Secondary memory

Secondary

To reduce the seek time and rotational latency, secondary storage, including HDD, ODD and SSD, are transferred to and from disks in large contiguous blocks. Secondary storage is addressable by block; once the disk read-and-write head on HDDs reaches the proper placement and the data, subsequent data on the track are very fast to access. Another way to reduce the I/O bottleneck is to use multiple disks in parallel to increase the bandwidth between primary and secondary memory, for example, using RAID.