Now that AT&T Co is phasing out its proprietary 3B Unix machines- and only making a part of its personal computer requirement – with everything new bought in, the company has a lot of surpluscomputer development staff. Accordingly, it is reassigning 100to 150 people working on computer development at Bell Laboratories to other work there. It is also merging the sales, serviceand technical support operations in its computer division at a cost of 500 jobs, reducing staffing to 8,500 from 9,000. Some jobs will be shed by attrition and reassignment, but lay-offs are expected to complete the reduction by the end of September. AT&T already made similar cuts earlier this year.