A disk drive creates and saves a file by laying it in contiguous clusters on the disk drive. When that file is later read, the head in the disk drive moves directly from one cluster to another on a single track. The head stays in one place over that track and reads the file as the disk moves beneath it. As more files are written to the disk, they are also laid out in contiguous clusters.
A disk drive creates and saves a file by laying it in contiguous clusters
on the disk drive. When that file is later read, the head in the disk drive
moves directly from one cluster to another on a single track. The head stays
in one place over that track and reads the file as the disk moves beneath
it. As more files are written to the disk, they are also laid out in contiguous
clusters.
When files are erased, their clusters are made available again as free
space. Eventually, some newly created files become larger than the remaining
contiguous free space, and those files are broken up and randomly placed
throughout the disk. As the file creation, editing and deleting process
continues, fragmentation becomes pronounced, exacting a progressively heavy
toll on system performance.
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