Software AG of North America Inc. has tapped the marketing resources of one of its strongest competitors in the field of systems software development, naming E. Linwood Pearce to be the marketing and sales "architect" for the Reston firm.

Pearce, 40, was the former vice president in charge of North American marketing and sales for Applied Data Research Inc., a $150-million-a-year software development firm recently acquired by Ameritech Inc.

At Software AG, a developer of software for large "mainframe" computers, Pearce will become executive vice president in charge of marketing and sales. The new post is next in line after President and Chief Executive Officer Stuart J. Miller.

"Pearce has a proven track record in our industry," Miller said. "His company has been very successful in the past couple of years. We think he will bring well-established experience and will add to the success of this company."

Pearce's selection follows a spate of other appointments in recent weeks, including that of Carlton B. Crenshaw, the former vice president for strategic planning at Sperry Corp.'s information systems group, to the new post of chief financial officer.

Software AG also recently promoted Gilbert Markbein, previously treasurer and controller, to the post of vice president. He will continue to have responsibility for the finance department. Markbein will report to Crenshaw. And Jeffrey I. Pollack, who has held a variety of sales posts, has been promoted to the post of vice president in charge of co-marketing, reporting to Pearce.

"Since we're experiencing significant growth in sales, it means a natural expansion in our personnel and in our operations," Miller said. BANKING, FINANCIAL SERVICES

The National Bank of Washington recently announced the promotion of four senior vice presidents to executive vice presidents: Kathleen W. Collins, legal and trust divisions; Patrick G. Hartley, finance; William V. White, consumer banking; and William D. Wooten, corporate services.

National Bank of Commerce has elected Carlton P. Alexis to its board of directors. Alexis, vice president for health affairs at Howard University, heads the university's hospital and medical and dental schools.

CFS Financial Corp., the holding company for Continental Federal Savings Bank, has named Albert J. Dwoskin to the board of directors of both the bank and the corporation. Dwoskin is president and owner of A. J. Dwoskin & Associates Inc., a Fairfax real estate firm.

Jefferson Bank and Trust Co. in Capitol Heights has named James J. Smat vice president and senior loan officer. Recently a commercial loan officer with Baltimore Federal Financial FSA, Smat will be responsible for managing all loan operations, including new business development. In addition, Peter A. Bozick, a former state senator and president of a wholesale beer distributing company, and Vincent D. Palumbo, chairman of the department of oral surgery at Southern Maryland Hospital, have been elected to the bank's board of directors. PROFESSIONAL SERVICES

Research Applications Inc., a management consulting firm, has appointed Barrie K. Friedman president of the Rockville company. Research Applications designs and conducts surveys for the government and private-sector clients.

Interspace Inc. in Arlington has appointed Douglas E. Deremer as regional vice president of the firm's Washington design division. He was formerly principal in charge of the Washington and New York offices of EPR Inc.

Stephen D. Harlan, the managing director of Peat, Marwick, Mitchell & Co.'s Washington office, has been elected to the firm's board of directors.