CMN-GOMS is the original version of the GOMS technique in human computer interaction.
It takes the name after its creators Stuart Card, Thomas P. Moran and Allen Newell who first described GOMS in their 1983 book The Psychology of Human Computer Interaction.
The structure is rigid enough that the evaluator represents the tasks in a pseudo-code format (no formal syntax is dictated).
For instance, examining the number of levels down the task-tree that a goal branch is can be used to estimate the memory demand the task places on the system.
That is, it can be executed for different scenarios by going down different branches, while KLM's procedure is a simple list that has to be recreated for each different task.