Horizontally, it decided to layer its systems, in terms of apresentation, business logic and data organisation layer. It thenapplied different technologies to each layer. "This is so that ourdevelopers don't have to learn all sorts of technologies, only theones they are best suited for," explains Robless. Vertically, itstarted to break the infrastructure into components. "We built [theinfrastructure] in such a way that we could present them on anypresentation device and take data from any data device," says Robless.Different touchpoints were dealt with, including the Web, telephone,PDAs, PCs, and paper.

UAL also recognised that its legacy systems were still valuable anddidn't discard them. "They ain't broke, so we didn't fix them. We justbuilt around them. They are not going to go away. They have a lot ofdata in them and run just fine," says Robless.

When UAL started building services, it broke them down intoinfrastructure and business services. The former revolves around theapplication standpoint, including services for reservations, flightoperations and maintenance.