12_Storage classroom slides

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12_Storage classroom slides
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Name to disk block mapping
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Free list
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Cyl, surf, track, sector
File name disk address
Free list of disk blocks
/foo start addr /bar start
addr .
Name table
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Linked List Allocation
Free list of sectors?
File name disk address
/foo 30
/bar 50
Name table
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Linked allocation
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File allocation table
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Indexed allocation
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Multilevel indexed allocation
Data blocks
Directory
100
i-node for /foo
1st level
30
40
100
File name i-node address
40
201
45
201

/foo 30
45
299
299
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Hybrid indexed allocation
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i-node structure in Unix
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i-node for /users/faculty/rama/foo
i-node for /users/faculty/rama
Refcount 1
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Type directory
Type data file
File name
i-node address
direct (100)
30
direct (201)
foo 30
single indirect (40)


double indirect (45)
triple indirect

Reference count on files
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i-node for /users/faculty/rama/foo /users/faculty
/rama/bar
i-node for /users/faculty/rama
Refcount 2
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Type directory
Type data file
File name
i-node address
direct (100)
30
direct (201)
foo 30
single indirect (40)


double indirect (45)
bar 30
triple indirect

Hard links
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Sym links
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After deleting foo and bar
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Layers of the file system