Question about unicity distance

[kckluge]

This is a one-way encryption. Almost impossible to get back to the original. But why would the authors of the VMS want to do this?

The question wasn't whether Brumbaugh was wrong -- it's clear he was -- it was a specific technical question about how to compute unicity distance for such a cipher. Even with multiple options for individual words, there almost certainly has to be some text length such that only one set of possible options for the words forms a coherent text.