Stratus Computer Inc has hung out a Help Wanted sign. Its current chief executive Bill Foster, who’s been there since its founding in 1980 except for a brief hiatus at the end of 1995, has started a search to replace himself, saying it’s time for new blood in the company. He expects to have a successor in place by the end of the year. Foster would continue as chairman, working on strategic positioning. Stratus’ biggest market is telecommunications and its product line is heavily dependent on fault tolerance and Unix, but it has hopes for its high-end NT- based RADIO clustering system.