Subnotebook

Subnotebook, also called ultraportable, superportable, handtop, mini notebook or mini laptop, is a type of laptop computer that is smaller and lighter than a typical notebook-sized laptop.

As typical laptop sizes have decreased over the course of the 2010s, and other distinguishing features have become mainstream, the distinction between regular-size and 'subnotebook' laptops has largely disappeared. To the extent that it still exists, 'subnotebook' could be defined as machines with screen smaller than 13" but with a permanently-attached keyboard intended for two-handed typing.

Prior to this convergence, subnotebooks were also distinguished from netbooks and ultra-mobile PCs, based on both size and market position. Subnotebooks run full desktop class operating systems, and their CPUs are usually the same as those in desktops although perhaps modified for lower power consumption.

Classic subnotebooks were smaller than full-sized laptops but larger than handheld computers. They were distinguished by smaller screens and bodies and lighter weights relative to contemporaneous laptops. The savings in size and weight were often achieved partly by omitting ports, and these were typically the first machines to omit optical disc drives or on some of the earliest models, floppy disk drives.

They were also some of the first systems which could be paired with docking stations to compensate. One notable form-factor of subnotebook-oriented docks were "slice docks" — a more transportable version of the classic docking station.

The Epson HX-20, released in 1982, was the first portable computer to be classified by journalists as a "notebook computer". This nomenclature derives from its footprint roughly occupying the same dimensions as an A4-sized notebook, small enough to fit inside a briefcase. The similarly designed TRS-80 Model 100 from 1983 was the first commercially successful notebook and is credited with spawning an industry of smaller portable computers. Like the HX-20, the Model 100 was smaller than contemporary clam-shell machines; both use a slate form factor, with no hinge and the keyboard and screen on the same plane. The Model 100's later sibling the Tandy 200 was a clam-shell design and smaller than contemporary laptops.

The NEC UltraLite, launched in 1988, was the first clamshell "notebook computer" compatible with the IBM PC, a platform whose market share dominated the microcomputer industry throughout the 1980s onward. Its relatively small dimensions — 48 × 220 × 280 mm (1.4 × 8.3 × 11.75 inches) — matched those of a pair of stacked US Letter (similar to A4) size paper notebooks. Owing to its lack of a floppy drive (in favor of proprietary solid-state storage), the UltraLite did not see massive uptake by the general public. The first commercially successful notebook in this vein, the Compaq LTE, was released in 1989 to critical acclaim and high sales. The success of the LTE convinced IBM and Apple to release their own slimmer laptops, starting with the PS/2 Model L40 SX and the PowerBook 100, respectively. IBM replaced the L40 SX with the PS/2 note in early 1992 and the ThinkPad line in late 1992.

There were also a few notable smaller-than subnotebook PCs at this time, including the Atari Portfolio and HP 95LX — both very small MS-DOS machines, roughly comparable in size to later handheld PCs.