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A laptop, also called a notebook, is a personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

 for mobile use
Mobile computing
Mobile computing is a form of human–computer interaction by which a computer is expected to be transported during normal usage. Mobile computing has three aspects: mobile communication, mobile hardware, and mobile software...

. A laptop integrates most of the typical components of a desktop computer
Desktop computer
A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

, including a display
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...

, a keyboard
Computer keyboard
In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...

, a pointing device (a touchpad
Touchpad
A touchpad is a pointing device featuring a tactile sensor, a specialized surface that can translate the motion and position of a user's fingers to a relative position on screen. Touch pads are a common feature of laptop computers, and they are also used as a substitute for a mouse where desk...

, also known as a trackpad, and/or a pointing stick
Pointing stick
The pointing stick is an isometric joystick used as a pointing device . It was invented by research scientist Ted Selker...

) and speakers into a single unit. A laptop is powered by mains electricity
Mains electricity
Mains is the general-purpose alternating current electric power supply. In the US, electric power is referred to by several names including household power, household electricity, powerline, domestic power, wall power, line power, AC power, city power, street power, and grid power...

 via an AC adapter
AC adapter
The AC adapter, AC/DC adapter or AC/DC converter is a type of external power supply, often enclosed in what looks like an over-sized AC plug. Other names include plug pack, plug-in adapter, adapter block, domestic mains adapter, line power adapter, or power adapter...

, and can be used away from an outlet using a rechargeable battery
Rechargeable battery
A rechargeable battery or storage battery is a group of one or more electrochemical cells. They are known as secondary cells because their electrochemical reactions are electrically reversible. Rechargeable batteries come in many different shapes and sizes, ranging anything from a button cell to...

.

Portable computers, originally monochrome CRT-based and developed into the modern laptops, and 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, cheaper, more powerful and as screens became larger and of better quality, laptops became very widely used for all sorts of purposes.

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
Alan Kay
Alan Curtis Kay is an American computer scientist, known for his early pioneering work on object-oriented programming and windowing graphical user interface design, and for coining the phrase, "The best way to predict the future is to invent it."He is the president of the Viewpoints Research...

 at Xerox PARC
Xerox PARC
PARC , formerly Xerox PARC, is a research and co-development company in Palo Alto, California, with a distinguished reputation for its contributions to information technology and hardware systems....

 in 1968, and described in his 1972 paper as the "Dynabook
Dynabook
The Dynabook concept, created by Alan Kay in 1968, described what is now known as a laptop computer or a tablet or slate computer with nearly eternal battery life and software aimed at giving children access to digital media...

".

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
IBM 5100
The IBM 5100 Portable Computer was a portable computer introduced in September 1975, six years before the IBM PC. It was the evolution of a prototype called the SCAMP that was developed at the IBM Palo Alto Scientific Center in 1973. In January 1978 IBM announced the IBM 5110, its larger cousin,...

, 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
Osborne 1
The Osborne 1 was the first commercially successful portable microcomputer, released on April 3, 1981 by Osborne Computer Corporation. It weighed 10.7 kg , cost USD$ 1795, and ran the then-popular CP/M 2.2 operating system...

, released in 1981, used the Zilog Z80 and weighed 23.6 pounds (10.7 kg). It had no battery, a 5 in (12.7 cm) CRT
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

 screen, and dual 5.25 in (13.3 cm) single-density floppy drives. In the same year the first laptop-sized portable computer, the Epson HX-20
Epson HX-20
The Epson HX-20 is generally regarded as the first laptop computer, announced in November 1981, although first sold widely in 1983...

, was announced. The Epson had a LCD
Liquid crystal display
A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....

 screen, a rechargeable battery, and a calculator-size printer in a 1.6 kg (3.5 lb) chassis. Both Tandy/RadioShack
RadioShack
RadioShack Corporation   is an American franchise of electronics retail stores in the United States, as well as parts of Europe, South America and Africa. As of 2008, RadioShack reported net sales and operating revenues of $4.81 billion. The headquarters of RadioShack is located in Downtown...

 and HP also produced portable computers of varying designs during this period.

The first laptops using the flip form factor appeared in the early 1980s. The Dulmont Magnum
Dulmont Magnum
The Dulmont Magnum was an early laptop computer designed and marketed by Dulmison Pty Ltd in Australia in the late 1970s and early 1980s. The Magnum was also known internationally as the Kookaburra, and was on the market from 1982 to 1986...

 was released in Australia in 1981–82, but was not marketed internationally until 1984–85. The $8,150 ($ today) GRiD Compass 1100
GRiD Compass
The Grid Compass was one of the first laptop computers when the initial model was introduced in April 1982 ....

, released in 1982, was used at NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 and by the military among others. The Gavilan SC
Gavilan SC
The Gavilan SC was an early laptop computer, and was the first ever to be marketed as a "laptop".The brainchild of Gavilan Computer Corp. founder Manuel Fernandez, the Gavilan was introduced in May, 1983, at approximately the same time as the similar Sharp PC-5000...

, 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
Touchpad
A touchpad is a pointing device featuring a tactile sensor, a specialized surface that can translate the motion and position of a user's fingers to a relative position on screen. Touch pads are a common feature of laptop computers, and they are also used as a substitute for a mouse where desk...

