It's been nearly ten years since the Cupertino-based company dabbled in the realm of sub-notebooks, but for a stint of several years in the early-to-mid '90s, its PowerBook series help set the benchmark for ultraportable computing as we see it today. By introducing the PowerBook 100 in October of 1991, Apple pioneered innovations that are now de facto standards on all notebook systems, such as the rear placement of the keyboard, a palm rest for users to place their hands, and the inclusion of the trackball (which eventually gave way to the trackpad).
