Sub-notebook

A subnotebook (also called an ultraportable, superportable or mini notebook) is a class of laptop computers that are smaller and lighter than a typical notebook.

These computers are sometimes confused with the ultra-mobile PC category, which is the name of a platform of small form-factor tablet PCs. UMPCs are smaller than subnotebooks, however both generally are found to run full desktop operating systems such as Windows or Linux, rather than specialized software such as Windows CE, Palm OS, or Internet Tablet OS. Subnotebooks are also sometimes confused with netbooks which are a different category of devices that branched off from mini notebooks in general. Netbooks are most often much less expensive than subnotebooks, as they are optimized for use as portable Internet capable devices and generally lack the processing power of a workstation. Netbooks typically have 9W TDP CPUs, sacrificing performance for power efficiency, whereas subnotebooks often use 18W TDP processors.

Subnotebooks are smaller than full sized laptops but larger than handheld computers. They often have smaller-sized screens, less than 14 inches, and weigh less than typical laptops, usually being less than 2 kg (4.4 lbs). The savings in size and weight are usually achieved partly by omitting ports and optical disc drives. Many can be paired with docking stations to compensate.

The Compaq LTE, launched in 1989, was the first to be widely known as a "notebook computer" because its relatively small dimensions — 4.8×22×28 cm (1.9 × 8.5 × 11 inches) — matched those of a pair of stacked US Letter (similar to A4) size paper notebooks. The Compaq was followed in October 1992 by the very popular IBM ThinkPad, which was the first to include a 26.416 cm (10.4 inch diagonal, 8.3 x 6.2 inch outline) screen in a notebook measuring 5.6 × 21.1 × 28.4 cm (2.2 × 8.3 × 11.7 inches). Portables with noticeably smaller form factors thus became known as subnotebooks. The term was also applied to the NEC UltraLite, unveiled in 1988 — although its dimensions (1.4 × 8.3 × 11.75 inches) were very similar to the Compaq LTE.

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