A laptop computer is a
personal computer designed for mobile use that is small enough to sit on one’s lap. 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 10×8 inches (27x22cm, 13″ display) to 15×11 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” and perceived as suitable for “specialized field applications” such as “the military, the Internal Revenue Service, accountants and sales representatives”, battery-powered portables had just 2% worldwide market share in 1986. But today, there are already more laptops than desktops in the enterprise and, according to a forecast by Intel, more laptops than desktops will be sold in the general PC market as soon as 2009.
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 and described in his 1972 paper as the “Dynabook“.
The I.B.M. SCAMP project (Special Computer APL Machine Portable), was demonstrated in 1973. This prototype was based on the PALM processor (Put All Logic In Microcode).
The I.B.M. 5100, the first commercially available portable computer, appeared in September 1975, and was based on the SCAMP prototype.
As the 8-bit C.P.U. became more widely accepted, the number of portables increased rapidly. Based on the Zilog Z80, 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. The Epson had a LCD screen, a rechargeable battery and a calculator-size printer in a 1.6 kg (4 pounds) enclosure.
The first laptop 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, 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.
The general terms “laptop” or “notebook” can be used to refer to a number of classes of small portable computers:
|By purpose and (approximately) by screen size:
- Desktop replacement – emphasizes performance, is less portable, 15″ and larger screen;
- Standard laptop – balances portability and features, 13-15″ screen;
- Subnotebook – emphasizes portability, has less features, 13″ or smaller screen.
- Budget – a cheap, lower-performance standard-sized laptop;
- Tablet PC – Has a touch-screen interface, may or may not have a keyboard;
- Netbook – A cheaper, smaller version of a subnotebook designed mainly for Internet surfing and basic office applications.
- Rugged – Engineered to operate in tough conditions (strong vibrations, extreme temperatures, wet and dusty environments).