On Tue, Feb 20, 2018 at 1:08 PM, Ron hawkins <[email protected]>
wrote:
> John,
>
> Have you thought about how to signal updates to pages in the LDS to other
> jobs and LPARs?
>
I write selfish programs. So they don't worry about sharing! {grin}
I am going to be looking at this for a "port" of SQLite to z/OS which will
implement a permanent "memory" data base VFS (Virtual File System) by using
an LDS mapped into a data space. Of course, SQLite is written in C and
regular C does not support AR mode. {sigh}. I have a port which uses UNIX
files to store the data base, but a number of people we disappointed that I
was using UNIX and wanted to use "normal" data sets. SQLite is meant to be
"embedded" and assumes NO sharing of the database between processes
(address spaces).
>
> Hiperbatch is a great way to accomplish what you are trying to do, but
> there is exposure if you share the data set.
>
> Ron
>
> -----Original Message-----
> From: IBM Mainframe Discussion List [mailto:[email protected]] On
> Behalf Of Allan Staller
> Sent: Tuesday, February 20, 2018 8:13 AM
> To: [email protected]
> Subject: Re: [IBM-MAIN] Any way -- DIV map LDS into data space?
>
> Look up HIPERBATCH (been around since MVS/ESA). It is pretty much exactly
> what you are looking for.
>
> -----Original Message-----
> From: IBM Mainframe Discussion List [mailto:[email protected]] On
> Behalf Of John McKown
> Sent: Tuesday, February 20, 2018 9:55 AM
> To: [email protected]
> Subject: Any way -- DIV map LDS into data space?
>
> I know that it is possible to use DIV (Data In Virtual) to "map" an LDS
> into an address space. And then use "windowing services" to move the
> "window" around within the LDS.
>
> What I would really like to do is have an LDS. And, somehow, have an API
> which would take this LDS and create a data space for me which simply
> "maps" the entire LDS into the data space. Basically making the LDS a
> "private page dataset". I would also like to have a way to "harden" all the
> changed pages in the data space into the LDS (e.g. force pageout changed).
> And, of course, it would write all the changed pages (and delete the data
> space) when I request that the LDS be "closed".
>
> I just don't see a way to do this. Not even in the 2.3 books. But I'm
> hoping that I missing something. And, if you're interested, this
> idea/desire was triggered by the UNIX "mmap()" type functions which map a
> regular UNIX file as a range of memory.
>
> Seems to me that IBM has basically "functionally stabilised" DIV. Like an
> idea that just didn't pan out.
>
> --
> I have a theory that it's impossible to prove anything, but I can't prove
> it.
>
> Maranatha! <><
> John McKown
>
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--
I have a theory that it's impossible to prove anything, but I can't prove
it.
Maranatha! <><
John McKown
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