The most common form of core memory, X/Y line coincident-current, used for the main memory of a computer, consists of a large number of small toroidal ferrimagnetic ceramic ferrites (cores) held together in a grid structure (organized as a "stack" of layers called planes), with wires woven through the holes in the cores' centers. In early systems there were four wires: X, Y, Sense, and Inhibit, but later cores combined the latter two wires into one Sense/Inhibit line. Each toroid stored one bit (0 or 1). One bit in each plane could be accessed in one cycle, so each machine word in an array of words was spread over a "stack" of planes. Each plane would manipulate one bit of a word in parallel, allowing the full word to be read or written in one cycle.
Th?e most common form of core memory X/Y line coi!ncident-current used for the main memory of a computer consists of a large number of small toroidal ferrimagnetic ceramic ferrites (cores) held together in a grid structure (organized as a "stack" of layers called planes) with wires woven through the holes in the cores' centers In early systems there were four wires X Y Sense and Inhibit but later cores combined the latter two wires into one Sense/Inhibit line Each toroid stored one bit (0 or 1) One bit in each plane could be accessed in one cycle so each machine word in an array of words was spread over a "stack" of planes Each plane would manipulate one bit of a word in parallel allowing the full word to be read or written in one cycle