(a) Explain how defragmentation software improves the performance of a magnetic hard disk drive. [3]
(b) Explain why defragmentation is not needed on a solid state drive. [1]
- (a) Over time files are split up / fragmented and stored in non-contiguous blocks across the disk(1)
- (a) Defragmentation moves / reorganises the parts of each file so they are stored next to each other (contiguously), and groups free space together(1)
- (a) So the read/write head moves less, so files are accessed / read faster(1)
- (b) An SSD has no moving parts / no read/write head, so the location of data does not affect access time; allow: it would reduce the SSD's lifespan due to extra writes(1)
- Answer: (a) Fragmented files are rearranged into contiguous blocks so the read/write head moves less → faster access (b) SSD has no moving parts, so location doesn't affect speed
- Examiner tip: The performance gain comes from the read/write head moving less – make that link explicitly to get the third mark.