A diagram of computer core processor 451, element 0299 infested with nanites
A computer core processor was a piece of hardware found in Federation computer systems which performed computations inside computer cores. They were segmented into elements.
Computer core processor 451 was one such piece of hardware and was located in the computer core of the Galaxy-class USS Enterprise-D. In 2366, Lieutenant Commander Geordi La Forge requested a cross section of processor 451, elements 0200 to 0300 for examination after bypassing the computer core to get power, and discovered a lesion, some kind of continuing disintegration. It was eventually discovered to have been caused by nanites. Lieutenant Commander Data later pulled up a diagram of processor 451, element 0299 which was infested with nanites. (TNG: "Evolution")