Extent

Single Extents

  • Allocate files as sequence of contigious disk blocks -> single extent
  • Keep a free list of unused extents on disk
Pro Con
Easy sequential and random access, few seeks Horrible disk fragmentation, large files difficult to alloc
Simple Design Difficult to predict file needs at creation time

Multiple Extents

  • Table of base/size pairs (pointers)
Pro Con
Easy to find free extents Fuller disk -> lot of small extents -> many seeks
External Fragmentation
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Matthis Kruse
Masters Student

My research interests include programming languages and compilers.

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