Since long before the iPad launched in 2010, tablets have fascinated consumers and vendors alike. Apple introduced the Newton Message Pad in 1993. Microsoft took a run in 1991 with its Pen Computing initiative that never took off. In 2002, Microsoft tried again with its XP for Tablet PC, which did better. But it wasn’t until the iPad that a tablet with an intuitive touch interface caught the imagination, and since then it’s been an all-out rush to duplicate that success. As Microsoft launches another attempt with its Surface for Windows RT announcement, here’s a look at some of the predecessors.