Please suggest me a site where i can get information about the basics of COM/DCOM or if you yourself can tell me then that would be great to.
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Here you are a tutorial

You should also check the MS site, and the MSDN library.

You can even learn about COM from VB help.  DCOM is a sort of multi-machine version of COM.  Also known as CORBA

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial

COM stands for Component Object Model.
They can be written in any language but the compiler needs to compile in a binary compatible format. This is because, it should run in any environment.

When this object is invoked, a system process gets the request and this loads this object and links this to the caller and the system process takes his hand off.

It should not depend on where the physical object is located, so the registration process comes. All COM objects are given a unique GUID across the systems. (I do not how this happens?). Each interface is given an id. The system process explained earlier, uses these to load the object and connect to the caller.

Why do we need COM objects. Earlier when DLLs were written in standard fashion all functions have an ordinal position. When we add a new function you might screw up the ordinal positions of the functions and this will make to you recompile all your programs which calls this DLL.

This problem is resolved in COM objects. Of course, you still have to recompile the calling programs should you change the name of the methods in the interface, add, change or delete the parameters in the function, change the return value.

You can avoid recompiling the calling programs, if you have only change to the body of the function. Set the Binary Compatible property. This will not change the GUID and Interface ID.

Hope this helps. Please let me know, should you need more assistance in this.

It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Visual Basic Classic

From novice to tech pro — start learning today.