Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!apple!sun-barr!newstop!sun!quintus!jbeard
From: jbeard@quintus.UUCP (Jeff Beard)
Newsgroups: comp.protocols.ibm
Subject: Re: Problem with JES2 proclibs
Message-ID: <1231@quintus.UUCP>
Date: 31 Jul 89 15:51:14 GMT
References: <8907310402.AA11042@jade.berkeley.edu>
Reply-To: jbeard@quintus.UUCP (Jeff Beard)
Organization: Quintus Computer Systems, Inc: Mountain View, Ca
Lines: 12

>If SPACE is on the DD, the secondary allocation in the DSCB is ignored, 
>regardless of whether it's 0

I'm not sure of this with current levels of JES/ MVS, however, back with MVS/SP
an prior systems, DSCB with zero secondary space can NEVER be extended.
Original DD allocations like SPACE=(Quantum,(Pri,Sec,1)), allow subsequent JCL
overrides of SPACE=(Quantum,(Pri,Sec,NN)), while DSCBs with secondarys of zero
will ignore the JCL override attempt.

I concur that the symptoms match that of a new extent being taken when updated,
and not seen when referenced.  This is a behavior that reflects the underpinning
OS/360 PCP/MFT/MVT origins of the system.