A Palmtop PC was an about pocket calculator-sized, battery-powered PC in a horizontal clamshell design with integrated keyboard and display. It could be used like a subnotebook, but was light enough to be comfortably used handheld as well. Most Palmtop PCs were small enough to be stored in a user's shirt or jacket pocket.Palmtop PCs distinguish from other palmtop computers by utilizing a mostly IBM-compatible PC architecture and BIOS as well as an Intel-compatible x86 processor.