EXHIBIT 4 SIGNATURE AUTHORITY [INTEL CORPORATE ADDRESS] [INTEL LOGO] March 7, 1997 TO WHOM IT MAY CONCERN: I will be out of the office on sabbatical from Monday, March 10 through Tuesday, May 6, 1997. In my absence, Peter N. Detkin, Director of Litigation, will have full signature authority. Sincerely, /s/F. Thomas Dunlap, Jr. - -------------------------- F. Thomas Dunlap, Jr. Vice President, General Counsel & Secretary