Inside every company live systems that, although built on old technology, are core to the business and can't be migrated easily to more modern software or hardware. That's the nature of IT. Build and install an application today, knowing that in five or eight tomorrows, the technology will be outdated.

Project managers try to choose technology they think won't get obsolete quickly or one that future products can link to. Crystal ball stuff like that is tough and no one predicts accurately all the time. Even today's modern SAP or Oracle enterprise resource planning suite will be a legacy system someday.

Disney is trying to come at the problem another way: making business and IT people involved in project planning aware that, eventually, the technology they're using will have to be replaced. So that at the same time they're planning what to build, the project team can also plan how and when to take it apart.

"I tell business people that putting in a system is like pouring concrete. You're going to need a lot of jack hammers to get it out someday, and this is the opportunity to plan for that," says Steven P. Davis, chief architect and vice president of IT at Walt Disney Studios, a $US9 billion movie company that's part of the $US34 billion Disney entertainment empire.

Davis wants to classify every IT product at Disney as emerging, under evaluation, core or declining. "Domain leads" inside Disney -- subject matter experts in, for instance, servers or application software -- are assigned to write research papers about their technologies, to identify what's declining. These papers are then released in the fall, a couple of months before Disney's annual business planning cycle begins in December, Davis says. Davis spoke at the Society for Information Management's annual conference in Memphis in October.

That's enough time to get it in front of the planners before project decisions are made, he says. Some technologies, such as server software, are assessed annually. But others are moving so fast that quarterly reviews are the norm, for example, BlackBerrys, other PDAs and smartphones.

Once hardware or software is labelled declining, something must be done about it.

One rule Davis has is to keep within one version of the latest iteration of a piece of software. For example, if the most recent full version of Microsoft's database is SQL Server 2005, Disney will run no more than one version behind -- SQL Server 2000. When SQL Server 2008 arrives, expected this (northern) spring, Disney, presumably, will step up the trudge migrating its databases from 2000 to 2005.