From ECDL.web

A laptop (or notebook) is a personal computer for mobile use.

A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device (a touchpad, also known as a trackpad) and speakers into a single unit.

A laptop is powered by mains electricity via an AC adapter, and can be used away from an outlet using a rechargeable battery. A laptop battery in new condition typically stores enough energy to run the laptop for three to five hours, depending on the computer usage, configuration and power management settings. When the laptop is plugged into the mains, the battery charges, whether or not the computer is running.

Portable computers were originally considered to be a small niche market, mostly for specialized field applications such as the military, accountants and sales representatives. As portable computers became smaller, lighter, and cheaper and as screens became larger and of better quality, laptops became very widely used for all sorts of purposes.

[edit] History

As the personal computer became feasible in the early 1970s, the idea of a portable personal computer 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 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 IBM 5100, the first commercially available portable computer, appeared in September 1975, and was based on the SCAMP prototype.

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 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.

From 1983 onward, several new input techniques were developed and included in laptops, including the touchpad, the pointing stick and handwriting recognition. 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 VGA resolution by 1988, and colour 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, became common in laptops soon in the 2000s.

[edit] Classification

• Full-size Laptop: A laptop large enough to accommodate a "full-size" keyboard (a keyboard with the minimum QWERTY key layout). The measurement of at least 11 inches across has been suggested as the threshold for this class. The first laptops were the size of a standard U.S. "A size" notebook sheet of paper (8.5 × 11 inches), but later "A4-size" laptops were introduced, which were the width of a standard ISO 216 A4 sheet of paper (297 mm, or about 11.7 inches), and added a vertical column of keys to the right and wider screens. 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 have a 15" or larger display.

• Netbook: A smaller, lighter, more portable laptop. It is also usually cheaper than a full-size laptop, but has fewer features and less computing power. Smaller keyboards can be more difficult to operate. There is no sharp line of demarcation between netbooks and inexpensive small laptops; some 11.6" models are marketed as netbooks. Since netbooks, compared to laptops, are quite small in size, CDs cannot be used in these computers.
• A subnotebook or ultraportable, is a laptop designed and marketed with an emphasis on portability (small size, low weight and often longer battery life) that retains performance close to that of a standard notebook. Subnotebooks are usually smaller and lighter than standard laptops, weighing between 0.8 and 2 kg (2 to 5 pounds); the battery life can exceed 10 hours.

• Tablet PCs are "convertible tablets" with a full keyboard where the screen rotates to be used atop the keyboard, and "slate" form-factor machines which are usually touch-screen only (although a few older models feature very small keyboards along the sides of the screen).
• Rugged: Engineered to operate in tough conditions (mechanical shocks, extreme temperatures, wet and dusty environments).

[edit] Advantages

Portability is usually the first feature mentioned in any comparison of laptops versus desktop PCs. Portability means that a laptop can be used in many places—not only at home and at the office, but also during commuting and flights, in coffee shops, in lecture halls and libraries, at clients' location or at a meeting room, etc. The portability feature offers several distinct advantages:

• Productivity: Using a laptop in places where a desktop PC can not be used, and at times that would otherwise be wasted. For example, an office worker managing their e-mails during an hour-long commute by train, or a student doing his/her homework at the university coffee shop during a break between lectures.
• Immediacy: Carrying a laptop means having instant access to various information, personal and work files. Immediacy allows better collaboration between coworkers or students, as a laptop can be flipped open to present a problem or a solution anytime, anywhere.
• Up-to-date information: If a person has more than one desktop PC, a problem of synchronization arises: changes made on one computer are not automatically propagated to the others. There are ways to resolve this problem, including physical transfer of updated files (using a USB flash memory stick or CDRs) or using synchronization software over the Internet. However, using a single laptop at both locations avoids the problem entirely, as the files exist in a single location and are always up-to-date.
• Connectivity: A proliferation of WiFi wireless networks and cellular broadband data services combined with a near-ubiquitous support by laptops means that a laptop can have easy Internet and local network connectivity while remaining mobile. WiFi networks and laptop programs are especially widespread at university campuses.

