The following message is a courtesy copy of an article
that has been posted to bit.listserv.ibm-main,alt.folklore.computers as well.
[EMAIL PROTECTED] (Bob Shannon) writes:
> Sure. The thousands of in-stream usermods that were written prior to
> XA, and which greatly inhibited subsequent upgrades. I certainly agree
> that in the early days usermods were written to overcome functional
> deficiencies in MVS. Some, such as logical swap, were incorporated
> into MVS. Others, such as the dual master catalog mod at a large US
> insurance company, proved to be a nightmare to maintain and an even
> worse nightmare to remove.
cp67 and vm370 were notorious for user modifications ... in part because
it shipped not only with full source ... but its whole customer
maintenance infrastructure was source based (i.e. each fix shipped as
incremental source update file).
in the early 80s there was a study of local vm370 system modifications.
internal corporate "local" modifications were as large as the base
system ... and the "share" library source changes were approximately
equivalent to the internal corporate "local" modifications (in size and
part of all this started with unbundling announcement 23jun69
starting to charge for application software. however, the case was made
that kernel code could still be "free" (bundled).
A lot of the structural and functional enhancements that I had done to
cp67 as an undergraduate (and was picked up and shipped in the product)
was dropped in the morph from cp67 to vm370. However, I had
done the port myself ... referenced in this prior post
http://www.garlic.com/~lynn/2007t.html#69 T3 Sues IBM TO Break its Mainframe
and this old email
I distributed and supported the "CSC/VM" system (mentioned in the above)
for a large number of internal datacenters. The product picked up some
small pieces of the above as part of VM370 rel3.
However, other pieces were selected to be released as separate "resource
manager" product ... and also got chosen to be guinea pig for
unbundling/charging for kernel software (which met that i had to spend a
lot of time with business people ironing about the policies for kernel
because of the extensive source oriented culture ... most customers
managed to regularly track local source code changes as new releases
However, I know of (at least) one notable exception. Somehow or another,
a very early "CSC/VM" system was leaked to AT&T longlines. Over a period
of years, they developed a large body of their own source changes
... never bothered to track releases, and migrated it to a number of
their own machines. Nearly a decade later, I was tracked down by the
AT&T national marketing rep about trying to help get AT&T longlines off
this ancient CSC/VM system.
The "OCO-wars" (object code only) in the early 80s were somewhat
There had been some number of commercial online timesharing services
formed from cp67 and vm370.
these were somewhat similar to the internal HONE systems that worldwide
sales and marketing used
One of these was Tymshare which in the mid-70s started providing the
vmshare online discussion forum to share members. That vmshare forum has
now been archived here
included in the forum archives are the OCO-war discussions from the
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