 (Gavilan SC
Gavilan SC
The Gavilan SC was an early laptop computer, and was the first ever to be marketed as a "laptop".The brainchild of Gavilan Computer Corp. founder Manuel Fernandez, the Gavilan was introduced in May, 1983, at approximately the same time as the similar Sharp PC-5000...

, 1983), the pointing stick (IBM ThinkPad
ThinkPad
ThinkPad is line of laptop computers originally sold by IBM but now produced by Lenovo. They are known for their boxy black design, which was modeled after a traditional Japanese lunchbox...

 700, 1992) and handwriting recognition (Linus Write-Top, 1987). Some CPUs, such as the 1990 Intel i386SL
Intel 80386
The Intel 80386, also known as the i386, or just 386, was a 32-bit microprocessor introduced by Intel in 1985. The first versions had 275,000 transistors and were used as the central processing unit of many workstations and high-end personal computers of the time...

, 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
SpeedStep
SpeedStep is a trademark for a series of dynamic frequency scaling technologies built into some Intel microprocessors that allow the clock speed of the processor to be dynamically changed by software...

 and AMD PowerNow!
PowerNow!
PowerNow! is speed throttling and power saving technology of AMD's processors used in laptops. The CPU's clock speed and VCore are automatically decreased when the computer is under low load or idle, to save battery power, reduce heat and noise...

 in some designs.

Displays reached VGA resolution by 1988 (Compaq SLT/286), 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
Read-only
In computing, read-only can mean:* Read-only memory , a type of storage media* Read-only access to files or directories in file system permissions...

 CD-ROM
CD-ROM
A CD-ROM is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback. The 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data....

 followed by writeable CD and later read-only or writeable DVD
DVD
A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....

 and Blu-Ray, became common in laptops soon in the 2000s.

Classification


The term "laptop" can refer to a number of classes of small portable computers: name="types_pcmag">


  • Full-size Laptop: A laptop large enough to accommodate a "full-size" keyboard (a keyboard with the minimum QWERTY key layout
    QWERTY
    QWERTY is the most common modern-day keyboard layout. The name comes from the first six letters appearing in the topleft letter row of the keyboard, read left to right: Q-W-E-R-T-Y. The QWERTY design is based on a layout created for the Sholes and Glidden typewriter and sold to Remington in the...

    , which is at least 13.5 keys across that are on ¾ (0.750) inch centers, plus some room on both ends for the case). 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
    ISO 216
    ISO 216 specifies international standard paper sizes used in most countries in the world today. It defines the "A" and "B" series of paper sizes, including A4, the most commonly available size...

     A4 sheet of paper (297 mm, or about 11.7 inches), and added a vertical column of keys to the right and wider screens. Can also be laid sideways when not in use.
  • 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 netbook laptops are quite small in size, CDs
    Compact Disc
    The Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...

     cannot be used in these computers.
  • Tablet PC
    Tablet computer
    A tablet computer, or simply tablet, is a complete mobile computer, larger than a mobile phone or personal digital assistant, integrated into a flat touch screen and primarily operated by touching the screen...

    : these have touch screens. There are "convertable 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, etc.)

Desktop replacement


A desktop-replacement computer is a laptop that provides all of the capabilities of a desktop computer
Desktop computer
A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

, 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. They are bulkier and not as portable as other laptops, and their operation time on batteries is typically shorter; they are intended to be used as compact and transportable alternatives to a desktop computer.

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; a few of those models have no battery.

In the early 2000s, desktops were more powerful, easier to upgrade, and much cheaper than laptops, but in later years laptops have become much cheaper and more powerful, and most peripherals are available in laptop-compatible USB versions which minimise the need for internal add-on cards. In the second half of 2008, laptops outsold desktops for the first time.

The names "Media Center Laptops" and "Gaming Laptops" are used to describe specialized notebook computers.

Subnotebook



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 when a large battery or an additional battery pack is installed. Since the introduction of netbooks, the line between subnotebooks and higher-end netbooks has been substantially blurred.

To achieve the size and weight reductions, ultraportables use 13" and smaller screens (down to 6.4"), have relatively few ports
Computer port (hardware)
In computer hardware, a port serves as an interface between the computer and other computers or peripheral devices. Physically, a port is a specialized outlet on a piece of equipment to which a plug or cable connects...

 (but in any case include two or more USB ports), employ expensive components designed for minimal size and best power efficiency, and utilize advanced materials and construction methods. Most subnotebooks achieve a further portability improvement by omitting an optical/removable media drive; in this case they may be paired with a docking station
Docking station
A Docking station or port replicator or dock provides a simplified way of “plugging-in” an electronic device such as a laptop computer to common peripherals...

 that contains the drive and optionally more ports or an additional battery.

The term "subnotebook" is reserved to laptops that run general-purpose desktop operating systems such as Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

, Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 or Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

, rather than specialized software such as Windows CE
Windows CE
Microsoft Windows CE is an operating system developed by Microsoft for embedded systems. Windows CE is a distinct operating system and kernel, rather than a trimmed-down version of desktop Windows...

, Palm OS
Palm OS
Palm OS is a mobile operating system initially developed by Palm, Inc., for personal digital assistants in 1996. Palm OS is designed for ease of use with a touchscreen-based graphical user interface. It is provided with a suite of basic applications for personal information management...

 or Internet Tablet OS.

