ITPEC IP October 2021 Question 13

Topic: Computer Component

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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