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when is it used? ADDRSPC=REAL

 
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icemanster

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Joined: 30 Jan 2009
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PostPosted: Wed Feb 25, 2009 10:10 pm    Post subject: when is it used? ADDRSPC=REAL
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Hi i would just like to ask when do we use ADDRSPC=REAL

i saw this from the net:
ADDRSPC: this parameter specifies whether your job should use the Virtual memory or the Real memory when executing.

Advantage of Virtual memory is , the Job can be paged. Virtual is Default.

Region:- Region parameter allocates the specified memory in the Real storage or Virtual storage as mentioned in the ADDRSPC parameter.

If they are coded in the EXEC statement , then they are applicable only for that step.

If coded both on job and exec then Job overrides Exec.


===

here is my question..
1. what is paged?
2. what happens when REAL is used? I believe real means central storage.. what is central storage?

I hope you could help me with this one.. Thank you very much!
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Robert Sample

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Joined: 06 Jun 2008
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Location: East Dubuque, Illinois, USA

PostPosted: Wed Feb 25, 2009 10:26 pm    Post subject:
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1. Memory is paged (if needed). This means if another job needs more memory, and your job can be paged, your memory can be written to auxiliary storage and the memory pages taken over by the other job. This is basic virtual systems -- if you're running on an IBM mainframe and don't know this you could have lots of future problems.
2. REAL means non-pageable memory is used -- which is typically reserved for use by the operating system, pretty much never is needed by applications programmers, and also tends to be quite limited. Started tasks, utilities, and operating system components typically are the only programs using REAL memory.
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Anuj Dhawan

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PostPosted: Wed Feb 25, 2009 11:02 pm    Post subject:
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You might compare these concepts with "RAM" & "ROM". Real memory refers to the actual memory chips that are installed in the computer. All programs actually run in this physical memory. However, it is often useful to allow the computer to think that it has memory that isn't actually there, in order to permit the use of programs that are larger than will physically fit in memory, or to allow multitasking (multiple programs running at once). This concept is called virtual memory.
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Anuj Dhawan

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PostPosted: Wed Feb 25, 2009 11:07 pm    Post subject:
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You might like to check this link: http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.prftungd/doc/prftungd/real_memory_mngment.htm
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icemanster

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PostPosted: Thu Feb 26, 2009 12:45 am    Post subject: Reply to: when is it used? ADDRSPC=REAL
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Thanks for the much needed info guys!
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Anuj Dhawan

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PostPosted: Thu Feb 26, 2009 5:45 pm    Post subject:
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Glad to help you...icon_smile.gif
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