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      STACKER NOTE                                         STACKER NOTE
                     "Lost Sector Groups" and Stacker             
      STAC FAX  3501 (08-22-1994)
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      Background
      
      The Stacker CHECK utility sometimes may report lost sector groups. 
      This sounds ominous, but it's harmless and does not mean that any 
      data has been lost or corrupted.
      
      A lost sector group comes into existence on a Stacker drive when 
      datahas been written to a cluster but the cluster hasn't been 
      allocated to a file. The sectors belonging to the cluster can't 
      be reused because the cluster could be allocated to a file at any 
      time. The lost sector group automatically goes away as soon as 
      the operating system does allocate the cluster to a file. A lost 
      sector group that persists long enough to be reported by Check 
      is usually the result of a file being extended and then 
      truncated without the operating system updating the FAT in between.

      
      Result
      
      Do not use the /=D switch with CHECK. This switch is intended for
      internal development purposes only. Lost sector groups are not a
      problem.Running CHECK /F does not report or deal with lost sector
      groups unless they take up more than 6% of the drive; in that case, 
      it clears  the  condition.Running CHECK /=D /F reports all lost 
      sector groups and offers to delete the areas. Do not let  it  do 
      this; respond NO if  CHECK offers to delete any area. If you want 
      to clear out lost sector groups for some reason, run SDEFRAG  
      or choose Stacker  Optimizer from the Stacker Toolbox  (STAC).  
      Any choice (Full  Optimize, Quick Optimize, or  Restack)  
      completely clears lost sector groups.
      
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      Copyright 1994 Stac Electronics
