you get bored of this but the theoritical facts are these. All the Best!
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hi gurus, I would like to know the difference between COM and COM+. I would appreciate if could get a detail description of each one of these. And I want to know whether all the features of COM are there in COM+. Thanx in Advance, Ravi.
Microsoft came out with COM, which was nothing but a specification. Components built in any language according to this specification can be used with a client in any other language. So the programmer does not have worry about creating a single executable, since the component is identified by means of GUID (Global Unique Identifier), a 128-bit number that is stored in the system registry, along with other relevant information, to uniquely identify the component COM+ In order for an enterprise application to be able to use COM, it has to have certain capabilities like: Authentication Object pooling Transaction management Support distributed architecture Microsoft came out with DCOM (Distributed COM) and MTS (Microsoft Transaction Server) so that the developers don't have to add these capabilities to their components. Using the above two technologies, they can concentrate on writing the business logic instead of the background plumbing for their components DCOM is an RPC (Remote Procedure Call) protocol used for communication between distributed components. Here the client makes requests to a proxy class on the local machine, which then delegates the call invisibly to a remote stub class installed on a remote machine MTS is integrated with Microsoft's Windows 2000 OS under the new name COM+. But COM+ isn't just MTS; it also includes a host of other services. MSMQ (Microsoft Message Queue Server), which was released around the same time as MTS, is also integrated with Windows 2000 under COM+. MSMQ allows for asynchronous communication between clients and servers, which absorbs the impact of server inaccessibility. Event Service was added so that server classes can asynchronously communicate event occurences to multiple clients. The Load Balancing Service automatically instantiates requested objects on the machine that has the most available resources in the server farm. i think you get bored of this but the theoritical facts are these. All the Best!