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Editor: yakko
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Revision 2 as of 2004-03-31 17:47:00
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Editor: yakko
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Deletions are marked like this. Additions are marked like this.
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   n = LBS/SFS <= 8.    n = LBS:SFS <= 8:1.
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Suppose that LBS=8K and SFS=2K. Given a file of 18,000 bytes we would allocate
{{{
2 8K blocks + 1 2K block = 16384 + 2048
                         = 18,432 bytes.
}}}

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Terms:

  • data blocks
  • block sizes max ratio 8:1
  • Allocation Example
  • fragment recopying problem
  • inodes
  • direct blocks and indirect blocks, single, double and triple indirection
  • directories, hard links and symbolic links
  • mapping a file descriptor to an inode

See Also DiskStructures

Data Blocks

Data blocks contain whatever the user put into them. There are two sizes in Free BSD, one large block size (LBS) and smaller fragment size (SFS).

   LBS = n x SFS 
   LBS > SFS
   n   = LBS:SFS <= 8:1.

Suppose that LBS=8K and SFS=2K. Given a file of 18,000 bytes we would allocate

2 8K blocks + 1 2K block = 16384 + 2048 
                         = 18,432 bytes.

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FileSystem (last edited 2004-03-31 19:19:36 by yakko)