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					Laptop
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An ultraportable IBM X31 with 12" screen on an IBM T43 Thin & Light laptop with a
14" screen
       This article portrays portable computers, for topics concerning the upper thigh or
       leg see lap.

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].


Contents
[hide]

        1 History
        2 Classification
            o 2.1 As replacement
            o 2.2 Subnotebook
            o 2.3 Netbook
            o 2.4 Rugged Laptop
        3 Components
            o 3.1 Docking stations
            o 3.2 Standards
      4 Advantages
      5 Disadvantages
          o 5.1 Performance
          o 5.2 Upgradeability
          o 5.3 Ergonomics and health
          o 5.4 Durability
          o 5.5 Security
      6 Other portable computing devices
      7 Major brands and manufacturers
      8 Sales
      9 See also
      10 References



[edit] History
       Main article: History of laptops




The Epson HX-20

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 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[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.

[edit] Classification
The general terms "laptop" or "notebook" can be used to refer to a number of classes of
small portable computers:[10][11]

By purpose and (approximately) by screen        By features:
size:
                                                      Budget - a cheap, lower-
      Desktop replacement - emphasizes                performance standard-sized laptop;
       performance, is less portable, 15"             Tablet PC - Has a touch-screen
       and larger screen;                              interface, may or may not have a
      Standard laptop - balances                      keyboard;
       portability and features, 13-15"               Netbook - A cheaper, smaller
       screen;                                         version of a subnotebook designed
      Subnotebook - emphasizes                        mainly for Internet surfing and basic
       portability, has less features, 13" or          office applications.
       smaller screen.                                Rugged - Engineered to operate in
                                                       tough conditions (strong vibrations,
                                                       extreme temperatures, wet and dusty
                                                       environments).


[edit] As replacement
An Apple 17" MacBook Pro is often used as a desktop replacement.
      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.[11]

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.[12]

The names "Media Center Laptops" and "Gaming Laptops" are also used to describe
this class of notebooks.[10]

[edit] Subnotebook




Sony VAIO C1 subnotebook.
      Main article: 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.

[edit] Netbook



An Asus Eee PC netbook.
      Main article: 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
processors.[14]

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.

[edit] Rugged Laptop

       Main article: Rugged computer




A Panasonic Toughbook.
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.

[edit] Components
       Main article: Computer hardware


Miniaturization: a comparison of a desktop computer motherboard (ATX form factor) to
a motherboard from a 13" laptop (2008 unibody Macbook)




Inner view of a Sony Vaio laptop

The basic components of laptops are similar in function to their desktop counterparts, but
are miniaturized, adapted to mobile use, and designed for low power consumption.
Because of the additional requirements, laptop components have worse performance than
desktop parts of comparable price. Furthermore, the design bounds on power, size, and
cooling of laptops limit the maximum performance of laptop parts compared to that of
desktop components. [17]

The following list summarizes the differences and distinguishing features of laptop
components in comparison to desktop personal computer parts:

      Motherboard - laptop motherboards are highly make- and model-specific, and do
       not conform to a desktop form factor. Unlike a desktop board that usually has
       several slots for expansion cards (3 to 7 are common), a board for a small, highly
      integrated laptop may have no expansion slots at all, with all the functionality
      implemented on the motherboard itself; the only expansion possible in this case is
      via an external port such as USB. Other boards may have one or more standard or
      proprietary expansion slots. Several other functions (storage controllers,
      networking, sound card and external ports) are implemented on the
      motherboard.[18]

     Central processing unit (CPU) - Laptop CPUs have advanced power-saving
      features and produce less heat than desktop processors, but are not as powerful.[19]
      There is a wide range of CPUs designed for laptops available from Intel (Pentium
      M, Celeron M, Intel Core and Core 2 Duo), AMD (Athlon, Turion 64, and
      Sempron), VIA Technologies, Transmeta and others. On the non-x86
      architectures, Motorola and IBM produced the chips for the former PowerPC-
      based Apple laptops (iBook and PowerBook). Some laptops have removable
      CPUs, although support by the motherboard may be restricted to the specific
      models.[20] In other laptops the CPU is soldered on the motherboard and is non-
      replaceable.




