Tough Decisions for Old Apps
- By Stephen Swoyer
Web enabling or exposing mainframe applications to new and different constituencies—including non-mainframe applications—is supposed to be easy, provided organizations have prepared by separating their app’s business logic from its presentation logic.
Unfortunately, some industry watchers claim, that's not the case for many mainframe apps, forcing enterprise service-enablement initiatives to negotiate some fairly difficult roadblocks.
The situation isn't totally bleak. “There are a lot of people doing that already,” says Tyler Allman, a product manager with software tools vendor Compuware. “You look at client-server design techniques that came out of the ’80s—they effectively said that all CICS programs should be broken out into a couple of programs: one that would handle all of the screen-handling and prepare a message that would pass through to a [communications] area that would do all the work itself.”
Putting aside the vagaries of SOA, a design of this kind just makes good sense, says Mark Schettenhelm, QACenter mainframe product manager with Compuware. “It’s just a good design, regardless of [the architecture],” he says. At the same time, Schettenhelm acknowledges, separating an application’s business logic from its presentation logic also provides a starting point for organizations to expose—in native COBOL, if they want—mainframe application features and interfaces as part of an SOA.
Although most mainframe applications written in the late ’80s and later have probably been segmented this way, Compuware’s Allman stresses mainframe apps from the ’70s and mid-’80s have to be taken into account, too.
“I think [the application split is] pretty much half and half. It’s amazing how long applications live. When people write stuff and it works and it gets the business done, they keep it. It runs. It’s cheap. There’s a lot of stuff that was written in the ’70s and ’80s that is taking screen-based input—it’s all mixed up together, and that’s the stuff that you have to screen-scrape,” he comments.
According to Schettenhelm, the result is that even with the uptake of SOA, many orgs have put off deciding what to do about these apps. “I think a lot of the [service-enablement] technology is there and being adopted, and I think the people realize that the service-oriented architecture really makes sense and is the way to go, but it’s now making those hard decisions about what to do with these older applications,” he says.
Stephen Swoyer is a contributing editor for Enterprise Systems. He can be reached at firstname.lastname@example.org.