Other advantages of laptops:

• Size: Laptops are smaller than desktop PCs. This is beneficial when space is at a premium, for example in small apartments and student dorms. When not in use, a laptop can be closed and put away.
• Low power consumption: Laptops are several times more power-efficient than desktops. A typical laptop uses 20–90 W, compared to 100–800 W for desktops. This could be particularly beneficial for businesses (which run hundreds of personal computers, multiplying the potential savings) and homes where there is a computer running 24/7 (such as a home media server, print server, etc.)
• Quiet: Laptops are often quieter than desktops, due both to the components (quieter, slower 2.5-inch hard drives) and to less heat production leading to use of fewer and slower cooling fans.
• Battery: a charged laptop can continue to be used in case of a power outage and is not affected by short power interruptions and blackouts. A desktop PC needs a UPS to handle short interruptions, blackouts and spikes; achieving on-battery time of more than 20–30 minutes for a desktop PC requires a large and expensive UPS.
• All-in-One: designed to be portable, laptops have everything integrated in to the chassis. For desktops this is usually divided into the desktop, keyboard, mouse, display, and optional peripherals such as speakers.

[edit] Disadvantages

Compared to desktop PCs, laptops have disadvantages in the following fields:

• Performance: While the performance of mainstream desktops and laptops is comparable, and the cost of laptops has fallen more rapidly than desktops, laptops remain more expensive than desktop PCs at the same performance level.
• Upgradeability of laptops is very limited compared to desktops, which are thoroughly standardized. In general, hard drives and memory can be upgraded easily. Optical drives and internal expansion cards may be upgraded if they follow an industry standard, but all other internal components, including the motherboard, CPU and graphics, are not always intended to be upgradeable.
• Durability: Due to their portability, laptops are subject to more wear and physical damage than desktops. Components such as screen hinges, latches, power jacks and power cords deteriorate gradually due to ordinary use. A liquid spill onto the keyboard, a rather minor mishap with a desktop system, can damage the internals of a laptop and result in a costly repair. Laptops rely on extremely compact cooling systems involving a fan and heat sink that can fail due to eventual clogging by accumulated airborne dust. Battery life is limited because the capacity drops with time, necessitating an eventual replacement after a few years.
• Security and privacy: Because they are valuable, common, and portable, laptops are prized targets for theft. The cost of stolen business or personal data, and of the resulting problems (identity theft, credit card fraud, breach of privacy), can be many times the value of the stolen laptop itself. Consequently, physical protection of laptops and the safeguarding of data contained on them are both of great importance. Most laptops have a Kensington security slot, which can be used to tether them to a desk or other immovable object with a security cable and lock. In addition, modern operating systems and third-party software offer disk encryption functionality, which renders the data on the laptop's hard drive unreadable without a key or a pass phrase.
• Ergonomics and health issues: Because of their small and flat keyboard and trackpad pointing devices, prolonged use of laptops can cause repetitive strain injury on the wrists. The integrated screen often causes users to hunch over for a better view, which can cause neck or spinal injuries. Heat generated from laptops can raise the temperature of the user's lap when balancing the computer on one's lap, potentially putting male fertility at risk. Heat from using a laptop on the lap can also cause skin discoloration on the thighs known as "toasted skin syndrome".

[edit] Major brands and manufacturers

There is a multitude of laptop brands and manufacturers; several major brands, offering notebooks in various classes, are:

• Acer / Gateway: TravelMate, Extensa, Ferrari and Aspire, Packard Bell Easynote
• Apple: MacBook, MacBook Air and MacBook Pro
• Asus: Eee, Lamborghini, ASUS G Series(ROG)
• Dell: Alienware, Inspiron, Latitude, Precision, Studio, Vostro and XPS
• Fujitsu: Lifebook
• HP / Compaq: HP Pavilion, HP ProBook, Compaq Presario
• Lenovo: ThinkPad, IdeaPad, and 3000 series
• LG: Xnote
• MSI: E(ntertainment), C(lassic), P(rofessional), G(aming), V(alue), A(esthetic), X(Slim), U series and Wind Netbook
• Samsung: SENS N, P, Q, R and X series
• Sony: Vaio
• Toshiba: Dynabook, Portege, Tecra, Satellite, Qosmio, Libretto

The major brands usually offer good service and support, including well-executed documentation and driver downloads that will remain available for many years after a particular laptop model is no longer produced. Capitalizing on service, support and brand image, laptops from major brands are more expensive than laptops by smaller brands and ODMs. Many brands, including the major ones, do not design and do not manufacture their laptops. Instead, a small number of Original Design Manufacturers (ODMs) design new models of laptops, and the brands choose the models to be included in their lineup. In 2006, 7 major ODMs manufactured 7 of every 10 laptops in the world, with the largest one (Quanta Computer) having 30% world market share.