Programmable Read-Only Memory (PROM) volatility — are PROM devices considered volatile (i.e., do they lose data when power is removed)?

Introduction / Context:
PROM (Programmable Read-Only Memory) is a one-time programmable non-volatile memory technology. After programming (typically by blowing fuses or altering antifuses), the stored pattern persists without power. Understanding volatility is critical when selecting components for firmware storage or configuration data that must survive power cycles.

Given Data / Assumptions:

• The statement suggests PROMs are volatile.
• PROMs retain programmed state when Vcc is removed.
• We discuss classic PROMs, not RAM-based “emulated PROMs.”

Concept / Approach:
Volatile memories (SRAM, DRAM) lose content without power. Non-volatile memories (PROM, EPROM, EEPROM, Flash) preserve content because their storage mechanism does not rely on power to maintain state. PROM uses irreversible physical changes to store bits; therefore, it is inherently non-volatile and does not require refresh or backup power for retention.

Step-by-Step Solution:

Verification / Alternative check:
Check PROM datasheets: they specify data retention (often 10–20 years or more) independent of applied power, confirming non-volatility.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing “programmable” with “volatile”; assuming all chips that can be written are RAM-like. PROM is write-once, read-many and non-volatile.

Final Answer:
Incorrect — PROMs are non-volatile