CMMI (Capability Maturity Model Integration) is a system of improving the efficiency and throughput of various business processes.  Although computer software is involved, CMMI is not strictly just a computer program but a way of obtaining and evaluating data overall.  It was developed in the 1990's by a consortium of government and business people working in conjunction with the Software Engineering Institute at Carnegie Mellon University.  It is highly flexible across a range of uses including pinpointing and solving specific problems within an organization or simply monitoring a wide range of business processes for constant evaluation.  Since CMMI by definition is a process, one does not really "achieve" CMMI.  There is no set endpoint where you have completed the task.  It is an ongoing process to monitor and constantly improve an organization's workflow.