At Computex 2011
Computex Taipei
COMPUTEX Taipei, or Taipei International Information Technology Show , is a computer expo held annually in Taipei, Taiwan. Since the early 2000s, it has become one of the largest computer and technology fairs in the world.-Development:...

 Intel announced a new class for ultraportables called ultrabook
Ultrabook
An Ultrabook is a computer in a category of thin and lightweight ultraportable laptops, defined by a specification from Intel. The name Ultrabook is an Intel trademark...

s. The term is used to describe a highly portable laptop that has strict limits for size, weight, battery life, and have tablet-like features such as instant on functionality. Intel estimates that by the end of 2012, 40 percent of the consumer laptop market segment will be Ultrabooks.

Netbook


Netbook
Netbook
Netbooks are a category of small, lightweight, legacy-free, and inexpensive laptop computers.At their inception in late 2007 as smaller notebooks optimized for low weight and low cost — netbooks omitted certain features , featured smaller screens and keyboards, and offered reduced computing...

s are laptops that are light-weight, economical, energy-efficient and especially suited for wireless communication and Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

 access. Hence the name netbook (as "the device excels in web-based computing performance").

With primary focus given to web browsing
World Wide Web
The World Wide Web is a system of interlinked hypertext documents accessed via the Internet...

 and e-mailing, netbooks are intended to "rely heavily on the Internet for remote access to web-based applications
Web application
A web application is an application that is accessed over a network such as the Internet or an intranet. The term may also mean a computer software application that is coded in a browser-supported language and reliant on a common web browser to render the application executable.Web applications are...

" and are targeted increasingly at cloud computing
Cloud computing
Cloud computing is the delivery of computing as a service rather than a product, whereby shared resources, software, and information are provided to computers and other devices as a utility over a network ....

 users who rely on servers and require a less powerful client computer
Client (computing)
A client is an application or system that accesses a service made available by a server. The server is often on another computer system, in which case the client accesses the service by way of a network....

. A common distinguishing feature is the lack of optical disk (i.e. CD, DVD or BluRay) drives. While the devices range in size from below 5 inches to over 12, most are between 9 and 11 inches (279.4 mm) and weigh between (2–3 pounds).

Netbooks are mostly sold with light-weight operating systems such as Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

, Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...

 and Windows 7 Starter edition.

Because they're very portable, Netbooks have a few disadvantages. Because the netbooks are thin, the first such products introduced to the market had their primary internal storage in the form of solid-state drive
Solid-state drive
A solid-state drive , sometimes called a solid-state disk or electronic disk, is a data storage device that uses solid-state memory to store persistent data with the intention of providing access in the same manner of a traditional block i/o hard disk drive...

s and not hard disks, which are essential to installing very many programs. Hard disk drive technology and form factors have since been adapted to fit into netbooks.

Given their size and use of more rudimentary components compared to notebooks and subnotebook
Subnotebook
A subnotebook is a class of laptop computers that are smaller and lighter than a typical laptop....

s, netbooks also generally have a smaller-capacity hard drive, slower CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

, and a lower-profile RAM capacity.

Recently, Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...

 has announced to be developing an own operating system called Chrome
Google Chrome OS
Google Chrome OS is a Linux-based operating system designed by Google to work exclusively with web applications. Google announced the operating system on July 7, 2009 and made it an open source project, called Chromium OS, that November....

 for this market.

The big breakthrough for netbook computers did not happen until the weight, diagonal form-factor and price combination of , , , respectively, became commercially available at around 2008.

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, 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 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.

Tablet laptop


Typical modern convertible laptops have a complex joint between the keyboard housing and the display permitting the display panel to swivel and then lie flat on the keyboard housing.

Typically, the base of a tablet laptop attaches to the display at a single joint called a swivel hinge or rotating hinge. The joint allows the screen to rotate through 180° and fold down on top of the keyboard to provide a flat writing surface. This design, although the most common, creates a physical point of weakness on the notebook.

Some manufacturers have attempted to overcome these weak points. The Panasonic Toughbook
Toughbook
Toughbook is a trademarked brand name owned by Panasonic Corporation and refers to its line of rugged computers. The Toughbook is designed to withstand vibration, drops, spills, extreme temperature, and other rough handling....

 19, for example, is advertised as a more durable convertible notebook. One model by Acer (the TravelMate C210) has a sliding design in which the screen slides up from the slate-like position and locks into place to provide the laptop mode.

Tablet laptops have the advantage to offer the keyboard and pointing device (usually a trackpad) of older notebooks, for users who do not use the touchscreen
Touchscreen
A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touching the display of the device with a finger or hand. Touchscreens can also sense other passive objects, such as a stylus...

 display as the primary method of input. Tablets are also touchscreen.

Components


The basic components of laptops are similar in function to their desktop counterparts, but are miniaturized
Miniaturization
Miniaturization is the creation of ever-smaller scales for mechanical, optical, and electronic products and devices...

, adapted to mobile use, and designed for low power consumption. Because of the additional requirements, laptop components are usually of inferior performance compared to similarly priced desktop parts. Furthermore, the design bounds on power, size, and cooling of laptops limit the maximum performance of laptop parts compared to that of desktop components.

