[Beowulf] What is rdma, ofed, verbs, psm etc?

[Faraz Hussain]

Thanks Peter for the high level overview! A few followup questions.  
What if I am using a non-Infiniband cluster, i.e something with  
10gigE.  Or even slower like at my home I have a raspbery pi cluster  
with 100 Mbps ethernet. Is ofed/psm/verbs all irrelevant? If so, what  
would their equivalents be? I assume RDMA is still applicable since I  
can run openmpi on these clusters.

Another question, who is typically responsible for tuning  
ofed/psm/verbs etc on an Infiniband cluster? Is it generally the  
vendor who builds the cluster or the sys.admin? My role has always  
been more user-facing application support. But I am wondering how much  
time I should invest in learning the inner workings of ofed/psm/verbs  
etc?