Business Notes COMPUTERS

The world's largest computer maker has long shied away from the industry's most advanced field of all: supercomputers, the lightning-fast machines that can make billions of calculations per second. Last week IBM suddenly announced that it is souping up. In an unorthodox arrangement for a company that develops most of its projects internally, Big Blue plans to join forces with an outsider, Steve Chen, a leading supercomputer designer, to develop a machine for the 1990s that will be 100 times faster than today's speediest devices. Chen started his own tiny research company, Supercomputer Systems, of Eau Claire, Wis., only three months ago, after leaving industry leader Cray Research when that company balked at the $100 million cost of his next generation of machines.

The IBM-Chen venture aims to push into supercomputing's furthest frontier, a technology called parallel processing. Machines using that technique divide complex problems into pieces, which are then handled by scores or even hundreds of processors working simultaneously. The Reagan Administration is reportedly planning to endorse and underwrite research in the field, since the technology is crucial not only for such applications as weather forecasting and wind-tunnel testing but also for the President's Strategic Defense Initiative.