ITPEC IP April 2023 Question 23
If data is repeatedly added to and deleted from a hard disk on a PC, data may not be stored in consecutive areas on the hard disk. When no measures are taken, which of the following can most likely occur?
Explanation
Stored data is not read quickly — fragmentation scatters a file across the disk and slows reading.
When files are written and deleted again and again, the free space breaks into small gaps, and a new or growing file is split over several non-consecutive areas (fragmentation). The file system records where every piece is, so the data is still written and read correctly. But on a hard disk the head must seek from piece to piece, so reading a file takes longer. Defragmentation rearranges the pieces into consecutive areas and restores the speed.
Answer (d)
Why not others:
- •(a) — where a file's blocks lie on the disk has no effect on whether antivirus software detects a virus
- •(b) — the file system writes into scattered free areas and keeps track of them, so writes are still correct
- •(c) — the pieces are read back in the recorded order, so the data is correct, only slower to fetch
Key rule: Fragmentation costs speed, not correctness; defragmentation is the remedy, and it matters for hard disks with moving heads rather than SSDs.
Software · AI-written, may contain errors
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