----------------------<snip>------------------------------
At my customer's site there are some user-written MVS subsystems,
written in the 80s and 90s. They seem to be very important and are in
production use every day. Now I was asked to take responsibility for
them, because the guy who wrote them will be retired soon.
I started examining the code and observed that he doesn't use the
services described in the books like "Using the Subsystem Interfaces",
Chapter 4, "Writing Your Own Subsystem", but instead he inserted the
control blocks like SSCT and SSVT using GETMAIN and CS (taking care of
parallel writers) and moved the function code into the CSA using MVCL
etc. - all fine code, but no IEFSSI and other macros anywhere.
Maybe the services didn't exist yet when the original code was written?
------------------------------<unsnip>----------------------------
It's quite possible that the services didn't exist, but I'm sure that
perhaps a few were available. The "Grey Cells" are getting old, so I'm
not really sure.
-------------------------------<snip>------------------------------
What do you think of this, is it ok to do it this way? Are there any
drawbacks? Do you have any hints in general? Would you consider to
rewrite significant parts of these subsystems to use the (new?)
services? I don't think that we have the resources to do so at the moment.
-----------------------------------<unsnip>-----------------------------------
I HATE these kinds of situations, because there's really no "nice"
answer. If your production environment demands these subsystems, I'd be
inclined to try to rewrite and debug the appropriate sections of code to
use the defined mechanisms and available services. This might not be
entirely feasable but consider this: what if those interfaces change in
a subsequent release of z/OS?? If you're using the currently-defined
mechanisms, the transition(s) MIGHT be a great deal less painful,
perhaps as simple as a re-assembly to use the updated macros. Perhaps a
re-arrangement of priorities is in order? YMMV.
Rick
--
If you're not the lead dog, the view never changes.
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