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Compress memory area from PL/1 application program

 
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bauer
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Joined: 10 Oct 2003
Posts: 314
Topics: 48
Location: germany

PostPosted: Fri Apr 30, 2021 7:07 am    Post subject: Compress memory area from PL/1 application program Reply with quote

Dear *,

I have in PL/1 an memory block.

For example something like this:

Code:

DCL 1 MyStruct(100),
          2 NAME CHAR(20)
         ,2 ADDRESS CHAR(50)
         ,2 PHONENUMBER CHAR(20)
         ;


100 times some address records for example.

The address and current storage size is know of course of this memory block.

Now I like to compress this memory block.


Is there any function something like this:

Code:

CALL COMPRESSandCopy  (ADDR(MyStruct),CSTG(MyStruct), ADDR(DestionationArea), CSTG(DestinationArea))


or something like this:

Code:

CALL COMPRESS (ADDR(AnyMemoryArea), SIZE);



PL/1 builtin seems not to be available. Any zOS callable service?


Thank you,

bauer
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kolusu
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Joined: 26 Nov 2002
Posts: 12354
Topics: 75
Location: San Jose

PostPosted: Fri Apr 30, 2021 11:05 am    Post subject: Reply with quote

bauer,

I don't have an answer for your question, however I was wondering about the actual requirement. Looking at the structure you may have about 90-500 bytes of internal table and looking at the field names it seems that you can have variable length data.

Now assuming that there is a service to compress the data, how do you plan to decompress the data when you want to read it back? Doesn't the compress and decompress chew up an additional CPU ? Does this outweigh the storage allocation?
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bauer
Intermediate


Joined: 10 Oct 2003
Posts: 314
Topics: 48
Location: germany

PostPosted: Fri Apr 30, 2021 11:48 am    Post subject: Reply with quote

Hi Kolusu,

thank you for your reply.

Yes the sample for the requirement looks strange. The requirement is a little bit more complex, here reduced.

The question is more general according any available compression function in zOS / PL/1 as callable service or some thing other like that.

After reading the PL/1 manual, google search, search here in the forum, before posting the question, only third party products seems to be available for compression tasks in zOS in combination with PL/1.

So please no more efforts, we will try to find some other solution.

Bauer
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haatvedt
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Joined: 14 Nov 2003
Posts: 66
Topics: 0
Location: St Cloud, Minnesota USA

PostPosted: Thu May 06, 2021 10:58 pm    Post subject: Reply with quote

Bauer, are you attempting to reduce the size of the data in memory OR are you attempting to reduce the size of the data when stored on DASD.

If you are attempting to reduce the size on DASD, then refer to the sms acs routines. SMS compression can either be done by software or if a zEDC chip is installed, then it can be done with hardware compression off of the main CP's.
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bauer
Intermediate


Joined: 10 Oct 2003
Posts: 314
Topics: 48
Location: germany

PostPosted: Tue Aug 17, 2021 11:13 am    Post subject: Reply with quote

Well, I try to reduce the size of memory (ZIP) before for example sending the data .....,
thank you for asking.

But we have implemented a other solution now for the complete problem.
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