Diff between com dcom

hi
I need to be clear idea about COM and DCOM.
Can help me some one..?

one more doubt: diff between COM and COM+

Thanks

COM means the client & server are on the same PC. DCOM means the server is on one machine, the client is on a different machine, but on the same network.

COM is built on binary interfaces. There are a bunch of standard ones, like IUknown, IMoniker, etc. (making up a number here): :D
Let's say there are 35 basic standard interfaces in COM. In COM+ there are 42. If a box supports COM+, it must be able to support those extra interfaces. There are other changes, like how ActiveX .EXE files handle marshalling, for example.

right..

COM vs COM+

COM+ was designed with the large enterprise application in mind.. It is ideal for writing large distributed applications. it is based on COM + MTS (microsoft transaction server)..

The basic idea it that you can invoke an object on a remote server and access it like it was on your local machine. Useful for writing 3 or n tier applications..

It provides extra functionality:
Queued components
Events
Transactions and distributed transactions
Pooled components (when not written in VB).

COM+ components are whats called configured components. win 2k supports com+ (control panel, admin tools, component services).

hope that helps..

rgds
chris