Memory in a computer system is access in either \"sequential accesses\" or \"ran
ID: 3869540 • Letter: M
Question
Memory in a computer system is access in either "sequential accesses" or "random accesses". Sequential accesses are the memory accesses that make memory access requests to consecutive addresses. For example, after the memory address X is accessed by the processor, some consecutive addresses, X+l, X+2, X+3, and X+4, while random accesses are the memory accesses that make non-contiguous addresses. Question: Is pipeline memory access effective in reducing memory access latency for sequential accesses and random accesses? Is memory-interleaving effective in reducing memory access latency for sequential accesses and random accesses? Answer the questions by completing the following table. Justify your solutions.Explanation / Answer
Comparing random versus sequential operations is one way of assessing application efficiency in terms of disk use. Accessing data sequentially is much faster than accessing it randomly because of the way in which the disk hardware works. The seek operation, which occurs when the disk head positions itself at the right disk cylinder to access data requested, takes more time than any other part of the I/O process. Because reading randomly involves a higher number of seek operations than does sequential reading, random reads deliver a lower rate of throughput. The same is true for random writing. You might find it useful to examine your workload to determine whether it accesses data randomly or sequentially. If you find disk access is predominantly random, you might want to pay particular attention to the activities being done and monitor for the emergence of a bottleneck.
For workloads of either random or sequential I/O, use drives with faster rotational speeds. For workloads that are predominantly random I/O, use a drive with faster seek time.
For workloads that have high I/O rates, consider using stripe sets because they add physical disks, increasing the system's ability to handle concurrent disk requests. Notice, however, that stripe sets enabled in software can cause an increase in consumption of the processor. Hardware-enabled RAID sets eliminate this impact on the processor but increase the consumption of processing cycles on the hardware RAID adapter.