Operating on the principle of the last in, first out buffer, Digital Equipment Corp yesterday bade farewell to IBM Corp alumnus Ed Lucente, who resigned as the deeply troubled company’s head of worldwide sales and marketing. He is being replaced by Enrico Pesatori, head of personal computers. Chairman Robert Palmer wrote to shareholders trying to reassure them that he has everything under control and said he intended to accelerate the next phase of Digital’s turnaround strategy, a phase that will take two years. But we do not intend to alter our single, ongoing strategic focus on open client-server systems that deliver solutions.