The following list summarizes the differences and distinguishing features of laptop components in comparison to desktop personal computer parts:
  • Central processing unit
    Central processing unit
    The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

     (CPU): Laptop CPUs have advanced power-saving features and produce less heat than desktop processors, but are not as powerful. There is a wide range of CPUs designed for laptops available from Intel (Pentium M
    Pentium M
    The Pentium M brand refers to a family of mobile single-core x86 microprocessors introduced in March 2003 , and forming a part of the Intel Carmel notebook platform under the then new Centrino brand...

    , Celeron M, Intel Core
    Intel Core
    Yonah was the code name for Intel's first generation of 65 nm process mobile microprocessors, based on the Banias/Dothan-core Pentium M microarchitecture. SIMD performance has been improved through the addition of SSE3 instructions and improvements to SSE and SSE2 implementations, while integer...

     and Core 2 Duo), AMD (Athlon
    Athlon
    Athlon is the brand name applied to a series of x86-compatible microprocessors designed and manufactured by Advanced Micro Devices . The original Athlon was the first seventh-generation x86 processor and, in a first, retained the initial performance lead it had over Intel's competing processors...

    , Turion 64, and Sempron
    Sempron
    Sempron has been the marketing name used by AMD for several different budget desktop CPUs, using several different technologies and CPU socket formats. The Sempron replaced the AMD Duron processor and competes against Intel's Celeron series of processors...

    ), VIA Technologies
    VIA Technologies
    VIA Technologies is a Taiwanese manufacturer of integrated circuits, mainly motherboard chipsets, CPUs, and memory, and is part of the Formosa Plastics Group. It is the world's largest independent manufacturer of motherboard chipsets...

    , Transmeta
    Transmeta
    Transmeta Corporation was a US-based corporation that licensed low power semiconductor intellectual property. Transmeta originally produced very long instruction word code morphing microprocessors, with a focus on reducing power consumption in electronic devices. It was founded in 1995 by Bob...

     and others. On the non-x86 architectures, Motorola and IBM produced the chips for the former PowerPC
    PowerPC
    PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...

    -based Apple laptops (iBook
    IBook
    The iBook was a line of laptop computers sold by Apple Computer from 1999 to 2006. The line targeted the consumer and education markets, with lower specifications and prices than the PowerBook, Apple's higher-end line of laptop computers....

     and PowerBook
    PowerBook
    The PowerBook was a line of Macintosh laptop computers that was designed, manufactured and sold by Apple Computer, Inc. from 1991 to 2006. During its lifetime, the PowerBook went through several major revisions and redesigns, often being the first to incorporate features that would later become...

    ). Some laptops have removable CPUs, although support by the motherboard may be restricted to the specific models. In other laptops the CPU is soldered on the motherboard and is non-replaceable.

  • Memory (RAM): SO-DIMM
    SO-DIMM
    A SO-DIMM, or small outline dual in-line memory module, is a type of computer memory built using integrated circuits.SO-DIMMs are a smaller alternative to a DIMM, being roughly half the size of regular DIMMs...

     memory modules that are usually found in laptops are about half the size of desktop DIMM
    DIMM
    A DIMM or dual in-line memory module, comprises a series of dynamic random-access memory integrated circuits. These modules are mounted on a printed circuit board and designed for use in personal computers, workstations and servers...

    s. 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. Currently, most midrange laptops are factory equipped with 3–4 GB of DDR2
    DDR2 SDRAM
    DDR2 SDRAM is a double data rate synchronous dynamic random-access memory interface. It supersedes the original DDR SDRAM specification and has itself been superseded by DDR3 SDRAM...

     RAM, while some higher end notebooks feature up to 32 GB of DDR3 memory. Netbooks however, are commonly equipped with only 1 GB of RAM to keep manufacturing costs low.
  • Expansion cards: A PC Card
    PC Card
    In computing, PC Card is the form factor of a peripheral interface designed for laptop computers. The PC Card standard was defined and developed by the Personal Computer Memory Card International Association which itself was created by a number of computer industry companies in the United States...

     (formerly PCMCIA) or ExpressCard
    ExpressCard
    ExpressCard is an interface to allow peripheral devices to be connected to a computer, usually a laptop computer. Formerly called NEWCARD, the ExpressCard standard specifies the design of slots built into the computer and of cards which can be inserted into ExpressCard slots. The cards contain...

     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 Ethernet
    Ethernet
    Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....

    , Wi-Fi
    Wi-Fi
    Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...

    , or a cellular modem
    Wireless modem
    A wireless modem is a type of modulator-demodulator which connects to a wireless network instead of using telephone or cable television lines...

    ) 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.
  • Power supply
    Power supply
    A power supply is a device that supplies electrical energy to one or more electric loads. The term is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy to electrical energy...

