Bridge your legacy systems to the Web: Page 2

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MOM's way

Ace Hardware used middleware to connect its Web server to its database, says IT project leader Robert Blair. All of the company's product information, order entry facilities, billing systems, and so on are on an IBM mainframe. The Web server, by contrast, is on a Pentium server running Microsoft's Internet Information Server. Somehow, the two had to link.

One problem was that some of Ace's data is in flat files. "We have DB2, but we also have IMS databases," Blair says. That means ODBC, the usual method of linking Microsoft's Web server to other databases, wasn't open to Ace.

Middleware directory

Middleware methods

Database middleware, usually a product of the database vendors themselves, provides only database connectivity. However, much software finds the same functionality in the Open Database Connectivity (ODBC) standard.

Message-oriented middleware (MOM) is based on message passing and message queuing.

ORB middleware makes use of an object request broker, software that manages the relationship between clients, servers, and objects.

Remote procedure call (RPC) middleware sends a call from one machine or process to another machine or process for some service.

Transaction-processing (TP) monitor middleware is a layer of management logic between clients to control transactions as they move from one place to another. It ensures that messages from one device or process arrive at another.

Fortunately for Ace, Precise/CPE from Precise Software Solutions, based in Braintree, Mass., and Tel Aviv, was designed for exactly this kind of problem. The message-oriented middleware product provides a single API on Web and legacy systems, so the API looks like Java to Java applications and like ActiveX to ActiveX applications. When the resulting application exchanges messages with IBM SNA systems, it speaks in APPC. A request for data or a transaction can come into a Web server running Precise/CPE as a standard HTML-style communication, where it is turned into APPC and sent winging off to a mainframe. Now Ace's Web-using customers can access IMS data and have it come back to them as HTML files.

And Blair could do it all without spending decades writing code. "Using it is as easy as calling a subroutine," he says.

There's no shortage of MOMs on the market. IBM has been widely promoting its MQSeries as a MOM for the Web, and Digital Equipment has been saying the same about its DECmessageQ. Talarian offers SmartSockets MOM; Momentum Software says it has shipped over 100,000 copies of its X*=IPC. VCOM, originally developed by Swedish car maker Volvo, is now being actively marketed by Veri-Q. Even database vendor Sybase is introducing a MOM. A quick browse of the Message-Oriented Middleware Association's Web site shows many others and more coming.

Should you ORB it?

While MOM tends to show up in proprietary technologies, ORBs (thanks to the Object Management Group's efforts) are neatly standardized around the OMG's CORBA.

One potential threat to an ORB standard is that Microsoft and Digital support a non-CORBA ORB, DCOM. The possibility of two ORB standards has scared some users away from ORBs entirely. This is true even though Microsoft now seems to be backing away from DCOM as it revs up its marketing and development engine for the Microsoft Transaction Server, a.k.a. Viper, a TP middleware product that could give Microsoft ActiveX applications legacy connectivity.

Moreover, ORBs--by definition--are set up to deal with objects. This can be troublesome if you want to connect to non-object-oriented legacy systems. "The problem with most object-oriented solutions is that they expect objects at both ends of the pipe," says Chet Geschickter, vice president of marketing at Precise Software. "And that's not the case when you are trying to talk to legacy systems."

Despite these problems and the attractions to MOM, ORBs seem to have won the war for the hearts and minds of the industry. They are perceived as one of the fundamental pieces of the emerging standard architecture of Web-based corporate computing.

"When you look at Netscape with its Netscape ONE architecture, or Oracle with its Network Architecture, you see competing implementations of a very similar architectural vision," says Brian Croll, director of marketing for Sun's Solaris servers.

In that architectural vision, he says, you have several standard components. "You have Java on the desktop, and then on the server side, you have servlettes [server-side Java code]. Then you have IIOP, and finally, WebNFS."

Presumably, Microsoft would add ActiveX to the list along with Java. But it's the Internet Inter-ORB Protocol (IIOP) that's important. This is aCORBA-based protocol, promoted by the OMG, for communication between objects and applications, particularly on the Internet and within intranets.

