Timing-oriented routers for PCB layout design of high-performance computers

The authors present two timing-oriented routers for PCB (printed circuit board) layout designs of high-performance computers: the recursive pattern-search router and the detour-length driven line router. The recursive pattern-search router is a precise specified-length router, which does not use detour points but, instead, recursively repeats the search procedures using U-shaped and simple patterns such that the wire length is adjusted to the specified value. This router guarantees that a route can be found which satisfies the length constraint if one exists. It is also capable of pairwise routing. The detour-length-driven line router is a diagonal router based on line routing. The router finds a minimal-length route rapidly using diagonal and orthogonal directions. These routers were incorporated into a routing system for PCB layout designs of mainframe computers (e.g. M-880), and they were confirmed as practical.<>