ROM (Read-Only Memory)
Overview
ROM is non-volatile memory that contains permanent data or instructions. It is typically programmed during manufacturing and cannot be (or is rarely) modified during normal operation.
Detailed Explanation
Key Concepts
- Non-volatile: Retains data without power.
- Pre-programmed: Stored data is set during fabrication.
- Unidirectional: Read-only in most cases.
Characteristics
- Stability: High data retention.
- Speed: Generally slower than RAM for writes but fast for reads.
- Security: Data is permanently stored.
Applications
- Firmware storage.
- Boot-up instructions.
- Embedded system programs.
Examples
- Mask ROM: Fixed during manufacture.
- Field Programmable ROM variants may allow one-time programming.
Practice Problems
- Outline the advantages of ROM over RAM.
- Discuss the role of ROM in system boot-up.
- Compare Mask ROM with other programmable ROM types.
References
- Digital Design by Morris Mano
- ROM Overview