A Level Computer Science OCR Test 2025 – 400 Free Practice Questions to Pass the Exam

The Current Instruction Register (CIR) plays a crucial role in the operation of a computer's control unit by storing the instruction that is currently being executed or the one that will be executed next. When the control unit fetches an instruction from memory, it is loaded into the CIR before it is decoded and executed. This process is essential for the CPU to understand which operation needs to be performed at any given time.

Understanding the previous options provides clarity on the specific function of the CIR. The option related to storing data to be processed is typically handled by different registers or memory, as the CIR specifically holds instructions rather than data. The choice concerning carrying command and control signals pertains to other components in the control unit that manage the flow of control signals during the execution of commands. Lastly, transferring data from RAM to the CPU is a function managed by buses and other registers, reflecting a different aspect of the CPU's operation in terms of data handling rather than instruction processing.

By focusing on the function of storing the instruction type of the next operation, it is clear that the CIR is pivotal for instruction management within the CPU, ensuring that the sequence and integrity of operations are maintained during processing.