64-bit system sharpens Air Force eye in the sky

The Air Force's Joint Surveillance Target Attack Radar System resembles the more familiar Airborne Warning and Control System radar plane, but instead of surveying airspace, the Joint STARS Boeing 707 scans the ground for vehicles and potential targets. Radar information is processed by a central computer, which provides data to a bank of 18 consoles that overlay the radar data on maps. The data is analyzed and used to dispatch fighters to attack ground targets. The system was originally based on the classic Digital Equipment Corp. VAX minicomputer system, but has recently been upgraded to Compaq Computer Corp.'s 64-bit Alpha hardware, according to Alan Metzger, chief engineer for the Joint STARS development and support program for systems integrator Northrop Grumman Corp.

The digital photos taken of targets were getting too large for the old 32-bit system to handle, he said. "We have images that approach the limit of 32-bit address space."

"The old system was running at 70 percent of processor capacity, while the 64-bit Alpha system is at 14 percent," said Jim Kuhn, systems engineer on the computer replacement program for Joint STARS. "It is basically idling now, where it was running at capacity before."

Other performance improvements include a display response time reduced from 11 seconds to just 1 second, and a system boot-up time cut from 45 minutes to 15 minutes. The use of commercial off-the-shelf hardware has made the Joint STARS program less expensive and has accelerated the adoption of faster computers, Metzger said, adding, "The days of enormous development times are gone." Compaq's decision to migrate its Alpha systems to the Intel Itanium chip will only help that process. "We expect the same benefits from Intel's 64-bit processors," he said.