HP OpenVMS Systems

OpenVMS Memory Management Details?

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The Question is:

 
Dear Sir
I have a COMPAQ AlphaServer DS20E 500 MHz with 1 GB memory. I have questions as
follows
1. When I use $CRMPSC system sevice to creare share global section , how it
 effects to physical memory. If I allocate
  2 MB sharable global will the  physical memory be reduced by 2 MB ?
2. Where VMS allocate share global section memory to ?
3. Will global section be in physical memory ?
4. What is the relation between GBLPAGES ( sysgen ) and physical memory ?
5. How does VMS handle physical memory and page file ? When user application
 request for memory where VMS give memory to first , page file or physical
 memory.
6. Will total working set size of all running
processes equal to in used memory ( from show memory command ) minus by VMS
 used memory ?
 
Regards
 
Wichaya Charnlertlakha
 
 
 

The Answer is :

 
  You will want to review the Internals and Data Structures Manual for
  details of paging and swapping, of physical and virtual memory
  management, of global section internals, and various related topics.
 
  1: Indeterminate, though aggregate physical memory usage will probably
     increase somewhat based simply on increased virtual memory usage.
 
  2: Please see the documentation of the SEC$x_EXPREG flag.
 
  3: Indeterminate, and dependent on system paging activity, available
     physical memory, and references to the specified virtual memory.
 
  4: In SYSGEN, HELP SYS_PARAMETERS GBLPAGES
 
  5: Please see the Internals and Data Structures Manual.
 
  6: No.
 

  

     

     
answer written or last revised on ( 7-FEB-2001 )
     
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