IPA IP 2020 Question 79

Topic: Computer Component

A question IPA Japan published in 令和2年度 10月 ITパスポート試験 公開問題 問79, translated into English. ITPEC is based on the same exams.

Same question on ITPEC: Nov 2021 Q13

Volatile memory loses its content when the power supply is lost. Among (i) through (iv) below, which of the following is the list of all volatile memory?

(i)DRAM(ii)ROM(iii)SRAM(iv)SSD

Explanation

(i) DRAM and (iii) SRAM — both are RAM, which loses its content when the power is cut.

  • •(i) DRAM stores bits as charges in capacitors, which leak, so it needs refreshing and forgets everything without power; it is used for main memory: volatile
  • •(ii) ROM keeps its content without power; it holds firmware such as the BIOS: non-volatile
  • •(iii) SRAM stores bits in flip-flop circuits, which hold only while powered; it is used for cache memory: volatile
  • •(iv) SSD stores data in flash memory, which keeps it without power: non-volatile

Answer (b)

Why not others:

  • •(a) — includes (ii) ROM, which is non-volatile, and misses SRAM
  • •(c) — lists exactly the two non-volatile memories, ROM and SSD
  • •(d) — includes (iv) SSD, whose flash memory is non-volatile, and misses DRAM

Key rule: RAM (DRAM for main memory, SRAM for cache) is volatile; ROM and flash memory (SSD, USB memory, SD cards) are non-volatile.

Computer Component · AI-written, may contain errors

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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.