A standard laptop combines the components, inputs, outputs, and capabilities of a desktop computer, including the display screen, small speakers, a keyboard, hard disk drive, optical disc drive pointing devices (such as a touchpad or trackpad), a processor, and memory into a single unit. Most 2016-era laptops also have integrated webcams and built-in microphones. Some 2016-era laptops have touchscreens. Laptops can be powered either from an internal battery or by an external power supply from an AC adapter. Hardware specifications, such as the processor speed and memory capacity, significantly vary between different types, makes, models and price points.

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Design elements, form factor and construction can also vary significantly between models depending on intended use. Examples of specialized models of laptops include rugged notebooks for use in construction or military applications, as well as low production cost laptops such as those from the One Laptop per Child organization, which incorporate features like solar charging and semi-flexible components not found on most laptop computers. Portable computers, which later developed into modern laptops, were originally considered to be a small niche market, mostly for specialized field applications, such as in the military, for accountants, or for traveling sales representatives. As portable computers evolved into the modern laptop, they became widely used for a variety of purposes.

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The terms laptop and notebook are used interchangeably to describe a portable computer in English, although in some parts of the world one or the other may be preferred. There is some question as to the original etymology and specificity of either term—the term laptopappears to have been coined in the early 1980s to describe a mobile computer which could be used on one's lap, and to distinguish these devices from earlier, much heavier, portable computers (informally called "luggables"). The term "notebook" appears to have gained currency somewhat later as manufacturers started producing even smaller portable devices, further reducing their weight and size and incorporating a display roughly the size of A4 paper; these were marketed as notebooks to distinguish them from bulkier laptops. Regardless of the etymology, by the late 1990s, the terms were interchangeable.

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As the personal computer (PC) became feasible in 1971, the idea of a portable personal computer soon followed. A "personal, portable information manipulator" was imagined by Alan Kay at Xerox PARC in 1968, and described in his 1972 paper as the "Dynabook". The IBM Special Computer APL Machine Portable (SCAMP) was demonstrated in 1973. This prototype was based on the IBM PALM processor. The IBM 5100, the first commercially available portable computer, appeared in September 1975, and was based on the SCAMP prototype.

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As 8-bit CPU machines became widely accepted, the number of portables increased rapidly. The first laptop-sized notebook computer was the Epson HX-20, invented (patented) by Suwa Seikosha's Yukio Yokozawa in July 1980, introduced at the COMDEX computer show in Las Vegas by Japanese company Seiko Epson in 1981,and widely released in 1982. It had an LCD screen, a rechargeable battery, and a calculator-size printer, in a 1.6 kg (3.5 lb) chassis, the size of an A4 notebook. It was described as a "laptop" and "notebook" computer in its patent.