    : Laptops are typically powered by an internal rechargeable battery
    Rechargeable battery
    A rechargeable battery or storage battery is a group of one or more electrochemical cells. They are known as secondary cells because their electrochemical reactions are electrically reversible. Rechargeable batteries come in many different shapes and sizes, ranging anything from a button cell to...

     that is charged using an external power supply, which outputs a DC voltage typically in the range of 7.2–14.8 volts. The power supply is usually external, and connected to the laptop through a AC connector cable. It can charge the battery and power the laptop simultaneously; when the battery is fully charged, the laptop continues to run on power supplied by the external power supply. The charger adds about 400 grams (1 lb) to the overall "transport weight" of the notebook.
  • Battery
    Battery (electricity)
    An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

    : 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. A battery's performance gradually decreases with time, leading to an eventual replacement in one to three 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
    Real-time clock
    A real-time clock is a computer clock that keeps track of the current time. Although the term often refers to the devices in personal computers, servers and embedded systems, RTCs are present in almost any electronic device which needs to keep accurate time.-Terminology:The term is used to avoid...

     and to store the BIOS
    BIOS
    In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....

     configuration in the CMOS
    CMOS
    Complementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...

     memory when the computer is off. Lithium-ion batteries do not have a memory effect as older batteries may have. The memory effect happens when one does not use a battery to its fullest extent, then recharges the battery. New innovations in laptops and batteries have seen new possible matchings which can provide up to a full 24 hours of continued operation, assuming average power consumption levels. An example of this is the HP EliteBook 6930p when used with its ultra-capacity battery.
  • Video display controller
    Video card
    A video card, Graphics Card, or Graphics adapter is an expansion card which generates output images to a display. Most video cards offer various functions such as accelerated rendering of 3D scenes and 2D graphics, MPEG-2/MPEG-4 decoding, TV output, or the ability to connect multiple monitors...

    : On standard laptops the video controller is usually integrated into the chipset
    Chipset
    A chipset, PC chipset, or chip set refers to a group of integrated circuits, or chips, that are designed to work together. They are usually marketed as a single product.- Computers :...

     to conserve power. This tends to limit the use of laptops for gaming and entertainment, two fields which have constantly escalating hardware demands, and because the integrated chipset is very difficult to upgrade for a standard user, laptops may grow obsolete quickly for use in gaming and entertainment. 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. A few notebooks have switchable graphics with both an integrated and discrete card installed. The user can choose between using integrated graphics when battery life is important and dedicated graphics when demanding applications call for it. This allows for greater flexibility and also conserves power when not required.
  • Display
    Computer display
    A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...

    : Most modern laptops feature 13 inches (33 cm) or larger color active matrix displays
    Active-matrix liquid crystal display
    An active matrix liquid crystal display is a type of flat panel display, currently the overwhelming choice of notebook computer manufacturers, due to low weight, very good image quality, wide color gamut and response time...

     based on CCFL or LED
    LEd
    LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....

     lighting with resolutions of 1280×800 (16:10) or 1366 × 768 (16:9
    16:9
    16:9 is an aspect ratio with a width of 16 units and height of 9. Since 2009, it has become the most common aspect ratio for sold televisions and computer monitors and is also the international standard format of HDTV, Full HD, non-HD digital television and analog widescreen television ...

    ) pixels and above. Some models use screens with resolutions common in desktop PCs (for example, 1440×900, 1600×900 and 1680×1050.) Models with LED-based lighting offer a lesser power consumption and wider viewing angles. Netbooks' with a 10 inches (25.4 cm) or smaller screen typically use a resolution of 1024×600, while netbooks and subnotebooks with a 11.6 inches (29.5 cm) or 12 inches (30.5 cm) screen use standard notebook resolutions.


  • Removable media
    Removable media
    In computer storage, removable media refers to storage media which is designed to be removed from the computer without powering the computer off.Some types of removable media are designed to be read by removable readers and drives...

     drives: A DVD
    DVD
    A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....

    /CD reader/writer drive is nearly universal on full-sized models, and is common on thin-and-light models; it is uncommon on subnotebooks and unknown on netbooks. CD drives are becoming rare, while Blu-Ray is becoming more common on notebooks.
  • Internal storage: Laptop hard disk
    Hard disk
    A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...

    s are physically smaller—2.5 inches (63.5 mm) or 1.8 inches (45.7 mm) —compared to desktop 3.5 inches (88.9 mm) drives. Some newer laptops (usually ultraportables) employ more expensive, but faster, lighter and power-efficient flash memory
    Flash memory
    Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...

    -based SSDs
    Solid-state drive
    A solid-state drive , sometimes called a solid-state disk or electronic disk, is a data storage device that uses solid-state memory to store persistent data with the intention of providing access in the same manner of a traditional block i/o hard disk drive...

     instead. Currently, 250 to 500 GB sizes are common for laptop hard disks (64 to 512 GB for SSDs).
  • Input: A pointing stick
    Pointing stick
    The pointing stick is an isometric joystick used as a pointing device . It was invented by research scientist Ted Selker...

    , touchpad
    Touchpad
    A touchpad is a pointing device featuring a tactile sensor, a specialized surface that can translate the motion and position of a user's fingers to a relative position on screen. Touch pads are a common feature of laptop computers, and they are also used as a substitute for a mouse where desk...

     or both are used to control the position of the cursor on the screen, and an integrated keyboard is used for typing. An external keyboard and/or mouse may be connected using USB or PS/2 port, or Bluetooth
    Bluetooth
    Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...

     (if present).
  • Ports
    Computer port (hardware)
    In computer hardware, a port serves as an interface between the computer and other computers or peripheral devices. Physically, a port is a specialized outlet on a piece of equipment to which a plug or cable connects...

    : several USB ports, an external monitor port (VGA, DVI
    Digital Visual Interface
    The Digital Visual Interface is a video interface standard covering the transmission of video between a source device and a display device. The DVI standard has achieved widespread acceptance in the PC industry, both in desktop PCs and monitors...

