What is the primary difference between RAM and ROM?

The primary distinction between RAM and ROM lies in their functions and characteristics in a computer system. RAM, or Random Access Memory, is designed for temporary data storage while a computer is in use. It provides fast read and write capabilities, allowing active processes and applications to quickly retrieve and store information. This transient nature means that all data in RAM is lost when the computer is powered off or restarted.

In contrast, ROM, or Read-Only Memory, is used to store firmware and other critical system instructions permanently. These instructions are vital for booting the system and managing hardware functions, and they are not lost when the power is turned off. The data in ROM is typically pre-written during manufacturing, which makes it resistant to being modified under normal operations.

This contrasts with some of the other options provided: RAM is not classified as non-volatile, and while it can be upgraded in some systems, the upgradeability does not fundamentally define its role compared to ROM's purpose of permanent firmware storage. Thus, the characterization of RAM as temporary storage and ROM as permanent storage serves to highlight their essential functions in computer architectures.