CORBA for the Masses

Implementations of the Common Object Request Broker Architecture (CORBA) have been around for years. On the client side, it's supported in OS/2 Warp, OpenDoc for Warp, and the Mac OS, but not yet in Windows. Netscape aims to change that by bundling Visigenic Software's VisiBroker, a Java-based ORB that speaks Internet Interoperable ORB Protocol (IIOP), with Communicator as well as with the SuiteSpot 3.0 servers.

As Netscape users upgrade to Communicator, CORBA's installed base will skyrocket. To whom will this matter? Corporate developers. "CORBA has been more widely accepted than I had expected," says Laird Popkin, director of technology and architecture for Th e News Corporation's Internet services division. "Everyone is busy wrapping the ir legacy systems in CORBA IDL [interface definition language]." Why? Though complex, CORBA is a robust and open way to construct enterprise-class networked systems.

The Microsoft counterpart to CORBA, Distributed Common Object Model (DCOM), hasn't shipped yet for Windows 95. And when it does, "there will be a gaping hole in the middle of it," says Jamie Lewis, president of The Burton Group. "DCOM has no directory service, and won't until 1998." Lewis points out, though, that Netscape won't use the CORBA naming service but will instead create IIOP bindings to its own Lightweight Directory Access Protocol (LDAP) directory service. That's a pragmatic move. Full-blown CORBA is a heavyweight system. At this point, Netscape is wise to concentrate on just getting the plumbing widely deployed.

Taking the long view, Netscape's Marc Andreessen sees IIOP subsuming many of today's protocols as the Int ernet evolves into a sea of object services. If Netscape's FTP sites pump 10 million IIOP-compliant ORBs into circulation this year, the object-oriented Internet could happen sooner than most people think. But there have to be nearer-term practical benefits as well. Here are two:

Bundled ORB is trusted code. Richard Soley, technical director for the Object Management Group (OMG), points out that because Visigenic's ORB is part of Communicator's trusted code base, it can connect to CORBA servers everywhere. Normal Java components, by contrast, can connect only to their servers of origin.

IIOP makes a good target for firewall vendors. A big problem for the "groupware everywhere" vision is that even some of today's core protocols such as POP and NNTP don't penetrate some firewalls. The situation will likely get worse before it improves, as Internet Mail Access Protocol (IMAP), LDAP, and Internet Calendar Access Protocol (ICAP) come on-line. But if IIOP could encapsulate all these protocols, multiple proxies could consolidate into one on the firewall, and it would be a lot simpler to configure packet-filtering in routers. "If all you care about is the API, then let the IDL compiler build the protocol engines," says the OMG's Soley. What will you do until IIOP proxies become available? You can piggyback IIOP on top of HTTP, though no one pretends this will be very useful.