問74
頻出度★☆☆
32ビットCPU及び64ビットCPUに関する記述のうち, 適切なものだけを全て挙げたものはどれか。 a 32ビットCPUと64ビットCPUでは, 64ビットCPUの方が取り扱えるメモリ空間の理論上の上限は大きい。 b 64ビットCPUを搭載したPCで動作する32ビット用のOSはない。 c USBメモリの読み書きの速度は, 64ビットCPUを採用したPCの方が32ビットCPUを採用したPCよりも2倍速い。
平成30年度 春期 ITパスポート試験 問74
テクノロジ系コンピュータ構成要素 › プロセッサ
This question's explanation and your answers so far.
解説
問 74
- ア
正解 Only statement a is correct, so the answer is choice ア, which lists only a. A CPU being 32-bit or 64-bit refers to the width of data it can process at once (its register length); the number of address bits generally corresponds to it, which decides the theoretical upper limit of memory space. With 32 bits the limit is 2 to the 32nd power (about 4G bytes), while with 64 bits it becomes 2 to the 64th power, which is orders of magnitude larger. Therefore statement a, that a 64-bit CPU has a larger theoretical upper limit on the memory space it can handle, is appropriate, and choice ア, which contains only this, is the answer.
Incorrectイ
Choice イ is the combination of a and b, but b is wrong. A 64-bit CPU has backward compatibility and can also run a 32-bit OS (in fact, 32-bit operating systems have long been used in many environments), so the claim that there is no 32-bit OS that runs does not hold. Choice イ, which contains the wrong statement b, is inappropriate.
Incorrectウ
Choice ウ is the combination of b and c, but both are wrong. As stated above b does not hold, and c is likewise wrong: the read/write speed of a USB memory is determined by the USB standard and the performance of the storage device, and there is no relationship whereby it doubles because of the CPU bit width. It also fails to contain the correct statement a, which makes it inappropriate as well.
Incorrectエ
Choice エ lists only c, but c is wrong. The read/write speed of a USB memory depends on the connection standard (such as USB 2.0 or 3.0) and on device performance, and there is no fact that it becomes twice as fast just because the CPU is 64-bit. It also omits the only correct statement a, which makes it inappropriate.
ここがポイント
- The 32-bit or 64-bit of a CPU is the width of data it can process at once (its register length); the number of address bits generally corresponds to it, and this decides the theoretical upper limit of the memory space that can be handled (about 4G bytes for 32-bit, and orders of magnitude larger for 64-bit).
- Note that a 64-bit CPU can run a 32-bit OS (they are compatible), and that the speed of peripherals such as USB is not determined by the CPU bit width.
用語