A laptop computer, also known as a notebook computer, is a small personal computer designed for mobile use. A laptop integrates all of the typical components of a desktop computer, including a display, a keyboard, a pointing device (a touchpad, also known as a trackpad, or a pointing stick) and a battery into a single portable unit. The rechargeable battery is charged from an AC/DC adapter and has enough capacity to power the laptop for several hours.
A laptop is usually shaped like a large notebook with thickness of 0.7–1.5 inches (18–38 mm) and dimensions ranging from 10x8 inches (27x22cm, 13" display) to 15x11 inches (39x28cm, 17" display) and up. Modern laptops weigh 3 to 12 pounds (1.4 to 5.4 kg), and some older laptops were even heavier. Most laptops are designed in the flip form factor to protect the screen and the keyboard when closed.
Originally considered "a small niche market"[1] and perceived as suitable for "specialized field applications" such as "the military, the Internal Revenue Service, accountants and sales representatives"[1][2], battery-powered portables had just 2% worldwide market share in 1986[3]. But today, there are already more laptops than desktops in the enterprise[4] and, according to a forecast by Intel, more laptops than desktops will be sold in the general PC market as soon as 2009[5].
History
As the personal computer became feasible in the early 1970s, the idea of a portable personal computer followed; in particular, a "personal, portable information manipulator" was envisioned by Alan Kay at Xerox PARC in 1968[6] and described in his 1972 paper as the "Dynabook"[7].
The first commercially available portable computer appeared nine years later, in 1981. The Osborne 1 weighed 23.5 pounds (10.7 kg). It had no battery, a tiny 5" CRT screen and dual 5¼" single-density floppy drives. In the same year the first laptop-sized portable computer, the Epson HX-20, was announced[8]. The Epson had a LCD screen, a rechargeable battery and a calculator-size printer in a 1.6 kg (4 pounds) enclosure.
The first notebook using the clamshell design, utilized today by almost all laptops, appeared in 1982. The $8150 GRiD Compass 1100 was purchased by NASA and the military among others. The Gavilan SC, released in 1983, was the first notebook marketed using the term "laptop".
From 1983 onwards:
* Several new input methods were introduced: the touchpad (Gavilan SC, 1983), the pointing stick (IBM ThinkPad 700, 1992) and handwriting recognition (Linus Write-Top[9], 1987).
* CPUs became designed specifically for laptops (Intel i386SL, 1990), targeting low power consumption, and were augmented with dynamic power management features (Intel SpeedStep and AMD PowerNow!).
* Displays reached VGA resolution by 1988 (Compaq SLT 286) and 256-color screens by 1993 (PowerBook 165c), progressing quickly to millions of colors and high resolutions.
* High-capacity hard drives and optical storage (CD-ROM followed by DVD) became available in laptops soon after their introduction to the desktops.
Early laptops often had proprietary and incompatible architectures, operating systems and bundled applications.
Subnotebook
A subnotebook, also called an ultraportable by some vendors, is a laptop designed and marketed with an emphasis on portability (small size, low weight and long battery life) that retains the performance of a standard notebook. Subnotebooks are usually smaller and lighter than standard laptops, weighing between 0.8 and 2 kg (2 to 5 pounds)[10]; the battery life can exceed 10 hours[13] when a large battery or an additional battery pack is installed.
To achieve the size and weight reductions, ultraportables use high resolution 13" and smaller screens (down to 6.4"), have relatively few ports, employ expensive components designed for minimal size and best power efficiency, and utilize advanced materials and construction methods. Some subnotebooks achieve a further portability improvement by omitting an optical/removable media drive; in this case they may be paired with a docking station that contains the drive and optionally more ports or an additional battery.
The term "subnotebook" is usually reserved to laptops that run general-purpose desktop operating systems such as Windows, Linux or Mac OS X, rather than specialized software such as Windows CE, Palm OS or Internet Tablet OS.
Netbook
A netbook is a small laptop designed for portability and low price, with a performance inferior to that of a standard notebook yet adequate for surfing on the Internet and basic word processing. Netbooks use 10" and smaller screens, weigh 0.6 to 1.2 kg (1.5 to 3 pounds), and are generally powered by a CPU from one of the low-cost families with a high performance-to-power ratio such as Intel Atom, Celeron ULV, or VIA C7[14] processors.
Netbooks use general-purpose operating systems such as Linux or Windows XP. Some models use small-capacity (4 to 40 Gb) SSD drives instead of the usual HDDs to save weight and battery power.
Rugged Laptop
A rugged (or ruggedized) laptop is designed to reliably operate in harsh usage conditions such as strong vibrations, extreme temperatures and wet or dusty environments. Rugged laptops are usually designed from scratch, rather than adapted from regular consumer laptop models. Rugged notebooks are bulkier, heavier, and much more expensive than regular laptops[15], and thus are seldom seen in regular consumer use.
The design features found in rugged laptops include rubber sheeting under the keyboard keys, sealed port and connector covers, passive cooling, superbright displays easily readable in daylight, cases and frames made of magnesium alloys or have a magnesium alloy rollcage[16] that are much stronger than plastic found in commercial laptops and solid-state storage devices or hard disc drives that are shock mounted to withstand constant vibrations. Rugged laptops are commonly used by public safety services (police, fire and medical emergency), military, utilities, field service technicians, construction, mining and oil drilling personnel. Rugged laptops are usually sold to organizations, rather than individuals, and are rarely marketed via retail channels.
