What Is DCOM ???

[Operations]

CAN SOMEONE EXPLAIN TO ME WHAT IS - DCOM ???

please wright me a short explanation
and for what can i use it

[johnk]

This is a managers reply, not a technical reply.

Distributed Component Object Model is a way for the objects in OOP technology to find and communicate with each other. Instead of including a subroutine into a program, think of that subroutine as another program (object) which can be used by any other object (with authorization). The operating system accepts a communication from the calling program, finds the receiving program, and delivers the message. The receiving program may be on the same computer, on another on a LAN, on another on a WAN, or even can be found over the Internet. The reply to the calling program is similarly conveyed by the operating system.

We use it mainly for performance on a LAN. Instead of having to pass large recordsets over the network from the server to the client, the part of our program (a separate object)that reads through a recordset is deployed to the data server machine. Only the data which needs to be sent to the screen is transfered over the LAN to the client. There are many other ways that this distributed application architecture is important. Ultimately it is the architecture which will allow multiple small machines to replace very large ones, the perfromance and economic benefits are very large.

Microsoft owns DCOM. In Win2000 it is combined with MTS (Microsoft Transaction Processor) and other functions and is called COM+. Any application software vendor wishing the highest level of Microsoft Logo certification will need to use it.

There is a similar competing technology called CORBA. It is controlled by several large companies including IBM and Sun. I understand that it is not as mature as DCOM and that those of us working in Microsoft platforms are sure to use DCOM.

Pardon the long response. If anyone has an interest in continuing a discussion of OOP, DCOM and related issues I hope you will join in. It is thought to be an important way of the near future, yet not many seem to be discussing it.

John Kisner

[ehegarty]

Hi

I'm only new to DCOm as well and I have been looking into DCOM to connect to a remote host on a different network in order to read information from a database.

Would DCOM be the best way to go about this??

[S joy]

Hi johnk ,
I am totally newer to COM. I have read articles about it,just that's all.
I want to Create two Processes in two diffent machine in the same plaform and to communicate between these .
Could it be done through COM or DCOM ?

[johnk]

Hi, S Joy
As you may have seen, I am not a programmer. So my answers are from the view of a manager. Be sure and check out the details.

COM is used for communicting between objects on the same machine (or address space). DCOM (Distributed COM) is needed when the two objects are on different machines. It's the same application code, it's the job of Windows with COM or DCOM to connect them up.

Two suggestions for info: (1) The Duwamish Project on the MS MSDN site - it's a complete project with all code, and (2) the book "Doing Objects in Microsoft Visual Basic" by Deborah Kurata, Ziff-Davis Press. There are a number of excellant books, and we have found this one to be very good.

A note of caution to beginners in multi-tier programming. A number of things, large and small, must work together before anything works. Project management is a new world. Don't expect to get comfortable with OOP right away.

But when you get there, a whole new world opens up where many old boundrys are swept away.

Good luck.

John Kisner