RAM can be read and written to anytime the CPU commands it, but <answer>ROM</answer> is preloaded with data and software that never changes, therefore the CPU can only read from it. <answer>ROM</answer> is typically used to store the computer's initial start-up instructions. In general, the contents of RAM are erased when the power to the computer is turned off, but <answer>ROM</answer> retains its data indefinitely. In a PC, the <answer>ROM</answer> contains a specialized program called the BIOS that orchestrates loading the computer's operating system from the hard disk drive into RAM whenever the computer is turned on or reset. In embedded computers, which frequently do not have disk drives, all of the required software may be stored in <answer>ROM</answer>. Software stored in <answer>ROM</answer> is often called firmware, because it is notionally more like hardware than software. Flash memory blurs the distinction between <answer>ROM</answer> and RAM, as it retains its data when turned off but is also rewritable. It is typically much slower than conventional <answer>ROM</answer> and RAM however, so its use is restricted to applications where high speed is unnecessary.
What type of memory can a CPU only read from?
ROM