File system fragmentation: Difference between revisions

Revision as of 23:47, 30 April 2023

Revision as of 02:15, 6 August 2023

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{{Essay-like|section|date=June 2019}}

Some early file systems were unable to fragment files. One such example was the [[Acorn Computers|Acorn]] [[Disc Filing System|Acorn DFS]] file system used on the [[BBC Micro]]. Due to its inability to fragment files, the error message ''can't extend'' would at times appear, and the user would often be unable to save a file even if the disk had adequate space for it.

DFS used a very simple disk structure and [[Computer file|files]] on [[Hard disk|disk]] were located only by their length and starting sector. This meant that all files had to exist as a continuous block of sectors and fragmentation was not possible. Using the example in the table above, the attempt to expand file F in step five would have failed on such a system with the ''can't extend'' error message. Regardless of how much free space might remain on the disk in total, it was not available to extend the data file.