This DateAndTime value is the timestamp of the last update to the finite-state-machine running against this internal backplane link. It matters on the internal Ethernet link that carries a blade's traffic from the chassis I/O Module up to a Fabric Interconnect over the backplane because comparing this timestamp against the current time is how an admin tells whether a workflow is actively progressing or has silently stopped updating. An fsmStamp on this backplane link that hasn't advanced in over twenty minutes, while fsmStatus still shows 'in progress,' indicates the workflow has effectively hung.