von Neumann architecture
Most computers use the stored-program concept designed by Hungarian mathematician John von Neumann. In it, you store programs and data in a slow-to-access storage medium (such as a hard disk) and work on them in a fast-access, volatile storage medium (RAM). This concept, however, has an attendant bottleneck: it's designed to process instructions one after the other instead of using faster parallel processing.
See also: RAM