問69
頻出度★★☆
PC の省電力機能に関する次の記述中の a, b に入れる字句の適切な組合せはどれか。 PC の電源を切る直前の作業状態を補助記憶装置に保存しておき, 次に電源を入れたときにこの内容を読み出して電源を切る直前の状態に戻して使用可能とする機能を a という。 また, 作業を中断して省電力モードに移行する際, 移行直前の作業状態を主記憶装置に記憶し, 作業再開時に速やかに PC を移行直前の状態に戻して使用可能とする機能を b という。
平成23年度 特別試験 ITパスポート試験 問69
テクノロジ系コンピュータ構成要素 › メモリ
This question's explanation and your answers so far.
解説
問 69
Incorrectア
Standby in a is a feature that retains the working state in main memory, so its destination conflicts with a's wording “saves it into secondary storage” (standby is the term that belongs in b). Furthermore, mirroring in b is a technology typified by RAID1 that writes the same data redundantly to multiple magnetic disks to improve fault tolerance; it is neither a power-saving feature nor a feature for restoring the working state.
Incorrectイ
Striping in a is a technology typified by RAID0 that distributes data across multiple magnetic disks to speed up access; it is not a feature for saving the working state just before the power is turned off. Hibernation in b saves to secondary storage, which contradicts b's wording “stores it in main memory,” and because the data must be read back from the disk it also fails to meet the condition of restoring the state “quickly” (hibernation is the term that belongs in a).
- ウ
正解 The correct answer is ウ (a: Hibernation, b: Standby). Blank a describes the feature that “saves the working state just before the power is turned off into secondary storage (a hard disk or SSD), and on the next power-on reads that content back to restore the original state,” which is exactly the description of hibernation. The decisive point is that the destination is secondary storage, whose contents are not lost when the power is cut, so the working state is not lost even if the PC is powered off completely. Blank b describes the feature that “when shifting to power-saving mode, stores the working state just before the shift in main memory, and quickly restores the original state when work is resumed,” which is the description of standby (also called suspend or sleep). Because a minimal amount of power keeps being supplied to main memory to retain its contents, recovery is fast, but a small amount of power is consumed even while waiting. From the contrast of whether the destination is secondary storage or main memory, and whether recovery is slow but the state is held without power or fast but power is required, a = hibernation and b = standby are settled, and only ウ has this combination.
Incorrectエ
Both mirroring and striping are RAID technologies that define how multiple magnetic disks are used, so neither a nor b has anything to do with a PC's power-saving features. Mirroring aims to improve reliability and striping aims to improve performance; neither is a mechanism that saves the working state and restores it.
ここがポイント
- Hibernation (the hibernate state) is a method that writes the working state out to secondary storage and then cuts the power completely; power consumption while idle is almost zero, but recovery takes time because the data must be read back from the disk.
- Standby (also called suspend or sleep) is a method that waits with the working state retained in main memory; because main memory must keep being powered it consumes a little electricity, but recovery is fast. Mirroring and striping are RAID terms and have nothing to do with power-saving features — the question is set up to target that confusion.
用語