Handheld PC
A handheld personal computer (PC), typically built around either a clamshell form factor or a gaming form factor with a gamepad integrated for video games, is a mobile device that is significantly smaller than any standard personal computer (PC), but based on the same principles as PCs. The clamshell form factor is sometimes referred to as a palmtop computer, not to be confused with Palmtop PC which was a name used mainly by Hewlett-Packard.
Until recently, most handheld PCs used an operating system specifically designed for mobile use. Ultra-compact laptops capable of running common x86-compatible desktop operating systems are typically classified as subnotebooks.
The name Handheld PC was used by Microsoft from 1996 until the early 2000s to describe a category of small computers having keyboards and running the Windows CE operating system.