問62
頻出度★☆☆
OS の仮想記憶方式に関する次の記述中の a～c に入れる字句の適切な組合せはどれか。 プログラムの実行時に，コンピュータの a 装置の b な容量に制約されない，c なアドレス空間を提供する。
令和7年度 ITパスポート試験 問62
テクノロジ系ソフトウェア › オペレーティングシステム
This question's explanation and your answers so far.
解説
問 62
- ア
正解 The virtual memory scheme is a mechanism that makes a program see an address space larger than the physical capacity of main memory (real memory). The OS uses auxiliary storage (disk) as an extension of main memory, and by swapping out (swap/page-out) content not currently in use to auxiliary storage, it provides a large logical address space that is not bound by the physical capacity of main memory. Therefore the blanks become a = main memory, b = physical, c = logical, and the combination that satisfies these is ア. The sentence "provides a c address space not constrained by the b capacity of the a device" can be read as 'a logical address space not constrained by the physical capacity of the device called main memory', which is consistent.
Incorrectイ
Although a = main memory is correct, b and c are reversed. What we want to be free from is the 'physical' capacity (b) of main memory, while what is provided to the program is a 'logical' address space (c). Making b logical and c physical inverts the meaning, so it is wrong.
Incorrectウ
The arrangement b = physical, c = logical is correct, but a = auxiliary storage is wrong. What constitutes the capacity constraint is ultimately the physical capacity of main memory (real memory). Auxiliary storage is the device used to make up for that constraint, so putting it in blank a as the 'object being constrained' is inappropriate.
Incorrectエ
a = auxiliary storage, b = logical, c = physical are all wrong. The object being constrained is main memory (a wrong), the constraint is physical capacity (b wrong), and what is provided is a logical address space (c wrong). As an explanation of virtual memory, every item is reversed.
ここがポイント
- Virtual memory uses auxiliary storage as a supplement to main memory, and is a scheme that provides a program with a large 'logical' address space not constrained by the 'physical' capacity of main memory.
- Distinguish that the object being constrained is the physical capacity of 'main memory' as real memory, while auxiliary storage is the device on the side that compensates for that constraint.
用語