A SODIMM memory module.

     Memory (RAM) - SO-DIMM memory modules that are usually found in laptops
      are about half the size of desktop DIMMs.[18] They may be accessible from the
      bottom of the laptop for ease of upgrading, or placed in locations not intended for
      user replacement such as between the keyboard and the motherboard.

     Expansion cards - A PC Card (formerly PCMCIA) or ExpressCard bay for
      expansion cards is often present on laptops to allow adding and removing
      functionality, even when the laptop is powered on. Some subsystems (such as Wi-
      Fi or a cellular modem) can be implemented as replaceable internal expansion
      cards, usually accessible under an access cover on the bottom of the laptop. Two
      popular standards for such cards are MiniPCI and its successor, the PCI Express
      Mini. [21]

     Power supply - laptops are powered by an internal rechargeable battery that is
      charged using an external power supply. The power supply can charge the battery
      and power the laptop simultaneously; when the battery is fully charged, the laptop
      continues to run on AC power. The charger adds about 400 grams (1 lb) to the
      overall "transport weight" of the notebook.
      Battery - Current laptops utilize lithium ion batteries, with more recent models
       using the new lithium polymer technology. These two technologies have largely
       replaced the older nickel metal-hydride batteries. Typical battery life for standard
       laptops is two to five hours of light-duty use, but may drop to as little as one hour
       when doing power-intensive tasks. Batteries' performance gradually decreases
       with time, leading to an eventual replacement in one to five years, depending on
       the charging and discharging pattern. This large-capacity main battery should not
       be confused with the much smaller battery nearly all computers use to run the
       real-time clock and to store the BIOS configuration in the CMOS memory when
       the computer is off.

      Video display controller - on standard laptops video controller is usually
       integrated into the chipset. This tends to limit the use of laptops for gaming and
       entertainment, two fields which have constantly escalating hardware demands[22].
       Higher-end laptops and desktop replacements in particular often come with
       dedicated graphics processors on the motherboard or as an internal expansion
       card. These mobile graphics processors are comparable in performance to
       mainstream desktop graphic accelerator boards.[23]

      Display - Most modern laptops feature 12 inch (30 cm) or larger color active
       matrix displays with resolutions of 1024×768 pixels and above. Many current
       models use screens with higher resolution than typical for desktop PCs (for
       example, the 1440×900 resolution of a 15" Macbook Pro[24] can be found on 19"
       widescreen desktop monitors).




A size comparison of 3.5" and 2.5" hard disk drives

      Removable media drives - a DVD/CD reader/writer drive is standard. CD drives
       are becoming rare, while Blu-Ray is not yet common on notebooks[25]. Many
       ultraportables and netbooks either move the removable media drive into the
       docking station or exclude it altogether.

      Internal storage - Hard disks are physically smaller—2.5 inch (60 mm) or
       1.8 inch (46 mm) —compared to desktop 3.5 inch (90 mm) drives. Some new
       laptops (usually ultraportables) employ more expensive, but faster, lighter and
       power-efficient Flash memory-based SSDs instead. Currently, 250 to 320 Gb
       sizes are common for laptop hard disks (64 to 128 Gb for SSDs).
      Input - A pointing stick, touchpad or both are used to control the position of the
       cursor on the screen, and an integrated keyboard is used for typing. External
       keyboard and mouse may be connected using USB or PS/2 (if present).

      Ports - several USB ports, an external monitor port (VGA or DVI), audio in/out,
       and an Ethernet network port are found on most laptops. Less common are legacy
       ports such as a PS/2 keyboard/mouse port, serial port or a parallel port. S-video or
       composite video ports are more common on consumer-oriented notebooks.

[edit] Docking stations

A docking station is a relatively bulky laptop accessory that contains multiple ports,
expansion slots and bays for fixed or removable drives. A laptop connects and
disconnects easily to a docking station, typically through a single large proprietary
connector. A port replicator is a simplified docking station that only provides
connections from the laptop to input/output ports. Both docking stations and port
replicators are intended to be used at a permanent working place (a desk) to offer instant
connection to multiple input/output devices and to extend a laptop's capabilities.

