With Mad Men entering its final season next month, AMC is in need of a new period drama to hang its hat on. Halt and Catch Fire may be the ticket, and it already looks like the networks answer to HBOs Silicon Valley. As the title — a play on old machine code that causes a computer to stop functioning — hints at, the show will follow the drama and nastiness that arose around the time IBM ruled the computing world. Lee Pace, as former IBM engineer Joe MacMillan, cuts an imposing figure in the spot, which should come as no surprise for those who saw his turn in The Hobbit last year. …