What does 'latency' refer to in computer systems?

• A. The time taken to execute commands
• B. The delay before data transfer begins
• C. The speed of data reading
• D. The overall performance of a system

Answer: (B)

Latency in computer systems specifically refers to the delay before data transfer begins. This is an essential concept because it measures the time it takes for a system to respond to a request, highlighting how quickly data can move from one point to another in a network or storage device. For example, if a user sends a request to read a file, latency is the time taken from that request to the initial moment when data starts being sent back. Understanding latency is crucial as it can significantly impact user experience and the effectiveness of data-intensive applications, making it a key factor in system design and performance tuning.

The other choices address different aspects of computing: the time taken to execute commands relates more to processing speed than to latency; speed of data reading refers to how quickly data can be read once it starts transferring, and overall performance of a system encompasses many factors, including CPU speed, memory, and I/O operations, rather than focusing on the specific concept of latency.