G88 and G90 startup time on IBM mainframes



 G88 and G90 begin their execution by initializing a large direct-access
 file (the RWF file) that is used to hold many logical files over the
 course of the run.  The RWF initialization takes little CPU time, but it
 takes from 20 to 30 minutes wall-clock time in VM/ESA CMS release 8 on
 the IBM 3090-300J at this site.  This is a terrible burden, and makes
 running more than a small sample of the test jobs shipped with the
 installation package a painful chore.  I have attempted to get G90 to
 run with an RWF file created and initialized by a different program, but
 I have failed in my various attempts with STOP 300 or STOP 400 errors.
 Does anyone know a way to get G90 to accept an RWF file that has been
 created outside G90?  If affirmative, does anyone have handy a program
 to quickly generate the RWF file?  Or, has anyone modified G90 to
 expedite the creation of the RWF file?  Even in multihour batch G90
 jobs, this 30 minute initialization represents considerable lost
 opportunity to do useful work.  (I am aware that the G90 user can
 specify a smaller RWF file size, but this feature is rarely used at this
 site, since the initialization time is almost invisible to batch G90
 users.)
            - Alan Hinds  U32472 ( ( at ) ) UICVM.UIC.EDU