ROM concept check: Read-only memory (ROM) is a memory type in which data are stored permanently or semi-permanently and are not lost when power is removed. Assess this statement.

Introduction / Context:
Digital systems use both volatile and nonvolatile memories. ROM-class devices hold code and configuration across power cycles. Understanding permanence clarifies design choices for boot firmware and configuration storage.

Given Data / Assumptions:

• ROM includes mask ROM, PROM, EPROM, and flash when used read-only.
• “Semi-permanent” recognizes erasable types (EPROM/flash) that retain data without power but can be reprogrammed by special procedures.
• We discuss data retention, not write mechanisms.

Concept / Approach:
In ROM families, bits remain stored without power (nonvolatility). Mask ROM is factory-programmed and fixed. PROM is one-time programmable by blowing fuses. EPROM and flash are field-programmable and erasable (UV or electrical) but still nonvolatile between power cycles. Hence the statement is accurate.

Step-by-Step Solution:

Verification / Alternative check:
System block diagrams show ROM/flash holding firmware that persists across reboots, unlike DRAM/SRAM which clear on power loss.

Why Other Options Are Wrong:

• Incorrect: Would deny nonvolatility.
• Only true for RAM / Applies only to EEPROM: RAM is volatile; EEPROM is a subset of erasable nonvolatile memories, not the only ROM type.

Common Pitfalls:
Using “ROM” to mean only mask ROM; ignoring that flash used read-only still qualifies functionally as ROM in many contexts.

Final Answer:
Correct