  Disabling DCache on Alpha System? 
 The Question is:
 
How do I disable to d-cache on an OpenVMS Alpha System ?
 
 The Answer is :
 
  You have not indicated why you wish to disable the Data Cache (DCache)
  on your particular Alpha system.
 
  The DCache is used to provide faster access to data, by reducing the
  frequency of main system memory references.  There are typically two
  cache levels on an Alpha microprocessor, the primary or on-chip cache
  (PCache) and the backup or off-chip cache (BCache).  The on-chip PCache
  is both fast and local to the processor.  The off-chip BCache is
  implemented on the processor module, and typically uses semiconductor
  memory faster than that of the main system memory.  Both the PCache
  and BCache are subdivided into Instruction (ICache) and DCache, as
  the patterns of references within these two tupes of data are usually
  quite different.
 
  Cache and parity errors can and often will generate error log entries,
  and can potentially also generate machine check (MCHECK) crashes and
  related system stability problems.
 
  The DCache can be automatically disabled, depending on the stability
  of the system hardware environment.   DECevent and Compaq Analyze
  will generally report the (disabled) status of the BCache with a
  statement such as the following:
 
    External Cache (Bcache) Disabled
 
  Recurrent errors within the DCache usually point to the need to replace
  the processor module, though you will want to contact your hardware
  support organization for assistance and for hardware-level details on
  and troubleshooting assistance with your specific Alpha hardware platform.
  If you wish to perform self-maintainance of your hardware, please consider
  the "Assisted Services" program referenced in the FAQ -- this program can
  provide you with access to spares, repairs, diagnostics, and related.
 
 Answer written or last revised on  15-NOV-2002 
