http://blogs.technet.com/windowshpc/archive/2009/07/04/warning-not-all-infiniband-hcas-have-a-psid.aspxIf you read the documents posted by Mellanox about their new 2..0.5 build 4453 InfiniBand drivers you may have noticed the advice to update your firmware. If so, you will need to discover your PSID. This should be pretty straight forward, just installen-USCommunityServer 2.1 SP1 (Build: 61025.2)