問90
頻出度★☆☆
CPUのクロックに関する説明のうち, 適切なものはどれか。
令和3年度 ITパスポート試験 問90
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 90
Incorrectア
The data transfer rate between a USB-connected peripheral device and the CPU is determined by the transfer mode and signal-line speed defined by the USB standard (such as USB 2.0 or USB 3.0), not directly by the CPU clock frequency. The clock frequency and the USB transfer rate are different things.
Incorrectイ
The description is reversed. The shorter the clock interval (period), the higher the number of clocks per second, i.e., the clock frequency, so each operation is beaten out faster and the time required to execute an instruction becomes shorter. Saying it takes longer is wrong.
Incorrectウ
Recording and holding the location (address) where the next instruction to be executed is stored is the role of the program counter (instruction address register), not the role of the clock. The clock does not record location information.
- エ
正解 A clock is a regular pulse signal generated by the CPU so that the CPU and its peripheral circuits operate in step at a fixed period (beat). Each circuit acts on the rising and falling edges of the clock as its cue, so the clock plays the role of a conductor that coordinates the timing of a series of operations such as fetching an instruction, decoding it, and executing it. Choice エ correctly states the clock’s essential role of adjusting the timing of instruction execution, so it is appropriate. The number of clocks per second is the clock frequency (in Hz); generally, the higher the frequency, the faster the processing.
ここがポイント
- The clock is a regular pulse signal generated by the CPU, and its role is to synchronize and adjust the operation timing of each circuit.
- The number of clocks per second is the clock frequency (Hz); the higher the frequency (i.e., the shorter the clock interval), the faster the processing. The one that holds the storage location of the next instruction is the program counter.
用語