HP OpenVMS Systems

RMS file positioning (placement)?

» close window

The Question is:

 
What and How are 'placed files' created?
Is there a way to change the 'placed' attribute
to what maybe considered 'normal'?  I only have
2 files on 3 disks of this category and don't
have a clue how they got this way.
 
Thanks,
 
 

The Answer is :

 
  One can explicitly "place" files through FDL commands, via RMS XABALL
  attributes, or directly through ACP QIO calls -- this indicates that
  the file should be located in a particular area (track, sector, cylinder)
  of the disk.  (Also note that many disks will synthesize the track,
  sector, and cylinder values reported to the host -- on many modern disk
  drives, the traditional disk geometry information reports can be largely
  or entirely meaningless, only the maximum LBN (total disk size; number
  of blocks present) is certain to have meaning.)
 
  The easiest way to "place" a via is through the use of EDIT/FDL ...
  ADD AREA 0 ... POSITION ...  The FDL output might look like:
 
    	AREA 0
    		ALLOCATION	1
                POSITION    file_name   "sys$login:login.com"
 
  You can implicitly (unknowingly) place file extents through RMS.  When
  RMS needs to increase the size of an indexed file, it will request the
  XQP to try to put the next extent close to the last one.  If the XQP
  manages to do so, then it will mark the file as "placed".  Normally,
  this is a benign attribute, but it has been known to confuse various
  file defragmentation tools.  (If anything, this indicates the file
  should have an increased file allocation the next time it is created.)
  Of course, if a file was deliberatly placed, one should try to honor
  that for any subsequent file recreations or relocations.
 

  

     

     
answer written or last revised on ( 7-OCT-1999 )
     
» close window