BUSINESS MEMO: TO UNVEIL NEW COMPUTER

IBM Corp. plans to unveil a more powerful mainframe computer this week. The computer will allow businesses to process more information for a lot less money than existing older models, industry sources said. The new IBM computer is a heartier version of a System 390 model introduced by IBM in September -- processing the same amount of information up to 10 percent faster. The System 390 models are the third generation in a redesigned series International Business Machines Corp. launched in 1994...