I/O Interrupt Scanning for Soft Records

[Andy Foster <ajf@ast.cam.ac.uk>]

As part of the software control of the Gemini Telescopes,
we wish to be able to cause record processing in a source IOC 
as a result of monitoring the output of a record in a 
destination IOC. 

The Gemini control software is split into distinct subsystems
which are spread across several IOC's.
Our specifications state that the lower level systems should not
have any knowledge of the higher level systems. We are trying to 
work out how the higher level systems should monitor status 
information from the lower level systems without polling.

We would like to have stringin, ai and bi soft records in the source
IOC monitoring outputs from the destination IOC, and for the records
in the source IOC to be processed when the remote outputs (destination
IOC) change. (This is not the same as wanting to set .PP on an 
input-link, which would cause the processing chain to go the other way.)
I believe Channel-Access allows this, since it can be done through a 'C' 
or SNL program by setting a monitor on the output record. However, this
seems a waste.

Could the soft records be modified to support I/O Interrupt scanning 
when their input is a CA link, such that when the CA monitor is 
triggered it causes record processing?  

Any hints on how we should go about doing this?

==========================================================================
Andy Foster
Royal Greenwich Observatory		Tel:    44 (0)1223 374899 (direct)
Madingley Road				E-mail: ajf@ast.cam.ac.uk
Cambridge
CB3 0HA
UK