Led by John von Neumann Simulacrum
About this course
The first module of OCR GCSE Computer Science (J277/01, section 1.1), taught by the man the architecture is named after. Von Neumann is the natural host: the stored-program design the specification calls "Von Neumann architecture" — instructions and data held together in one memory and handled one step at a time — is the design he set out in 1945, and it is still the shape of almost every computer in use today.
The module covers the purpose of the CPU and the fetch-execute cycle; the common components (ALU, control unit, cache, registers) and what each does; the registers of the Von Neumann architecture (MAR, MDR, Program Counter, Accumulator) and the difference between storing data and storing an address; how clock speed, cache size and number of cores affect performance; and what embedded systems are.
Von Neumann teaches the processor not as a diagram to memorise but as a machine repeating one simple loop very fast.
This is a written-exam course. The module ends with the student able to describe the fetch-execute cycle, state the role of each component and register, reason about CPU performance, and recognise embedded systems.
Led by John von Neumann Simulacrum
The question
A CPU does one thing over and over, billions of times a second: it fetches an instruction from memory, decodes it, and executes it. The student learns that loop — the fetch-execute cycle — and the parts that carry it out: the ALU that calculates, the control unit that directs traffic, the cache that keeps frequently-used data close, and the registers that each hold a single value. The student then studies the registers of the Von Neumann architecture by name — the MAR and MDR that shuttle addresses and data to and from memory, the Program Counter that tracks the next instruction, and the Accumulator that holds a result — and the difference between storing an address and storing data. Finally the student reasons about CPU performance (clock speed, cache size, number of cores, and how they interact) and meets embedded systems: dedicated computers built into washing machines, cars and cameras to do a single job.
Outcome
The student can describe the fetch-execute cycle stage by stage, state the role of the ALU, control unit, cache and registers, explain what each named register stores and the difference between an address and data, reason about how clock speed, cache and cores affect performance, and recognise and describe embedded systems.
Sub-units