Web Applications: Middle-Tier Migration

While the rise of Web servers and thin clients garnered all the attention, middleware quietly reinvented itself. For years, middleware worked on the back end, exchanging apps between databases and hosts. Now, middleware servers are a critical part of any modern e-commerce system, occupying the middle tier, where the business logic that runs and manages Web sites resides. Companies that happily built two-tier systems to link fat clients to even fatter back-end hosts are now scrambling to migrate application code to midtier Web and application servers.

The Swiss Colony Co., best known for its mail-order holiday baskets, boasts of a successful migration journey--and for good reason. The 73-year-old company installed its first mainframe, an IBM 1401, in 1963.

Up until recently, Swiss Colony had a classic two-tier design, with PCs running applications that communicated with the company's IBM 9672 mainframe. To make matters more complex, many of the company's sales and production processes date back to the 1920s. So, integrating its Web site into its enterprise network without reworking the sales order, credit card processing or food production systems was far from easy.

"We started with IBM tabulators and punch card sorters back in the mid-1940s," says Hans Bernet, manager of special products. "Our home-built systems work great, but we can't catch up to the Web all at once."

Swiss Colony hired Evergreen Internet Inc. to manage the integration job. The task at hand: Orders and credit card information from Swiss Colony's Web site must fit into the company's existing data-entry formats and be sent to a homegrown authorization system.

Gary Jones, a programmer at Swiss Colony for more than 25 years, says Evergreen is using the Extensible Markup Language (XML) to translate queries from online customers into the proper format for Swiss Colony's mainframe. The translated queries pull data from the mainframe, are sent back to the Web servers in XML format and are displayed in real time via eXtended Style sheet Language.

"This is the third wave of e-commerce tools," says Dave Clare, vice president of business development at Evergreen. "Application server agnostic, the tools in our ECentials software use standards, especially Java and Enterprise JavaBeans, to support multiple application servers at once."

The migration effort is paying off in a big way for Swiss Colony. "The Web is a wonderful way for customers to place orders with us and for us to communicate with customers,'' says Swiss Colony's Bernet. "The whole company is turning into a Net company, whether we planned it or not. It's just happening.''

Middlesex Hospital/Health System, which serves 23 towns in Middlesex County, Conn., also added a middle tier, but it handled the integration in-house.

Kevin Trask, a software engineer at the hospital, says the medical group started its Clinical Information System as a two-tier system in 1994, using a database from Progress Software Corp. running on HP/UX on an HP 9000 series Unix host. In early 1998, the hospital started converting to a three-tier model. It's running Progress' WebSpeed transaction server on top of Microsoft Windows NT Server 4.0 with Internet Information Server. "WebSpeed is our middleware, and we copied most of the business logic from the earlier Progress database to the Web server," says Trask.

Progress Consulting Services provided early training help and a jump-start for the hospital, but getting the expertise in-house was helpful, says Trask. "We filled in all the details and added more features."

Programs that access patient records, used since 1994, control the Web server and communicate with the previous Progress database; that database stores the data on the original HP system.

To maintain the confidentiality of medical records, the nearly 100 sites in the hospital system are on a private, leased-line network. All user actions are processed by the Web server, but are then transferred to the HP 9000 host for actions against the actual data records. Results are passed back to the Web server and formatted for display to the user by the application's browser interface. The browser interface reduces training needs, since most users have been on the Web to search medical reference sites.

Another player in the migration game is Candle Corp., which last year rolled out its Roma Business Service Platform. Roma is a middleware software layer that supports communications across an enterprise network and works with middleware infrastructure messaging products like IBM's MQSeries.

"There are lots of tools and services in place now to help migrate to a three-tier architecture," says Steve Craggs, vice president of enterprise application integration at Candle. "But the majority of [organizations] need help making these things work."

The state of North Carolina is using Candle's Roma products to integrate its 23 executive branch agencies. Applications being written at the agencies query existing data on incompatible systems. The Roma middleware speeds development time by eliminating the need to develop custom interface programs for each new agency application.

"We consider Roma a common backbone that all departments can connect to," says Emilie Schmidt, the state's chief technical officer.

State programmers used Roma during a nine-month pilot to cross-check driver's license data when issuing a new hunting license. North Carolina driver's license holders now get hunting licenses approved more easily, since the agencies share previously incompatible data through the new system.

Here's how the query application works: The state's Motor Vehicle Division uses an IBM ES 9672 mainframe. When the Wildlife Resource Commission processes a new application, it sends out a query via the Roma middleware to the Motor Vehicle

Division's mainframe. The query checks for three types of information--name, date of birth and address--and then verifies whether the person has a valid state driver's license. This midtier link to the driver's license database also is used by the state Department of Corrections to confirm that prisoner driver's licenses have been revoked. In addition, the state's Department of Labor now uses the driver's license database to screen for minors.

