The buffering feature makes use of shared resources in the operating system as a means of providing communication
between the PI-API functions and the buffering process. The buffering process, implemented by the
program, is responsible for initially creating these resources and making them available to the PI-API functions.
Note: When buffering is configured to be on, the bufserv process must be started before other programs using the PI-API so that these programs can access the shared buffering resources. Any program that makes a connection to a PI Server has this requirement even if it does not write to PI.
On Windows, the service dependencies can be used to ensure that the bufserv service is started before the PI interface services. The PI interface services should be configured to have
bufserv as a dependency.
On UNIX platforms, the PI API processes should be started via the
pistart.sh script. If buffering is enabled then the
pistart script will start the
bufserv process. The
sitestart script is run last, and this script should be used to start the PI API interfaces.