Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Wed, 13 Apr 2011 10:10:37 -0500

On Wednesday 13 April 2011 09:23:43 Matt Newville wrote:
> > I am also interested to know how far we can go with the array size in
> > EPICS and PyEPICS interface.
> 
> There is no explicit limit on array size that doesn't exist in EPICS.
> With Area Detector, it's not unusual for us to be transferring 8Mb
> arrays.   I don't know what the largest verified array size is, or how
> EPICS would deal with arrays approaching 2Gb.

I think the only issue would be that there has to be enough RAM in the IOC for 
the multiple copies of the data that are made between the device, record and 
CA server.  The record obviously has to have the storage for its copy, and the 
CA server reserves EPICS_CA_MAX_ARRAY_BYTES + a little bit for buffering on 
the way out.  Whatever device support you're using might want its own copy as 
well, but that might be avoidable depending on the actual code in use.

- Andrew
-- 
An error is only a mistake if you don't learn from it.
When you learn something from it, it becomes a lesson.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System