When Radio Shack released the Model 100 in 1983, it was a breakthrough for portable computing: an AA-battery-powered laptop that you could fit in a briefcase, with a built-in modem and an instant-on Microsoft OS that contained the last production code Bill Gates ever wrote himself. The Model 100 was so seminal that it had its own sales-training literature, including Selling the TRS-80 Model 100, an industrial training film designed to help Radio Shack clerks explain why a customer should shell out for the $800 system. Most of this is a straightforward walk-through of the Model 100’s capabilities by a guy with a stentorian voice.