What memory type can only be read and cannot be changed?

The type of memory that can only be read and cannot be changed is Read Only Memory (ROM). ROM is designed specifically for storing firmware and other critical programs that should not be modified during regular operation. It retains its contents even when the power is turned off, making it essential for boot processes in computers and other electronic devices.

This characteristic of non-modifiability is critical for the integrity of the data stored in ROM, as it ensures that the essential instructions required to initialize hardware and start up the operating system remain intact and unchanged. Unlike RAM, which is used for temporary data storage and can be written to and read from, ROM serves a different purpose and is typically programmed during the manufacturing process.

On the other hand, Random Access Memory (RAM) and Volatile Memory are types of memory that allow both reading and writing, and their data can change as applications run. Cache memory is also used for fast access but is still writable and volatile. Thus, ROM stands out as the memory type that is immutable after its initial programming.