Memory segmentation: Difference between revisions

Revision as of 01:48, 9 July 2020

Revision as of 01:52, 9 July 2020

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In this case each segment has an associated flag indicating whether it is present in main memory or not. If a segment is accessed that is not present in main memory, an exception is raised, and the [[operating system]] will read the segment into memory from secondary storage.

Segmentation is one method of implementing [[memory protection]].<ref name="ostep-1">{{citationcite book|title=Operating Systems: Three Easy Pieces [Chapter: |chapter=Segmentation]|chapter-url=http://pages.cs.wisc.edu/~remzi/OSTEP/vm-segmentation.pdf|publisher= Arpaci-Dusseau Books|year = 2014|first1 = Remzi H.|last1 =Arpaci-Dusseau|first2=Andrea C.|last2 = Arpaci-Dusseau}}</ref> [[Page (computer memory)|Paging]]<!-- please, do not "simplify" or "fix" the link. The [[paging]] article is about a virtual memory technique, not about memory protection --> is another, and they can be combined. The size of a memory segment is generally not fixed and may be as small as a single [[byte]].<ref>{{cite book|publisher=Intel Corporation|title=Intel® 64 and IA-32 Architectures Software Developer’s Manual Volume 3 (3A, 3B & 3C): System Programming Guide|year=2012|pages=3–13|url=http://download.intel.com/products/processor/manual/325384.pdf}}</ref>

Segmentation has been implemented in several different ways on different hardware, with or without paging. Intel [[x86 memory segmentation]] does not fit either model and is discussed separately below, and also in greater detail in a separate article.