Which of the following is an example of non-volatile storage?

Non-volatile storage refers to any storage that retains data even when power is turned off. A hard drive is a prime example of non-volatile storage because it permanently stores data on magnetic disks, ensuring that information is not lost when the computer is powered down. This makes hard drives ideal for long-term data storage, as they can keep files, applications, and operating systems intact without requiring a continuous power supply.

In contrast, RAM (Random Access Memory) and cache memory are both types of volatile memory, meaning they require power to maintain the stored information. Once power is lost, any data held in RAM or cache is erased. Similarly, processor registers are small storage locations within the CPU that hold temporary data and instructions needed by the processor while it is powered on. However, once the power is turned off, any data in these registers is lost as well.

Thus, the hard drive stands out as the correct choice for non-volatile storage, as it fulfills the requirement of retaining data without a power supply.