Minimization of the width of control memory: a survey

Several algorithms for the minimization of control memory bit dimension are presented and evaluated. Early methods used techniques well known to switching theory, such as compatible classes and cover tables. The drawback in this approach is that the cover tables become unmanageably large for most real applications. The problem was then reformulated in the context of linear programming. However, this method still requires a lot of enumeration and always leads to an absolute minimal solution. A branch-and-bound algorithm is presented. Although it is exponential in the worst case, the procedure is found to be more efficient than the earlier enumerative methods