    , mini-DisplayPort
    DisplayPort
    DisplayPort is a digital display interface standard produced by the Video Electronics Standards Association . The specification defines a royalty-free digital interconnect for audio and video. The interface is primarily used to connect a video source to a display device such as a computer monitor...

     or HDMI
    HDMI
    HDMI is a compact audio/video interface for transmitting uncompressed digital data. It is a digital alternative to consumer analog standards, such as radio frequency coaxial cable, composite video, S-Video, SCART, component video, D-Terminal, or VGA...

    ), audio in/out, and an Ethernet
    Ethernet
    Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....

     network port are found on most laptops. Less common are legacy port
    Legacy port
    A legacy port is a computer port or connector that is considered fully or partially superseded. The replacement ports usually provide the functionality of the legacy ports with higher speeds, more compact design, or plug and play and hot swap for greater ease of use; special USB adapters are often...

    s such as a PS/2 keyboard/mouse port, serial port
    Serial port
    In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time...

     or a parallel port
    Parallel port
    A parallel port is a type of interface found on computers for connecting various peripherals. In computing, a parallel port is a parallel communication physical interface. It is also known as a printer port or Centronics port...

    . S-video
    S-Video
    Separate Video, more commonly known as S-Video and Y/C, is often referred to by JVC as both an S-VHS connector and as Super Video. It is an analog video transmission scheme, in which video information is encoded on two channels: luma and chroma...

     or composite video
    Composite video
    Composite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...

     ports are more common on consumer-oriented notebooks.
  • Cooling: Waste heat from operation is difficult to remove in the compact internal space of a laptop. Early laptops used heat sink
    Heat sink
    A heat sink is a term for a component or assembly that transfers heat generated within a solid material to a fluid medium, such as air or a liquid. Examples of heat sinks are the heat exchangers used in refrigeration and air conditioning systems and the radiator in a car...

    s placed directly on the components to be cooled, but when these hot components are deep inside the device, a large space-wasting air duct is needed to exhaust the heat. Modern laptops instead rely on heat pipe
    Heat pipe
    A heat pipe or heat pin is a heat-transfer device that combines the principles of both thermal conductivity and phase transition to efficiently manage the transfer of heat between two solid interfaces....

    s to rapidly move waste heat towards the edges of the device, to allow for a much smaller and compact fan and heat sink cooling system. Waste heat is usually exhausted away from the device operator, towards the rear or sides of the device. Multiple air intake paths are used, because some intakes can be blocked, such as when the device is placed on a soft conforming surface such as a chair cushion. Some designs with metal cases, like Apple's aluminum MacBook Pro
    MacBook Pro
    The MacBook Pro is a line of Macintosh portable computers introduced in January 2006 by Apple. It replaced the PowerBook G4 and was the second model, after the iMac, to be announced in the Apple–Intel transition...

     and MacBook Air
    MacBook Air
    The MacBook Air family is a line of Apple ultraportable Macintosh notebook computers.The first-generation MacBook Air was a 13.3"-only model, previously promoted as the World's Thinnest Notebook, introduced at the Macworld Conference & Expo on January 15, 2008. It featured a custom Intel Merom CPU...

     also employ the case of the machine as a "gigantic" heat sink, and rely on it to pump heat out of the device core. Secondary device temperature monitoring may reduce performance or trigger an emergency shutdown if it is unable to dissipate heat, such as if the laptop were to be left running and placed inside a carrying case. Such a condition has the potential to melt plastics or ignite a fire.


Docking stations


A docking station
Docking station
A Docking station or port replicator or dock provides a simplified way of “plugging-in” an electronic device such as a laptop computer to common peripherals...

 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, port replicators have gained popularity, being a cheaper, often passive device that often simply mates to the connectors on the back of the notebook, or connects via a standardized port such as USB or Fire Wire.

Standards


In general, components other than the four categories listed above are not intended to be replaceable; a few, such as processors, follow their own standards but are difficult to replace because of other factors (for example, in the case of processors cooling and access limitations can make upgrades very difficult or impossible.)

In particular, motherboards are almost always make and model-specific: locations of ports, and design and placement of internal components are not standard. Those parts are neither interchangeable with parts from other manufacturers (replaceable) nor upgradeable. If broken or damaged, they must be substituted with an exact replacement part. Those 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
ASUS
ASUSTeK Computer Incorporated is a multinational computer technology and consumer electronics product manufacturer headquartered in Taipei, Taiwan. Its product range includes motherboards, desktops, laptops, monitors, tablet PCs, servers and mobile phones...

, Compal
Compal Electronics
Compal Electronics is a Taiwanese original design manufacturer , handling the production of notebook computers, monitors, and televisions for a variety of clients around the world, including Acer Inc., Dell, Toshiba, Hewlett-Packard, and Fujitsu Siemens Computers...

, Quanta and other laptop manufacturers have created the Common Building Block
Common Building Block
Common Building Block is a set of technical standards for laptop components introduced by Intel in 2005, and adopted by some manufacturers.-Creation:...

 standard for laptop parts to address some of the inefficiencies caused by the lack of standards.

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 Wi-Fi
    Wi-Fi
    Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...

     wireless networks and cellular broadband data services (HSDPA, EVDO and others) combined with a near-ubiquitous support by laptops 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.


