On Sun, Dec 3, 2017 at 10:39 PM, David Crayford <[email protected]> wrote:

> You don't need to be authorized to use z/OS UNIX shared memory segments.
> You do need access to the file system and the memory segments are protected
> using the normal UNIX permissions. Semaphores and pthread mutexes can also
> reside in shared memory for inter-process locking.
>
> The /tmp TFS is backed by memory so the easiest solution may be to us
> files in the TFS.
>
>
​The only problem that I have ever had with using /tmp is that, if it were
"released" (i.e. documented to & it's use encouraged) to programmers, then
I would run into complaints about "running out" of space on /tmp and file
name collisions. E.g. one job using up all the space in /tmp due to the JCL
writing believing it would just be a few records, but then a "bug" cause it
to try to write millions (this has happened here). ​Also, our programmers
at least, tend to be "lazy" and expect z/OS to "clean up" after them (some
of them don't even CLOSE their data sets). So I would need to manage the
files & directories in /tmp, most likely using skulker. And, of course,
that means that eventually somebody will whine that one of their files got
deleted.

​I have addressed a _UNIX shell user_ using too much "temp" space by making
/tmp2 be an "automount controlled" mount point and forcing all the
"temporary file location" environment variables, such as TMP, TMPDIR, TEMP,
et al., to be /tmp2/&SYSUID. So when a shell user uses a properly coded
shell command, they go into their own zFS filesystem data set.​


-- 
I have a theory that it's impossible to prove anything, but I can't prove
it.

Maranatha! <><
John McKown

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