A Level Computer Science OCR Practice Exam

In the context of CPU operations, what is meant by "fetch"?

1. Performing calculations

2. Receiving commands from the RAM

3. Retrieving instructions from memory

4. Storing executed data in RAM

The correct answer is: Retrieving instructions from memory

In the context of CPU operations, "fetch" refers to the process of retrieving instructions from memory. This operation is the initial step in the instruction cycle, which is fundamental to how a CPU executes programs. During the fetch phase, the CPU accesses a specific memory address where an instruction is stored, bringing that instruction into its instruction register for processing. This process is critical because the CPU must first obtain the relevant instructions it needs to perform any calculations or tasks. Once the instruction has been fetched, the CPU can then decode it and execute the required actions. Fetching ensures that the CPU has the correct sequence of operations to follow in order to execute programs effectively. Understanding this basic operation is key in grasping how a CPU interacts with memory and executes instructions sequentially.