Occasionally, a customer may have severe problems with z/XDC, and he may want to revert to an older level of z/XDC. However, due to the design of z/XDC’s installation process, it is not possible to revert to an older level without either reIPL’ing or somehow clobbering z/XDC’s SSCT entry to make it not findable by z/XDC.
Typically, the easiest way to zap an SSCT on your running System was to use z/XDC to find it and zap it. But if z/XDC is not working correctly… Well, you can see the problem here.
To meet that need, we’ve written a standalone utility named XDCREMOV. Running it is simple. The JCL is:
- //RESET EXEC PGM=XDCREMOV,PARM=XDC
What it does is, it finds z/XDC’s SSCT and changes the 4th character of its SSCTNAME field to a blank. This has the following effects:
- For the currently installed System Interface, all of its elements become instantly disabled. This is because they have been coded:
- To know where the SSCT is,
- To know what the SSCT’s name should be,
- To always check to see if the name has changed,
- And to functionally NOP if the name has changed.
- So changing the name of the SSCT completely turns off the existing System Interface.
- Then the next time z/XDC is started authorized:
- It will search for a previously installed System Interface and not be able to find it.
- So it will install a new System Interface.
- Since z/XDC cannot find its older SSCT, a level comparison cannot be done.
- So a backlevel XDC will now install successfully.
In other words, once XDCREMOV has be run, you can now start up a backlevel of z/XDC with no problems.
To effectively remove z/XDC from your System, use the following process:
- Bring down z/XDC’s Server Task: C XDCSRVER
- Start a job that runs XDCREMOV authorized.
- Install the back level of z/XDC that you want to revert to.
- Restart the Server task: S XDCSRVER
Since XDCSRVER runs authorized, the replacement System Interface will be installed.
The XDCREMOV utility was added by update CBC-1809D. The starting point for more information is HELP WHATSNEW Z22 THINGSFIXED MAINTENANCE.