Which type of memory contains instructions that cannot be modified or erased once produced?

Read Only Memory (ROM) is a type of memory that contains instructions which are permanently written and cannot be modified or erased under normal circumstances. This characteristic makes ROM particularly useful for storing firmware or software that needs to remain unchanged after manufacturing, such as the BIOS in computers.

ROM is utilized for critical tasks where software needs to be reliable and stable, as it ensures that essential startup instructions are always available. Unlike volatile memory, which loses its contents when power is turned off, or dynamic and static RAM, which are both types of volatile memory subject to change and loss, ROM maintains its data integrity without needing a power supply.

The immutability of ROM provides assurance that the system's foundational instructions will always be intact when needed, making it an essential component in various electronic devices.