What best defines cache memory?

Cache memory is best defined as a small-sized volatile memory designed for fast access to data. Its primary function is to provide high-speed access to frequently used data and instructions, thereby improving the overall performance of the system. Cache memory is typically faster than regular main memory (RAM), allowing the CPU to retrieve data without having to access the slower storage options.

The reason why this answer is accurate lies in the characteristics of cache memory itself. It is a type of volatile memory, meaning it requires power to maintain the stored information, and it is located closer to the CPU than other types of memory, facilitating quicker data retrieval.

The other options do not accurately define cache memory. Long-term storage refers to devices like hard drives and SSDs that retain data without power, while data encryption involves securing information to prevent unauthorized access, which is unrelated to cache memory. Lastly, hard disk storage refers to a type of non-volatile storage medium, which is fundamentally different from the volatility and speed characteristic of cache memory.