OCR A Level Computer Science (H446)Specification point 1.1.1

OCR H446 1.1.1: Structure and function of the processor

The free BugBot lessons that teach this point, a robot to try it on, and the past-paper questions that test it.

What it covers

At GCSE (F9.3) you met the von Neumann architecture: a processor, a memory that holds both the program and its data, and buses joining them. At A level you need the same picture drawn precisely: which components sit inside the computer, what each bus carries and in which direction, what exactly the stored program concept says, and when a designer would choose the Harvard architecture instead. This module then opens the processor itself, and it uses BugBot's microcontroller as the running example of a real embedded processor.

  • Hardware and software
  • The internal components
  • The stored program concept
  • Von Neumann and Harvard
  • The robot's processor
Read the free lesson (20 min)

Or do it in the simulator, with tasks that mark themselves

Lessons that teach it

  1. A9.1 Hardware, software and the stored program Computer architecture
    Internal components, the three buses and their widths, I/O controllers, the stored program concept, and von Neumann against Harvard.
  2. A9.2 The processor and its registers Computer architecture
    The ALU, control unit and clock, general-purpose and dedicated registers, and the status flags an 8-bit ALU sets.
  3. A9.3 The fetch-decode-execute cycle in detail Computer architecture
    Register transfer notation, the buses at each step, a full register trace, and a stored program that plays notes.
  4. A9.8 Performance, pipelining and parallel processors Computer architecture
    Cores, cache, clock speed, word length and bus widths; pipelining; CISC and RISC; multicore systems and GPUs.
  5. A9.10 Project: a processor of your own Computer architecture
    Build a von Neumann machine with register transfers, addressing modes, flags and memory-mapped I/O that plays a scale on the robot.

Try it on a robot

The task from A9.1 Hardware, software and the stored program, running here. Change the program and press Run.

The specification is OCR's own document; this page says which of our lessons teach point 1.1.1 and is not endorsed by the board.