Docking stations became a common laptop accessory in the early 1990s. The most
common use was in a corporate computing environment where the company had
standardized on a common network card and this same card was placed into the docking
station. These stations were very large and quite expensive. As the need for additional
storage and expansion slots became less critical because of the high integration inside the
laptop, the "port replicator" has gained popularity. The port replicator was a cheaper,
often passive device that simply mated to the connectors on the back of the notebook and
allowed the user to quickly connect his laptop so that his monitor, keyboard, printer and
other devices were instantly attached. As higher speed ports such as USB and Firewire
became common, the connection of a port replicator to a laptop was accomplished by a
small cable connected to one of the USB or FireWire ports on the notebook. Wireless
Port Replicators are available as well.

A recent variant of the port replicator is the combined power/display/USB hub cable
found in the new Apple Cinema Display[26].

[edit] Standards

Some laptop components (optical drives, hard drives, memory and internal expansion
cards) are relatively standardized, and it is possible to upgrade or replace them in many
laptops as long as the new part is of the same type.[21] Subtle incompatibilities and
variations in dimensions, however, are not uncommon.[27] Depending on the
manufacturer and model, a laptop may range from having several standard, easily
customizable and upgradeable parts to a proprietary design that can't be reconfigured at
all.
In general, components other than the four categories listed above are not intended to be
replaceable, and thus rarely follow a standard. In particular, motherboards, locations of
ports, design and placement of internal components are usually make- and model-
specific. Those parts are neither interchangeable with parts from other manufacturers nor
upgradeable. If broken or damaged, they must be substituted with an exact replacement
part. The users uneducated in the relevant fields are those the most affected by
incompatibilities, especially if they attempt to connect their laptops with incompatible
hardware or power adapters.

Intel, Asus, Compal, Quanta and other laptop manufacturers have created the Common
Building Block standard for laptop parts to address some of the inefficiencies caused by
the lack of standards.

[edit] Advantages




Laptop computers are portable and can be used in many locations (Former Mexican
President, Vicente Fox).

Portability is usually the first feature mentioned in any comparison of laptops versus
desktop PCs[28]. 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:

      Getting more done - using a laptop in places where a desktop PC can't be used,
       and at times that would otherwise be wasted. For example, an office worker
       managing his e-mails during an hour-long commute by train, or a student doing
       her homework at the university coffee shop during a break between lectures.[29]

      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 stick or CDs) 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 Wi-Fi wireless networks and cellular broadband
       data services (HSDPA, EVDO and others) combined with a near-ubiquitous
       support by laptops [30] means that a laptop can have easy Internet and local
       network connectivity while remaining mobile. Wi-Fi networks and laptop
       programs are especially widespread at university campuses.[31]

Other advantages of laptops include:

      Size - laptops are smaller than standard 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 better 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 run several hours in case of a power outage and is
       not affected by short power interruptions and brownouts. A desktop PC needs a
       UPS to handle short interruptions, brownouts and spikes; achieving on-battery
       time of more than 20-30 minutes for a desktop PC requires a large and expensive
       UPS.[32]

[edit] Disadvantages
Compared to desktop PCs, laptops have disadvantages in the following fields:

[edit] Performance

While the performance of mainstream desktops and laptops is comparable, laptops are
significantly more expensive than desktop PCs at the same performance level.[33] The
upper limits of performance of laptops are a little bit lower, and "bleeding-edge" features
usually appear first in desktops and only then, as the underlying technology matures, are
adapted to laptops.

However, for Internet browsing and typical office applications, where the computer
spends the majority of its time waiting for the next user input, even netbook-class laptops
are generally fast enough.[34] Standard laptops are sufficiently powerful for high-
resolution movie playback, 3D gaming and video editing and encoding. Number-
crunching software (databases, math, engineering, financial, etc.) is the area where the
laptops are at the biggest disadvantage.

[edit] Upgradeability

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 CPU and graphics, are not intended to be
upgradeable.

The reasons for limited upgradeability are both technical and economic. There is no
industry-wide standard form factor for laptops; each major laptop manufacturer pursues
its own proprietary design and construction, with the result that laptops are difficult to
upgrade and have high repair costs. With few exceptions, laptop components can rarely
be swapped between laptops of competing manufacturers, or even between laptops from
the different product-lines of the same manufacturer.