Since Microsoft powers nearly all corporate desktops, Windows NT has become a popular Web and application server choice for many companies moving to a midtier strategy. Yet the move to NT servers in the middle is a move away from client machines for many applications.

"Companies have learned that Web-based applications can be revised more frequently than desktop applications, plus they are cheaper and easier to maintain over time," says Susan Warren, product manager for Microsoft's Visual InterDev 6.0. Rolling out Windows client applications takes time at each desktop, but putting a new app on a Web server eliminates the need to change client software.

But the immature mix of products and services offered by vendors is complicating the process. Often, a single company provides both the tools and services, since they are the most experienced help available. The migration tools market is so new, vendor companies can't stop running long enough to gauge the market.

"Many customers do projects internally and have enough expertise to make it work with just a little help," says Scott Dietzen, chief technical officer for the WebXpress division of BEA Systems Inc.

Yet, he says, "traditional, nontechnology companies need more help. One-third of our revenue is from services, and we can't cover the demand."

Evergreen's Clare sees the same situation with his customers. "We started in 1996 doing strictly services,'' he says. "In 1998, we made the move from pure services and started selling our 15 modular e-commerce products. All are in Java and Enterprise JavaBeans for use in the middle tier."

One of the big challenges companies face when integrating Web apps into existing client/server systems is connecting legacy stovepipe apps. In the past, these connections typically had proprietary interfaces to both systems, making them inflexible. Many vendors are now offering tools that deliver better cross-platform communication.

IBM's upgraded MQSeries messaging software, announced in mid-June, supports XML and Java Messaging Service, the developing standard for enterprise messaging services. "We provide base messaging services between 35 different operating systems and server platforms," says Rob Lamb, business unit executive for IBM's MQSeries. MQSeries also provides a rules and formatting engine for transferring data, Lamb says.

Of course, the ultimate goal of building a three-tier architecture is to move the business logic away from the clients. In a client/server system, that logic sits behind the user interface; but, in a three-tier system, the business logic resides on a Web server, where it can be shared.

Microsoft's Warren stresses the importance of keeping business logic and data separate from the user interface. "Programmers are learning how to reuse middle-tier objects, especially COM," says Warren, referring to the Component Object Model software architecture from Microsoft.

"Customers are turning the corner on the philosophy of security and Web exposure," says Warren. "They are now much more sophisticated with security options, such as logging in to various server pages. Many are looking to expose Web applications to partners through extranets."

The location of the business logic, the rules that process data to fit the company needs, becomes even more critical when extranets link trading partners. "It's too expensive to have multiple portals and support multiple external system connections into a company," says Bob Gleason, CEO of Riverton Software Corp., which provides application framework and software code for middle-tier apps. "Companies need a sense of order and control, and a flexible architecture to support e-commerce."

Yet roadblocks remain between the two-tier present and three-tier future for some companies.

Jennifer Kotzen, manager of Sybase Inc.'s Internet Application Division, works with companies handling migration themselves and those that are using Sybase's Enterprise Services. Kotzen sees four potential roadblocks for companies:

First, companies can't replace their old client/server systems, so they must share the business logic with the new apps. Both systems will coexist for a time. Second, integrating back-end systems, such as legacy mainframe data and enterprise resource planning apps, is a challenge because the data formats are incompatible and must be translated. Third, companies must learn to deal with the new application systems they're building. Finally, there are limited people resources to handle all the new projects confronting corporate IT.

Rachel Helm, director of technology strategy for integration software vendor CrossWorlds Software Inc., also has experience working with businesses migrating to three-tier architectures.

"Every customer and prospect has some kind of legacy application to deal with," Helm says. The recent development of migration tools causes other problems for customers. "Distributed systems are more difficult to manage," she says. "There are a lot of competing systems, but no centralized standard for system administration."

Helm echoed the sentiments of many vendors helping companies implement new solutions. "Legacy systems weren't built to communicate with external applications," she says. But good news is coming.

"We're getting to a critical juncture now, with the catalyst of cheaper, faster networks and lots of integration technology out there. The growth of e-business and the speed with which people have to change now are compelling companies to get business and technology moving forward," Helm says.

Make no mistake: The e-commerce explosion is making the middle-tier migration a journey most IT shops must take. While nobody really knows for sure where the journey will lead, what's clear is that now is not the time to turn back.

James E. Gaskin is a freelance computer journalist based in Mesquite, Texas. He can be reached at james@gaskin.com.