An Ultra-Mobile Personal Computer (Ultra-Mobile PC or UMPC) is a type of computing device designed to deliver a traditional PC-style experience in a very small and portable package. There is no widely agreed upon definition for the types of devices that fit into this category, but UMPCs are generally smaller than a laptop and larger than a smartphone, with screen sizes ranging from about 4 to 8 inches (10 to 20 cm). They are most often equipped with a traditional PC operating system and may use a keyboard, touchscreen, or both for input.
The Ultra-Mobile PC category was created in 2006 by Microsoft™ and several of its hardware partners to bridge the gap in size and performance between smartphones and laptop computers. Like laptops, UMPCs are capable of a variety of different purposes and have much in common with a desktop PC. Many use slightly modified versions of traditional PC operating systems. Similar to many smartphones, UMPCs may sacrifice features like performance and ergonomics in the interest of maximum portability.
There is no standard metric for what exactly constitutes an Ultra-Mobile PC, though most feature a touchscreen between 4 and 8 inches (10 to 20 cm). The earliest devices marketed under the term had screens about 7 inches (17.8 cm) across, but both larger and smaller devices have since been released. UMPCs may overlap in size with other types of computing devices; very small UMPCs can be about the same size as a smaller product known as a Mobile Internet Device, while larger products can look similar to tablets and netbooks.
One feature that can distinguish Ultra-Mobile PCs from other devices is the ability to use traditional PC operating systems. While smartphones, tablets, and other devices often operate on specially crafted software platforms, UMPCs generally run the same type of operating system found on laptops and desktop PCs. The first devices to be marketed under the term used a version of Windows XP with additional software to facilitate touchscreen input, while more contemporary UMPCs may run Windows Vista, Windows 7, or a version of Linux.
The design of UMPCs vary greatly; the only common attributes generally are a small footprint and light weight. An Ultra-Mobile PC might use a touchscreen, a keyboard, a pointing device such as a joystick, or some combination of these for input. They may feature a slide-out keyboard similar to a smartphone, a mini-tablet design, or a clamshell setup found in traditional laptops. Most feature internal storage of some sort and a wide variety of standard connectivity options such as Universal Serial Bus (USB) ports and Wi-Fi networking.
Although the Ultra-Mobile PC idea was met with initial enthusiasm by industry commentators, the actual products met with a lukewarm reaction. Critics pointed to the high cost, relatively poor battery life, and difficulty of use as major obstacles to mass-market adoption. Beginning in late 2008, the Ultra-Mobile PC began to be overshadowed by netbooks, tablets, and other devices. UMPCs continue to be manufactured as niche devices but have never captured the attention of mainstream consumers.