Some upgrades can be performed by adding external devices, either USB or in expansion
card format such a PC Card: sound cards, network adapters, hard and optical drives, and
numerous other peripherals are available. But those upgrades usually impair the laptop's
portability, because they add cables and boxes to the setup and often have to be
disconnected and reconnected when the laptop is moved.

[edit] Ergonomics and health




Laptop coaster preventing heating of lap and improving laptop airflow.

Because of their small and flat keyboard and trackpad pointing devices, prolonged use of
laptops can cause RSI.[35] Usage of ergonomic keyboards and pointing devices is
recommended to prevent injury when working for long periods of time; they can be
connected to a laptop easily by USB or via a docking station. Some health standards
require ergonomic keyboards at workplaces.

The integrated screen often causes users to hunch over for a better view, which can cause
neck or spinal injuries. A larger and higher-quality external screen can be connected to
almost any laptop to alleviate that and to provide additional "screen estate" for more
productive work.

A study by State University of New York researchers found that heat generated from
laptops can raise the temperature of the scrotum, potentially putting sperm count at risk.
The small study, which included little more than two dozen men aged 13 to 35, found that
the sitting position required to balance a laptop can raise scrotum temperature by as much
as 2.1 °C (3.8 °F). Heat from the laptop itself can raise the temperature by another 0.7 °C
(1.4 °F), bringing the potential total increase to 2.8 °C (5.2 °F). However, further research
is needed to determine whether this directly affects sterility in men.[36]

A common practical solution to this problem is to place the laptop on a table or desk.
Another solution is to obtain a cooling unit for the laptop, these units are usually USB
powered consist of a hard thin plastic case housing 1, 2 or 3 cooling fans (the whole thing
is designed to sit under a laptop) which results in the laptop remaining cool to the touch,
and greatly reduces laptop heat generation. There are several companies which make
these coolers.

Heat from using a laptop on the lap can also cause skin discoloration on the thighs.[37]

[edit] Durability




A clogged heatsink on a 2.5 year old laptop.

Due to their portability, laptops are subject to more wear and physical damage than
desktops. Components such as screen hinges, latches, power jacks[38] 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. One study found that a laptop is 3 times more likely to break during the first year
of use than a desktop.[39]

Original external components are expensive (a replacement AC adapter, for example,
could cost $75); other parts are inexpensive - a power jack can cost a few dollars - but
their replacement may require extensive disassembly and reassembly of the laptop by a
technician. Other inexpensive but fragile parts often cannot be purchased separate from
larger more expensive components.[40] The repair costs of a failed motherboard or LCD
panel may exceed the value of a used laptop.

Laptops rely on extremely compact cooling systems involving a fan and heat sink that
can fail due to eventual clogging by accumulated airborne dust and debris. Most laptops
do not have any sort of removable dust collection filter over the air intake for these
cooling systems, resulting in a system that gradually runs hotter and louder as the years
pass. Eventually the laptop starts to overheat even at idle load levels. This dust is usually
stuck inside where casual cleaning and vacuuming cannot remove it. Instead, a complete
disassembly is needed to clean the laptop.

Battery life of laptops is limited; the capacity drops with time, necessitating an eventual
replacement after a few years.

[edit] Security

Being expensive, common and portable, laptops are prized targets for theft. The cost of
the stolen business or personal data and of the resulting problems (identity theft, credit
card fraud, breach of privacy laws) can be many times the value of the stolen laptop
itself. Therefore, both physical protection of laptops and the safeguarding of data
contained on them are of the highest importance.

Most laptops have a Kensington security slot which is used to tether the computer to a
desk or other immovable object with a security cable and lock. In addition to this, modern
operating systems and third-party software offer disk encryption functionality that
renders the data on the laptop's hard drive unreadable without a key or a passphrase.

[edit] Other portable computing devices
There are several categories of portable computing devices that can run on batteries but
are not usually classified as laptops: portable computers, keyboardless tablet PCs,
Internet tablets, PDAs, Ultra Mobile PCs (UMPCs) and smartphones.




