CS1252-OPERATING SYSTEM UNIT V1 Layered File System

CS1252-OPERATING SYSTEM UNIT V 1

Layered File System

CS1252-OPERATING SYSTEM UNIT V 2

A Typical File Control Block

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In-Memory File System Structures

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Schematic View of Virtual File System

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Contiguous Allocation of Disk Space

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File-Allocation Table

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Example of Indexed Allocation

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Indexed Allocation – Mapping (Cont.)

outer-index

index table file

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Combined Scheme: UNIX (4K bytes per block)

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Linked Free Space List on Disk

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FCFSIllustration shows total head movement of 640 cylinders.

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SSTF (Cont.)

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SCAN (Cont.)

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C-SCAN (Cont.)

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4.3 BSD Text-Segment Swap Map

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4.3 BSD Data-Segment Swap Map