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
    Uninterruptible power supply
    An uninterruptible power supply, also uninterruptible power source, UPS or battery/flywheel backup, is an electrical apparatus that provides emergency power to a load when the input power source, typically mains power, fails...

     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 (excluding all-in-ones) this is divided into the desktop, keyboard, mouse, display, and optional peripherals such as speakers.

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.
The upper limits of performance of laptops remain much lower than the highest-end desktops (especially "workstation class" machines with two processor sockets), 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 relatively low-end laptops (such as Netbooks) can be fast enough for some users. As of mid-2010, at the lowest end, the cheapest netbooks—between US$200–300—remain more expensive than the lowest-end desktop computers (around US$200) only when those are priced without a screen/monitor. Once an inexpensive monitor is added, the prices are comparable.

Most higher-end laptops are sufficiently powerful for high-resolution movie playback, some 3D gaming and video editing and encoding. However, laptops processors can be disadvantaged when dealing with higher-end database, maths, engineering, financial software, virtualization, etc. Also, the top-of-the-line mobile graphics processors (GPUs) are significantly behind the top-of-the-line desktop GPUs to a greater degree than the processors, which limits the utility of laptops for high-end 3D gaming and scientific visualization applications.

Some manufacturers work around this performance problem by using desktop CPUs for laptops.

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 motherboard, CPU and graphics, are not always intended to be upgradeable. Intel, Asus
ASUS
ASUSTeK Computer Incorporated is a multinational computer technology and consumer electronics product manufacturer headquartered in Taipei, Taiwan. Its product range includes motherboards, desktops, laptops, monitors, tablet PCs, servers and mobile phones...

, Compal
Compal Electronics
Compal Electronics is a Taiwanese original design manufacturer , handling the production of notebook computers, monitors, and televisions for a variety of clients around the world, including Acer Inc., Dell, Toshiba, Hewlett-Packard, and Fujitsu Siemens Computers...

, Quanta and other laptop manufacturers have created the Common Building Block
Common Building Block
Common Building Block is a set of technical standards for laptop components introduced by Intel in 2005, and adopted by some manufacturers.-Creation:...

 standard for laptop parts to address some of the inefficiencies caused by the lack of standards.

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
Proprietary hardware
Proprietary hardware is computer hardware which is owned by the proprietor.Historically, most early computer hardware was designed as proprietary until the 1980s, when IBM PC changed this paradigm...

 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 as PC Card
PC Card
In computing, PC Card is the form factor of a peripheral interface designed for laptop computers. The PC Card standard was defined and developed by the Personal Computer Memory Card International Association which itself was created by a number of computer industry companies in the United States...

. Devices such as sound cards, network adapters, hard and optical drives, and numerous other peripherals are available, but these 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 on the move.

Wrists



Because of their small and flat keyboard and trackpad pointing devices, prolonged use of laptops can cause repetitive strain injury
Repetitive strain injury
Repetitive strain injury is an injury of the musculoskeletal and nervous systems that may be caused by...

.
Usage of separate, external ergonomic keyboard
Ergonomic keyboard
An ergonomic keyboard is a computer keyboard designed with ergonomic considerations to minimize muscle strain and a host of related problems. Typically such keyboards are constructed in a V shape, to allow right and left hands to type at a slight angle more natural to the human form.-Keyboard...

s 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.

Neck, spinal


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. An intermediate solution : stands.

Possible effect on fertility


A study by State University of New York
State University of New York
The State University of New York, abbreviated SUNY , is a system of public institutions of higher education in New York, United States. It is the largest comprehensive system of universities, colleges, and community colleges in the United States, with a total enrollment of 465,000 students, plus...

 researchers found that heat generated from laptops can raise the temperature of the lap of male users when balancing the computer on one's lap, potentially putting sperm count at risk. The study, which included roughly two dozen men aged 21 to 35, found that the sitting position required to balance a laptop can raise scrotum temperature by as much as 2.1 °C (3.78 °F). However, further research is needed to determine whether this directly affects sterility
Infertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...

 in men.

A 2010 study of 29 males published in Fertility and Sterility found that males who kept their laptops in their laps experienced scrotal hyperthermia in which their scrotal temperatures increased by up to 2 C. The resulting heat increase, which could not be offset with a laptop cushion, may increase male infertility.

A common practical solution to this problem is to place the laptop on a table or desk, or to use a book or pillow between the body and the laptop. Another solution is to obtain a cooling unit for the laptop—These units are usually USB powered and consist of a hard thin plastic case housing 1, 2 or 3 cooling fans (with the entire assembly designed to sit under the laptop in question) which results in the laptop remaining cool to the touch, and greatly reduces laptop heat buildup.

Thighs


Heat from using a laptop on the lap can also cause skin discoloration on the thighs known as "toasted skin syndrome".

Durability



Equipment wear : Due to their portability, laptops are subject to more wear and physical damage than desktops. Components such as screen hinges, latches, power jack
DC connector
A DC connector is an electrical connector for supplying direct current power. Unlike domestic AC power plugs and sockets, DC connectors are not generally standardized....

s and power cord
Power cord
A power cord, line cord, or mains cable is a cable that temporarily connects an appliance to the mains electricity supply via a wall socket or extension cord. The terms are generally used for cables using a power plug to connect to a single-phase alternating current power source at the local line...

s 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 three times more likely to break during the first year of use than a desktop.

