History

Main article: History of laptops

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 imagined by Alan Kay at Xerox PARC in 1968^[8] and described in his 1972 paper as the "Dynabook"^[9].

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 8-bit CPU machines became widely accepted, the number of portables increased rapidly. The Osborne 1 used the Zilog Z80, weighed 23.5 pounds (10.7 kg). It had no battery, only 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^[10]. The Epson had a LCD screen, a rechargeable battery and a calculator-size printer in a 1.6 kg (4 pounds) chassis. Both Tandy/Radio Shack and HP also produced portable computers of varying designs during this period.

The first laptop using the clamshell design, used today by almost all laptops, appeared in 1982. The $8150 GRiD Compass 1100 was used at NASA and by 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 techniques were developed and included in laptops: the touchpad (Gavilan SC, 1983), the pointing stick (IBM ThinkPad 700, 1992) and handwriting recognition (Linus Write-Top^[11], 1987).
• Some CPUs were designed specifically for low power use (including laptops (Intel i386SL, 1990), and were supported by dynamic power management features (Intel SpeedStep and AMD PowerNow!) in some designs.
• 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 CD-R and CD-RW and eventually by DVD-ROM and the writable varieties) became available in laptops soon after their introduction to the desktops.

Early laptops often had proprietary and incompatible system architectures, operating systems, and bundled applications, making third party hardware and software difficult and sometimes impossible to develop.

Classification : ......................

The general terms "laptop" or "notebook" can be used to refer to a number of classes of small portable computers:^[12][13]

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 fewer features, 13" or smaller screen.

By features: 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 suited to Internet surfing and basic office applications. Rugged – Engineered to operate in tough conditions (strong vibrations, extreme temperatures, wet and dusty environments).

[edit] As replacement

Dell XPS M140 Laptop.

Main article: Desktop replacement computer

A desktop replacement computer is a laptop that provides most of the capabilities of a desktop computer, with a similar level of performance. Desktop replacements are usually larger and heavier than standard laptops. They contain more powerful components and numerous ports, and have a 15.4" or larger display. Because of their bulk, they are not as portable as other laptops and their operation time on batteries is typically shorter.^[13]

Some laptops in this class use a limited range of desktop components to provide better performance for the same price at the expense of battery life; in a few of those models, there is no battery at all and the laptop can only be used when plugged in. These are sometimes called desknotes, a portmanteau of the words "desktop" and "notebook," though the term can also be applied to desktop replacement computers in general.^[14]

In the early 2000s, desktops were more powerful, easier to upgrade, and much cheaper in comparison with laptops. But in the last few years, the advantages have drastically changed or shrunk since the performance of laptops has markedly increased.^[15] In the second half of 2008, laptops have finally outsold desktops for the first time ever. In the U.S., the PC shipment declined 10 percent in the forth quarter of 2008. In Asia, the worst PC shipment growth went up 1.8 percent over the same quarter the previous year since PC statistics research started. ^[16]

The names "Media Center Laptops" and "Gaming Laptops" are also used to describe this class of notebooks.^[12]

[edit] Notebook

Although the term Notebook is now often used interchangeably with the term Laptop, it was originally introduced to differentiate a smaller, thinner and lighter range of devices (comparable with a traditional paper notebook) which supplanted their larger counterparts^[1].