rotational latency

Data transfer times are typically fractions of a millisecond , so rotational latency and seek time are the primary sources of disk latency on a physical HDD .

数据传输时间一般几毫秒，所以旋转延迟时间和寻道时间是一个物理HDD的主要磁盘延迟时间来源。

The time it takes to complete an I / O request ( referred to as disk latency ) is a combination of seek time , rotational latency , and disk transfer time .

而完成一次I/O请求（称为磁盘延迟时间）所需要的时间是寻道时间、旋转延迟时间和磁盘传输时间之和。

The average rotational latency is one-half of a revolution of the disk platter .

平均旋转等待时间指的是磁盘旋转一半的时间。

The reason is that HDD performance is limited by mechanical constraints such as head movement ( seek time ) and rotational latency .

这是因为HDD的性能受到诸如磁头移动（寻道时间）和旋转等待时间等机械约束的限制。

Because EFDs have no moving parts , they are not constrained by seek time or rotational latency in the way that FC and SATA HDDs are .

因为EFD没有移动的部件，所以它们不会像FC和SATAHDD那样受到寻道时间或旋转延迟时间的约束。