Comment # 3 on bug 1209162 from Stefan Hundhammer

Knut, please have a look.

Ancor couldn't really do actual testing, he came to those conclusions from
reading the source code.

I also read it, and I was a bit overwhelmed by the complexity of setting such a
simple flag. Please also check out the small issues that I found; maybe they
are important, maybe they are not.

If you test that DIAG and find that it works as expected, so much the better.
But somebody who knows his way around s/390 DASDs should really give this a
try.