Given a supercompact cardinal κ and a regular cardinal λ < κ, we describe a type of forcing such that in the generic extension the cofinality of κ is λ, there is a very good scale at κ, a bad scale at κ, and SCH at κ fails. When creating our model we have great freedom in assigning the value of 2κ, and so we can make SCH hold or fail arbitrarily badly.
"A model for a very good scale and a bad scale." J. Symbolic Logic 73 (4) 1361 - 1372, December 2008. https://doi.org/10.2178/jsl/1230396925