A Level Computer Science OCR Practice Exam

What role does the Data Bus play in a computer system?

1. It carries the clock signals

2. It transfers addresses to memory

3. It connects components to share data

4. It stores the next instruction type

The correct answer is: It connects components to share data

The Data Bus is a crucial component in a computer system as it facilitates data transfer among various components, such as the CPU, memory, and input/output devices. It acts as a communication pathway that allows these components to share data in a bi-directional manner, meaning data can be sent and received as needed. When the CPU needs to read data from memory or send data to an output device, it utilizes the Data Bus to transmit that information efficiently. The width of the Data Bus, measured in bits (for example, 32-bit or 64-bit), determines how much data can be transferred simultaneously, impacting the overall speed and performance of the computer system. The other options play different roles in the architecture of a computer. For instance, clock signals govern timing and synchronization but are not carried by the Data Bus. Address transfer is the responsibility of the Address Bus, which is distinct from the Data Bus and focuses solely on sending location information to access data. Lastly, instruction storage is typically managed in the CPU's instruction register (not the Data Bus), which holds the next instruction to be executed by the CPU. Thus, the correct understanding of the Data Bus highlights its essential function in connecting components to share data effectively.