The latest addition to the central computer complex at CERN back in 1969 was a CDC 3100 to be used in the FOCUS development project. FOCUS was an acronym for 'Facility for On-line Computations and Up-dating Services'. Its main purpose was to serve as the manager of the data-links to the central computers, the CDC 6600 and the CDC 6400, coming from the smaller computers which were being used on-line to electronics experiments. The CDC 3000 series computers from Control Data Corporation were mid-1960s follow-ons to the CDC 1604 and CDC 924 systems. Over time, a range of machines were produced - divided into the upper-3000 series and the lower-3000 series. CDC phased out production of the 3000 series in the early 1970s.