Types of processor

The 'Types of processor' topic in OCR A-Level Computer Science explores the different architectures and designs of central processing units (CPUs). This includes the classic Von Neumann architecture, where data and instructions share a single memory bus, and the Harvard architecture, which uses separate memory and buses for data and instructions. Understanding these distinctions is crucial for grasping how computers execute programs, manage memory, and achieve performance gains through parallelism.

This topic also covers modern processor designs such as RISC (Reduced Instruction Set Computer) and CISC (Complex Instruction Set Computer), which represent different philosophies in instruction set design. RISC processors use simple, fixed-length instructions that can be executed in one clock cycle, while CISC processors have complex, variable-length instructions that can perform multiple operations. Additionally, you'll learn about pipelining, which allows multiple instructions to be processed simultaneously by overlapping their fetch-decode-execute cycles, and the challenges it introduces like hazards.

Mastering this topic is essential for understanding how processors work at a hardware level, which underpins performance analysis, system design, and optimisation. It connects to other areas such as assembly language programming, memory management, and parallel processing. By the end, you should be able to compare architectures, explain the trade-offs between RISC and CISC, and describe how pipelining improves throughput.