Read-Only Memory (ROM)
ROM is a device that allows permanent storage of information. It is Non-Volatile Memory.
ROM is used as Primary Memory because it stores the firmware / BIOS, which is essential for hardware initialization and system boot-up.
- It is non-volatile and read-only, designed for permanent storage of critical instructions.
- ROM is not used as secondary memory, which is typically for user data storage and is both writable and larger in capacity.
why isn't ROM used as secondary memory?
ROM isn’t used as secondary memory because it’s designed for permanent storage of non-changeable data. Secondary memory is meant for large-volume storage that can be rewritten and updated frequently.
Implementation Technologies
- Programmable Read-Only Memory (PROM)
- Contains fuses giving logic value of 1 to all bits in device. Programming means “blowing” fuses to give some bits a logic value of 0.
- Erasable PROM (EPROM)
- Can be erased by exposure to UV Light
- Electrically Erasable PROM (EEPROM)
- Read-write Memory (RW)