Difference between revisions of "Ploop/format"

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A ploop image file format is pretty simple.
 
A ploop image file format is pretty simple.
  
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* Image consists of cluster blocks (default cluster block size is 1 MB).
 
* Image consists of cluster blocks (default cluster block size is 1 MB).
 
* First there are some cluster blocks with BAT (Block Allocation Table), then there are some cluster blocks with data.
 
* First there are some cluster blocks with BAT (Block Allocation Table), then there are some cluster blocks with data.
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* If a slot N contains value M, then a request to a cluster-block N of a /dev/ploopXXX device is redirected to a cluster-block M in an image file. N is counted from 0, while M is counted from 1 (0 means block is not yet allocated).
 
* If a slot N contains value M, then a request to a cluster-block N of a /dev/ploopXXX device is redirected to a cluster-block M in an image file. N is counted from 0, while M is counted from 1 (0 means block is not yet allocated).
  
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For the rest of the story, see sources.
 
For the rest of the story, see sources.
 
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[[Category: Storage]]
 
[[Category: Storage]]

Latest revision as of 22:26, 25 December 2015

<translate> A ploop image file format is pretty simple.

  • Image consists of cluster blocks (default cluster block size is 1 MB).
  • First there are some cluster blocks with BAT (Block Allocation Table), then there are some cluster blocks with data.
  • First 64 bytes of the first cluster block is a header, described in ploop1_image.h
  • The rest of BAT is just an array of 4 byte slots.
  • If a slot N contains value M, then a request to a cluster-block N of a /dev/ploopXXX device is redirected to a cluster-block M in an image file. N is counted from 0, while M is counted from 1 (0 means block is not yet allocated).

For the rest of the story, see sources. </translate>