In 1967-1968, Robert H. Dennard, at the IBM Thomas J. Watson Research Center, invented the basic single-transistor, single-capacitor (1T1C) dynamic random access memory (DRAM) cell: each bit is stored as electrical charge on a capacitor, controlled by a single access transistor. This architecture, radically simpler and denser than earlier multi-transistor cells, enabled high-density, low-cost-per-bit semiconductor memories, replacing magnetic core memory. Dennard's 1T1C cell remains, to this day, the fundamental architecture of virtually all main memory (RAM) in modern computers.