What is the primary function of a data bus in a computer?

The primary function of a data bus in a computer system is to send and receive data between the CPU and other components, such as memory and input/output devices. The data bus is a crucial part of the computer's architecture, as it facilitates communication between the processor and the various parts of the system that store or process data.

When data is transferred, it travels along the data bus, which consists of multiple channels or lines that allow for the simultaneous transfer of bits. The width of the data bus, denoted in bits (such as 8, 16, 32, or 64 bits), directly influences the amount of data that can be sent or received at one time, thereby impacting the overall performance of the computer.

In contrast, the other options serve different roles within the computer system. Connecting the CPU to external devices relates to interfaces and ports rather than directly to the data bus's main function. Increasing memory capacity involves the system architecture and components, not the data bus per se. Finally, maintaining clock speed stability pertains more to the clock circuitry and synchronization within the CPU and the system, rather than the data transmission role of the data bus.