  OpenVMS System Tuning? (QUANTUM) 
 The Question is:
 
Is the scheduler, e.g. the usage of quantum/iota significantly changed in
 AXP/VMS V7.2 compared to VAX/VMS 6.2....?
It can be demonstrated, that the dynamics of OpenVMS are completely different
 from
the "old times". If there is only ONE compute bound job (prio=4) without any
 i/o or
paging on the system (DS10), then the behavior of the system is extreme
 sluggish, e.g. mc sysgen show quantum does take 40 seconds in a second
 decterm? (quantum is 10, iota=1).
I did encounter the same kind of problems on axp 4100 multiple cpu mashines,
 but never had a chance, to track the user (stock traders) complaints in any
 way, so we had been having this kind of non-traceble problem for more than 2
 years, most of the time,
the extra cpu's on the 4100's did circumvent the problem.
 
 The Answer is:
 
  It can be demonstrated that OpenVMS has changed significantly from
  "old times" in a variety of ways.  Old rules-of-thumb and older
  tuning techniques may or may not be applicable to newer OpenVMS
  releases and/or to particular OpenVMS VAX or OpenVMS Alpha systems.
 
  As for one discussion of a change related to the processing around
  QUANTUM, please see topic 4341 here in Ask The Wizard.
 
  The value of IOTA defaults to 2, and changes to it generally also
  involve a (recommended) discussion with Compaq Customer Services.
 
  Without significantly more information on the system configuration
  (hardware, software, settings, etc), the OpenVMS Wizard is not in a
  position to assist with tuning and site- and configuration-specific
  issues.  Please contact the Compaq Customer Support Center directly
  for assistance in tuning the system, and for assistance meeting the
  particular system responsiveness requirements.
 
