Other early models were the Poqet PC of 1989 and the Hewlett Packard HP 95LX of 1991 which run the MS-DOS operating system.

The popular definition of "handheld PC" eventually became a device bigger than a personal digital assistant (PDA) and with the addition of a keyboard that folds in half (making it more similar to a laptop rather than for example a cell phone) with both PDAs and handheld PCs considered under the umbrella "palmtop computer".

[3][4]After 2000 the handheld PC segment practically halted, replaced by other forms and continuing only as a niche, although later communicators such as Nokia E90 or Toshiba Portégé G910[5] can be considered to be of the same class.

On the other hand, ultra-compact laptops capable of running common x86-compatible desktop operating systems have been typically classified as subnotebooks.

Microsoft's ultra-mobile PC brought x86-based Windows — typically the modern definition of 'PC' — to palm sized mobile devices for the first time and these have also been referred to as handheld PCs.

To be classed as a Windows CE Handheld PC, the device must:[10] HP's first displays' widths were more than a third larger than that of Microsoft's specification.

[12] In October 1998, Handheld PC Professional based on Windows CE 2.11 was released with many enhancements under the hood, as well as full VGA display resolution.