The Compaq Portable
A keyboard-less tablet PC




A Palm TX PDA




A Nokia N800 Internet tablet




An OQO Ultra Mobile PC
An Apple iPhone smartphone

A Portable computer is a general-purpose computer that can be easily moved from place
to place, but cannot be used while in transit, usually because it requires some "setting-up"
and an AC power source. The most famous example is the Osborne 1. Also called a
"transportable" or a "luggable" PC.

A Tablet PC that lacks a keyboard (also known as a non-convertible Tablet PC) is shaped
like slate or a paper notebook, features a touchscreen with a stylus and handwriting
recognition software. Tablets may not be best suited for applications requiring a physical
keyboard for typing, but are otherwise capable of carrying out most tasks that an ordinary
laptop would be able to perform.

An Internet tablet is an Internet appliance in tablet form. Unlike a Tablet PC, an Internet
tablet does not have much computing power and its applications suite is limited - it can
not replace a general purpose computer. Internet tablets typically feature an MP3 and
video player, a web browser, a chat application and a picture viewer.

A Personal digital assistant (PDA) is a small, usually pocket-sized, computer with limited
functionality. It is intended to supplement and to synchronize with a desktop computer,
giving access to contacts, address book, notes, e-mail and other features.

An Ultra Mobile PC is a full-featured, PDA-sized computer running a general-purpose
operating system.

A Smart phone is a PDA with an integrated cellphone functionality. Current smartphones
have a wide range of features and installable applications.

Boundaries that separate these categories are blurry at times. For example, the OQO
UMPC is also a PDA-sized tablet PC; the Apple eMate had the clamshell form factor of a
laptop, but ran PDA software. The HP Omnibook line of laptops included some devices
small enough to be called Ultra Mobile PCs. The hardware of the Nokia 770 internet
tablet is essentially the same as that of a PDA such as the Zaurus 6000; the only reason
it's not called a PDA is that it doesn't have PIM software. On the other hand, both the 770
and the Zaurus can run some desktop Linux software, usually with modifications.

[edit] Major brands and manufacturers
         Main article: List of laptop brands and manufacturers
There is a multitude of laptop brands and                Major laptop brands
manufacturers; several major brands,
offering notebooks in various classes, are         Acer - TravelMate, Extensa, Ferrari
listed in the box to the right.                      and Aspire
                                                   Apple - MacBook, MacBook Air
The major brands usually offer good service          and MacBook Pro
and support, including well-executed               ASUS - Asus Eee, Lamborghini
documentation and driver downloads that            Compaq - Evo, Armada, LTE, and
will remain available for many years after a        Presario
particular laptop model is no longer               Dell - Inspiron, Latitude,
produced. Capitalizing on service, support          Precision,Studio, Vostro and XPS
and brand image, laptops from major brands         Gateway
are more expensive than laptops by smaller         Hewlett-Packard - HP Pavilion, HP
brands and ODMs.                                    Omnibook, HP Compaq Notebooks
                                                   Lenovo - ThinkPad, IdeaPad, and
Some brands are specializing in a particular        3000 series
class of laptops, such as gaming laptops           Panasonic - Toughbook, Satellite,
(Alienware), netbooks (EeePC) and laptops           Let's Note (Japan only) [42]
for children (OLPC).                               Samsung - SENS: M, P, Q, R and X
                                                    series
Many brands, including the major ones, do          Sony - VAIO: FJ Series, UX, TZ,
not design and do not manufacture their             NR, SZ, CR, FZ, and AR series
laptops. Instead, a small number of Original       Toshiba - Dynabook, Equium,
Design Manufacturers (ODMs) design new              Portege, Tecra, Satellite, Qosmio,
models of laptops, and the brands choose the        Libretto
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.[41] Therefore, there
often are identical models available both
from a major label and from a low-profile
ODM in-house brand.

[edit] Sales
For year 2008 it is estimated that 145.9 million notebooks were sold, and in 2009 the
number will grow to 177.7 million.[43] The third quarter of 2008 was the first time when
notebook PC shipments exceeded desktops, with 38.6 million units versus 38.5 million
units.[44]

				
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