IPA IP 2024 Question 56
A question IPA Japan published in 令和6年度 ITパスポート試験 公開問題 問56, translated into English. ITPEC is based on the same exams.
In a PC, which of the following is the memory or storage medium whose stored contents are lost when the power supply is cut off?
Explanation
DRAM — the only volatile memory among the options: its contents disappear when the power is cut off.
DRAM (dynamic RAM) stores each bit as an electric charge in a tiny capacitor. The charge leaks away, so it must be refreshed many times a second, and without power it is lost at once. That is why it serves as a PC's main memory, fast and cheap per bit, while programs and data are kept on non-volatile storage and loaded into it when needed.
Answer (b)
Why not others:
- •(a) DVD-RAM — a rewritable optical disc; the data is recorded physically on the disc and stays without power
- •(c) ROM — read-only memory written at manufacture, used for firmware; it is non-volatile
- •(d) Flash memory — rewritable but non-volatile, keeping its data in floating-gate cells without power; it is used in SSDs, USB memory and memory cards
Key rule: RAM (DRAM and SRAM) is volatile; ROM, flash memory and discs (magnetic or optical) are non-volatile, even DVD-RAM despite its name.
Computer Component · AI-written, may contain errors
This question comes from the past questions IPA Japan publishes, translated into English by ITPEC Practice. ITPEC Practice is an independent study tool and is not affiliated with IPA or ITPEC. See the original paper (PDF) or Report an issue.