Hi Steve -
I don't have example code, but OnCommand System Manager uses SNMP.
You can do an SNMP get with OID 1.3.6.1.2.1.1.1.0. You should get a response like:
NetApp Release RironcityN_110125_2230: Wed Jan 26 00:55:17 PST 2011 or
NetApp Release 8.1.1 Cluster-Mode: Mon Jul 30 16:46:29 PDT 2012
The key is to look for NetApp.
You can also do an SNMP get with OID 1.3.6.1.4.1.789.1.1.2.0 which will also return the above values. Usiing 1.3.6.1.4.1.789 makes the OID NetApp specific.
You will probably want to do it with multiple threads in parallel, because of the SNMP time-out. With multiple threads, you'll discover controllers much faster.
I hope this helps,
- Rick -