Written by Dave Gomberg Nov 15, 2011

OK, the problem began when Charlie Whitman and I were waiting in the lobby
of a hotel which was the locus of an interim SHARE, about 15 months before
the button appeared.  The hotel was in the southeast, if you have a list of
old SHARE venues.  Charlie mentioned that many
3083 users of SAS (where he worked) had very high T/V (total/virtual CPU
time) ratios when running SAS.  I said that 3083s were famous for having
very poor VM simulation of priv ops resulting in high T/V ratios and I would
look more at the problem when I got home.

I sat down at a terminal and set SPOOL PRINT START TO * and TRACE PRIV PRINT
and ran the SAS installation test, then closed the virtual printer.  A spool
file of several hundred thousand lines appeared in
my virtual reader.   In a minute or so, I had found the location of
an SSK (set storage key) instruction that was responsible for almost
all the privs in the trace.   I no-oped the instruction in my nucleus
and reran the test.  The T/V ratio was quite normal (low) and the
test completed much more quickly.   I called Charlie with the info,
in a couple of hours he called me back and said that CMS did a lot of key
management on GETMAIN and FREEMAIN macro simulation.  We discussed it and
concluded that the key management was
unnecessary.   Charlie wrote a source update to eliminate the SSK
instruction from the CMS nucleus, and we both started testing it.

No ill effects were found, so we opened a performance APAR with IBM,
assigned number VM14999.   It was shortly closed WAD (working as
designed).   Meanwhile my installation (which did not even have a
308x processor) and Charlie's and many dozens of others started
running the deletion code as a mod to their systems.   When I
challenged IBM about their closure of the problem, they said that CMS was
designed that way, even tho the simulation did NOT match the
behavior of real hardware.   When I asked if every installation were
running the mod, would IBM then incorporate it into the product, the IBMer
assigned to the CMS Project said NEVER.

It then became an us vs. them issue, and was a major plank in the anti-OCO
movement.