A laptop, often called a notebook, or notebook computer, is a portable personal computer with a "clamshell" form factor, with a keyboard on the lower part of the "clamshell" and a thin LCD/LED computer screen on the upper portion, which is opened up to use the computer. Laptops are folded shut for transportation, and thus are suitable for mobile use.[1] Although originally there was a distinction between laptops and notebooks, the former being bigger and heavier than the latter, as of 2014, there is often no longer any difference.[2] Laptops are commonly used in a variety of settings, such as at work, in education, and for personal multimedia and home computer use.
A laptop combines the components, inputs, outputs and capabilities of a desktop computer, including the display screen, speakers, a keyboard, 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. The device can be powered either from a rechargeable battery or by mains electricity from an AC adapter. The hardware specifications, such as the processor speed and memory capacity significantly vary between different types, makes, and models. 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 offerings 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 accountancy, or for travelling sales representatives. As portable computers became closer to the modern laptop, they became widely used for a variety of purposes.[3]
Contents [hide]
1 Term variants
2 History
3 Classification
3.1 Traditional laptop
3.2 Subnotebook
3.3 Netbook
3.4 Convertible, hybrid, 2-in-1
3.5 Desktop replacement
3.6 Rugged notebook
4 Components
4.1 Display
4.2 Central processing unit
4.3 Graphical processing unit
4.4 Memory
4.5 Internal storage
4.6 Removable media drive
4.7 Input
4.8 I/O ports
4.9 Expansion cards
4.10 Battery and power supply
4.11 Cooling
4.12 Docking station
4.13 Charging trolleys
4.14 Solar panel
5 Advantages
6 Disadvantages
6.1 Performance
6.2 Upgradeability
6.3 Ergonomics and health effects
6.3.1 Wrists
6.3.2 Neck and spinal
6.3.3 Possible effect on fertility
6.3.4 Thighs
6.4 Durability
6.4.1 Equipment wear
6.4.2 Parts replacement
6.4.3 Heating and cooling
6.4.4 Battery life
6.5 Security and privacy
7 Major brands and manufacturers
8 Sales
9 Extreme environments
10 Accessories
11 Obsolete features
12 See also
13 References
14 External links
Term variants[edit]
The terms laptop and notebook are used fairly 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 laptop appears to have been coined in the early 1980s to describe a mobile computer which can be used on one's lap, and to distinguish these devices from earlier, much heavier, portable computers (often called "luggables" in retrospect). 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.[4] Regardless of the etymology, by the late 1990s, the terms were interchangeable.
History[edit]
Main article: History of laptops
Alan Kay with his 1972 "Dynabook" prototype (photo: 2008 in Mountain View, California)
The Epson HX-20 was first sold to the public in 1981
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,[5] and described in his 1972 paper as the "Dynabook".[6] The IBM Special Computer APL Machine Portable (SCAMP) was demonstrated in 1973. This prototype was based on the IBM PALM processor.[7] The IBM 5100, the first commercially available portable computer, appeared in September 1975, and was based on the SCAMP prototype.[8]
As 8-bit CPU machines became widely accepted, the number of portables increased rapidly. The Osborne 1, released in 1981, used the Zilog Z80 and weighed 23.6 pounds (10.7 kg). It had no battery, a 5 in (13 cm) CRT screen, and dual 5.25 in (13.3 cm) single-density floppy drives. In the same year the first laptop-sized portable computer, the Epson HX-20, was announced.[9] The Epson had a LCD screen, a rechargeable battery, and a calculator-size printer in a 1.6 kg (3.5 lb) chassis. Both Tandy/RadioShack and HP also produced portable computers of varying designs during this period.[10][11]
The first laptops using the flip form factor appeared in the early 1980s. The Dulmont Magnum was released in Australia in 1981–82, but was not marketed internationally until 1984–85. The US$8,150 (US$19,980 today) GRiD Compass 1100, released in 1982, was used at NASA and by the military among others. The Gavilan SC, released in 1983, was the first computer described as a "laptop" by its manufacturer.[12] From 1983 onward, several new input techniques were developed and included in laptops, including the touchpad (Gavilan SC, 1983), the pointing stick (IBM ThinkPad 700, 1992) and handwriting recognition (Linus Write-Top,[13] 1987). Some CPUs, such as the 1990 Intel i386SL, were designed to use minimum power to increase battery life of portable computers and were supported by dynamic power management features such as Intel SpeedStep and AMD PowerNow! in some designs.
Displays reached 640x480 (VGA) resolution by 1988 (Compaq SLT/286), and color screens started becoming a common upgrade in 1991 with increases in resolution and screen size occurring frequently until the introduction of 17" screen laptops in 2003. Hard drives started to be used in portables, encouraged by the introduction of 3.5" drives in the late 1980s, and became common in laptops starting with the introduction of 2.5" and smaller drives around 1990; capacities have typically lagged behind physically larger desktop drives. Optical storage, read-only CD-ROM followed by writeable CD and later read-only or writeable DVD and Blu-ray players, became common in laptops early in the 2000s.
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