This was the way things were done back in the days when IBM published things like debugging handbooks and logic manuals. I still have a copy of "MVS Interface Facilities, a student text rescued from a trash bin, and dating from the days when writing this sort of home grown software was considered acceptable behavior.
If this sort of thing is still in production your customer needs his head examining. If I was made "responsible" for this something like this I would start by examining exactly what services are provided by the subsystem and then see how they could be replaced. Many of the reasons for user code of this kind have been made redundant by standard IBM MVS/JES services or by other software vendors' products. Once you get past the emotional attachment to the code a supported replacement could probably be found. David Elliot zSeries Software Support -----Original Message----- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Bernd Oppolzer Sent: Monday, November 16, 2009 11:41 AM To: IBM-MAIN@bama.ua.edu Subject: user-written MVS subsystems Dear listers, 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? 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. Kind regards Bernd ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