IIOP suddenly became the de facto standard for object-related activities on the Web last July when Netscape announced that it would embrace the standard. It made IIOP part of its Netscape ONE architecture and licensed an IIOP-compliant ORB from Visigenic Software, the ORB-middleware vendor headed by Informix founder and database pioneer Roger Sippl.

The endorsement launched ORBs into intranet stardom. "It really gave the ORBs a shot in the arm," says one developer who asked not to be named. "After the OMG spent years getting everyone to standardize on CORBA, it all seemed to lose steam. Then along came the Web and WORBs [Web ORBs], and everything's back from the dead."

WORB vendors are booming. "All the former ORB suppliers are in the market," says Aberdeen's Stevens. "Anyone who was building distributed applications is now on the Web...with CORBA as the resounding ORB of choice." He cites in particular IONA Technologies, which has combined its Orbix ORB with Java to produce OrbixWeb.

Some ORB vendors are offering middleware packages that pair an ORB (not always CORBA-compliant) with another technology--usually a database. The result is a powerful middleware-development environment combination.

Late last year, OODBMS vendor GemStone Systems revealed that it was moving Webward. The Beaverton, Ore., company announced a CORBA-compliant ORB, GemOrb, along with products that give Web browsers and Java applications access to the GemStone OODBMS. Web applications talk to the GemStone DB, which in turn talks to legacy systems via GemOrb.

Computer Associates, which markets a proprietary ORB and TP monitor, also offers Jasmine, an OODBMS designed for multimedia and Web applications. A user can directly contact it via standard HTML or hook up through a Web server via a CGI gateway. Jasmine can then link to legacy systems via SQL. "This means that you can store new media, like video and graphics, in Jasmine, and still have access to older data in other databases," says Yogesh Gupta, senior vice president of product strategy at CA. For instance, a company could combine a database of employees with photos by putting the graphics in Jasmine and leaving the tabular data where it is. When a user calls up a record, the browser sends a request for it to Jasmine, which extracts the relevant data from the RDBMS, combines it with the photo, and sends the whole to the browser for display.

One ORB-Jasmine user is Financial Technologies, a New York City software company that develops financial applications for the securities industry. "The securities industry needs a lot of information on demand," says chairman and CEO Charles J. Lewis. "It often requires complex calculations and the integration of multiple bits of data. It is thus an appropriate use for objects."

But he also has to have relational data. "Behind the scenes, we've got a very robust set of applications on RDBMSs--Oracle on Sun and DB2 on IBM--that gather data from both market sources and back-office processes, things like accounting."

And then there's the Web connection. The users are Wall Street brokers who might want to view data with their browsers. This led Lewis to Jasmine. "We started development about a year ago," he says, "and we're still in the development phase."

Financial Technologies chose Jasmine because "we liked its pure object focus," Lewis says. "Some products attempt to combine relational and object functionality in the same product. We think that both technologies have their place, and we like vendors who focus exclusively on what they're really good at."

The more the merrier

ORBs and MOM don't have the field wholly to themselves. Other middlewares are aiming at your Web business, too. Gradient Technologies, for example, offers WebCrusader, a Web middleware based on the Open Software Foundation's DCE network environment and Java. Several companies, such as Sanga International, are looking at the Java Database Connectivity (JDBC) standard to improve database connectivity to the Web.

Basically, it all comes down to timing. In the very long term, the various attempts to create complete Web-based architectures for computing might turn Web-to-enterprise links into system-level functions. In the short term, the Web-link business seems to belong pretty firmly to MOM and ORBs, simply because the market is behind them.

But what about the medium term? Will either MOM or ORBs emerge as the dominant Web middleware? Probably not. In fact, the whole point may become moot, with MOM and ORBs continuing to blend into something like the MORB. Says Talarian's Laffey, "The ORB vendors are adding messaging to their ORBs, and we [MOM vendors] are adding bridges to ORBs. In two to three years, they're going to come together."


Links to related articles:

  • MQSeries tools take flight
  • Middleware: Link everything to anything
  • Middleware demystified
  • Getting distributed apps to communicate: Let's talk middleware

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