Non-Volatile Memory Explained

The question asks to identify the type of computer memory that is non-volatile. Non-volatile memory is a crucial component because it means the memory can retain data even when the power supply to the computer is completely turned off.

Analyzing Memory Options

Let's look at each option to understand their characteristics:

• Virtual Memory: This is a technique used by operating systems to manage memory. It uses a portion of the hard drive to act as if it were RAM. While it helps run more applications, the data stored in the active virtual memory space (which resides in RAM or swapped to disk) is generally lost when power is off, although the persistent storage (hard drive) itself is non-volatile. It's not primarily a type of memory chip known for inherent non-volatility.
• Cache Memory: Cache is a small amount of very fast memory used to speed up access to frequently used data from the main memory (RAM) or storage. Cache memory is typically volatile, meaning it requires power to maintain the stored information. Data in cache is lost when the computer is turned off.
• ROM (Read-Only Memory): This type of memory is designed to store data permanently or semi-permanently. The key characteristic of ROM is that it is non-volatile. It holds essential system instructions, like the firmware needed to boot up the computer, and this data is retained even after the computer is turned off.
• RAM (Random Access Memory): RAM is the main working memory of a computer. It allows the processor to read and write data quickly. However, RAM is volatile memory. All data stored in RAM is lost when the computer loses power.

ROM: The Correct Choice

Based on the definitions:

• RAM is volatile.
• Cache Memory is volatile.
• Virtual Memory relies on other storage but isn't inherently non-volatile memory itself.
• ROM is non-volatile and retains data without power.

Therefore, ROM is the memory type that is non-volatile, meaning it retains data even after the computer is turned off.