rotational latency การใช้

• This operation, however, is often relatively inefficient ( see seek time, rotational latency ).
• To reduce the seek time and rotational latency, data are transferred to and from disks in large contiguous blocks.
• Traditional SSD benchmarks tend to focus on the performance characteristics that are poor with HDDs, such as rotational latency and seek time.
• Therefore, the rotational latency and resulting access time can be improved ( decreased ) by increasing the rotational speed of the disks.
• The drum's controller simply selected the proper head and waited for the data to appear under it as the drum turned ( rotational latency ).
• In fact, the leaves are chosen to be large enough that their access time is dominated by the bandwidth time, and therefore amortizes away the seek and rotational latency.
• An average hard disk drive has an average rotational latency of 3 ms, a seek time of 5 ms, and a transfer time of 0.05 ms / page.
• The new data blocks are necessarily scattered, slowing access due to seek time and rotational latency of the read / write head, and incurring additional overhead to manage additional locations.
• Average rotational latency is shown in the table on the right, based on the statistical relation that the average latency in milliseconds for such a drive is one-half the rotational period.
• Furthermore, sustained transfer rate tests do not give realistic throughput expectations for most workloads : They use I / O loads specifically designed to encounter almost no delays from seek time or rotational latency.
• "Rotational latency " ( sometimes called " rotational delay " or just " latency " ) is the delay waiting for the rotation of the disk to bring the required disk sector under the read-write head.
• Several tools and techniques that were implemented in the past to reduce the impact of the rotational latency of traditional HDDs, most notably disk defragmentation, SuperFetch, ReadyBoost, and application launch prefetching, involve reorganizing ( rewriting ) the data on the platters.
• For most magnetic media-based drives, the " average rotational latency " is typically based on the empirical relation that the average latency in milliseconds for such a drive is one-half the rotational period . " Maximum rotational latency " is the time it takes to do a full rotation excluding any spin-up time ( as the relevant part of the disk may have just passed the head when the request arrived ).
• For most magnetic media-based drives, the " average rotational latency " is typically based on the empirical relation that the average latency in milliseconds for such a drive is one-half the rotational period . " Maximum rotational latency " is the time it takes to do a full rotation excluding any spin-up time ( as the relevant part of the disk may have just passed the head when the request arrived ).