Microdata Corp. will get new letterhead.

Beginning Tuesday, the Newport Beach maker of business computer systems will be known as McDonnell Douglas Computer Systems Co., as part of an effort by Microdata’s St. Louis-based parent, McDonnell Douglas Corp., to give its subsidiaries names reflecting the corporate umbrella. Microdata officials said nothing will else will change about the company, which McDonnell Douglas acquired in 1979. But other McDonnell subsidiaries are being reorganized and renamed to reflect specific functions.