Today, Multitier-Tomorrow, Distributed Objects
The coming wave of client/server technology will use objects distributed across multiple computers on the network. Conceptually, distributed-object C/S systems are nothing more than multitier systems broken down into many, many very small components, all of which can be mixed and matched (in the best systems) to allow the creation of custom applications from common modular parts.
In effect, distributed objects are a combination of several multitier-computing systems in which both the client and the server application logic consist of many, finer-grained modules than today's all-too-often monolithic business-logic layer.
Take a look at a typical "fat client" application. Code runs to about a full megabyte or more just on the client side; you can expect at least the same size applications running on the server side.
But with distributed-object computing, you're talking about 10 or 15 modules of only 100KB each running on the desktop and eight or nine modules of another 100KB each running on the server. At that point, you'll likely stop calling these mini-apps "tiers" and start calling them objects or components.
One major benefit of moving to a distributed-object architecture in large, dispersed C/S systems is that it makes using distributed database systems a whole lot easier, says Gartner Group software management strategies VP Roy Schulte.
"Five years ago, people thought two-phase commit would make it possible to have all distributed databases with a single logical database structure. Now we know that's not going to happen. The issue with distributed data management is how to manage distributed databases--they're just too hard to design, manage, and maintain." Too hard, and mostly not happening.
Instead, newer technologies--replication, publish and subscribe, database middleware, remote procedure calls, and especially distributed objects--are making it easy to use dispersed databases in a logical structure that looks and acts a whole lot like a distributed database system.
Once you get to multitier computing and to distributed objects, then you can get at distributed data much more easily.