Parts replacement : Original external components are expensive, and usually proprietary and non-interchangeable; 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. The repair costs of a failed motherboard or LCD panel often exceed the value of a used laptop.

Heat cooling : Laptops rely on extremely compact cooling systems involving a fan
Computer fan
A computer fan is any fan inside, or attached to, a computer case used for cooling purposes, and may refer to fans that draw cooler air into the case from the outside, expel warm air from inside, or move air across a heatsink to cool a particular component...

 and heat sink
Heat sink
A heat sink is a term for a component or assembly that transfers heat generated within a solid material to a fluid medium, such as air or a liquid. Examples of heat sinks are the heat exchangers used in refrigeration and air conditioning systems and the radiator in a car...

 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. Compressed air can dislodge the dust and debris but may not remove it; once the device is turned on, the loose debris is reapplied to the cooling system by the fans. Instead, a complete disassembly is needed to clean the laptop. Many laptops are difficult to disassemble by the average user and contain components sensitive to electrostatic discharge
Electrostatic discharge
Electrostatic discharge is a serious issue in solid state electronics, such as integrated circuits. Integrated circuits are made from semiconductor materials such as silicon and insulating materials such as silicon dioxide...

 (ESD).

Battery life : Battery life is limited because the capacity drops with time, necessitating an eventual replacement after a few years. 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. Yet, as it ages the battery's energy storage will progressively dissipate to last only a few minutes. The battery is often easily replaceable, and one may replace it with a higher capacity model to achieve better battery life.

Security and privacy



Because they are valuable, common, and portable, laptops are prized targets for theft
Laptop theft
Laptop theft is a significant threat to users of laptop computers. Many methods to protect the data and to prevent theft have been developed, including alarms, laptop locks, and visual deterrents such as stickers or labels. Victims of laptop theft can lose hardware, software, and essential data...

. The cost of stolen business or personal data, and of the resulting problems (identity theft
Identity theft
Identity theft is a form of stealing another person's identity in which someone pretends to be someone else by assuming that person's identity, typically in order to access resources or obtain credit and other benefits in that person's name...

, credit card fraud
Credit card fraud
Credit card fraud is a wide-ranging term for theft and fraud committed using a credit card or any similar payment mechanism as a fraudulent source of funds in a transaction. The purpose may be to obtain goods without paying, or to obtain unauthorized funds from an account. Credit card fraud is also...

, 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
Kensington Security Slot
A Kensington Security Slot is part of an anti-theft system designed by Kensington Computer Products Group,Ltd....

, 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
Disk encryption software
To protect confidentiality of the data stored on a computer disk a computer security technique called disk encryption is used. This article discusses software that is used to implement the technique...

 offer disk encryption
Disk encryption
Disk encryption is a special case of data at rest protection when the storage media is a sector-addressable device . This article presents cryptographic aspects of the problem...

 functionality, which renders the data on the laptop's hard drive unreadable without a key
Key (cryptography)
In cryptography, a key is a piece of information that determines the functional output of a cryptographic algorithm or cipher. Without a key, the algorithm would produce no useful result. In encryption, a key specifies the particular transformation of plaintext into ciphertext, or vice versa...

 or a pass phrase. Some laptops also now have additional security elements added by the consumer, including eye recognition software and fingerprint scanning components.

In Robbins v. Lower Merion School District (Eastern District of Pennsylvania 2010), school-issued laptops loaded with special software afforded two high schools with the capability to take secret webcam shots of their students at home, via their students' laptops.

Major brands and manufacturers


There is a multitude of laptop brands and manufacturers; several major brands, offering notebooks in various classes, are listed in the box to the right.

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
Original Design Manufacturer
An original design manufacturer is a company which designs and manufactures a product which is specified and eventually branded by another firm for sale. Such companies allow the brand firm to produce without having to engage in the organization or running of a factory...

.

Some brands are specializing in a particular class of laptops, such as gaming laptops (Alienware
Alienware
Alienware is an American computer hardware subsidary of Dell, Inc. It mainly assembles third party components into desktops and laptops with custom enclosures for high-performance gaming. These products also support graphically intense applications such as video editing, simulation, and audio editing...

), selling high-performance laptops (Hp Envy
HP Envy
The HP ENVY series is a line of high performance laptops manufactured and sold by Hewlett-Packard, which was launched on October 15, 2009 as two models, the Envy 13 and the Envy 15...

), netbooks (EeePC) and laptops for children (OLPC).

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. Therefore, there often are identical models available both from a major label and from a low-profile ODM in-house brand.

Sales


Battery-powered portable computers had just 2% worldwide market share in 1986. However, laptops have become increasingly popular, both for business and personal use.
Around 109 million notebook PCs shipped worldwide in 2007, a growth of 33% compared to 2006.
In 2008 it was estimated that 145.9 million notebooks were sold, and that the number would grow in 2009 to 177.7 million. The third quarter of 2008 was the first time when notebook PC shipments exceeded desktops
Desktop computer
A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

, with 38.6 million units versus 38.5 million units.

For Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 systems, the average selling price (ASP) showed a decline in 2008/2009, possibly due to low-cost netbook
Netbook
Netbooks are a category of small, lightweight, legacy-free, and inexpensive laptop computers.At their inception in late 2007 as smaller notebooks optimized for low weight and low cost — netbooks omitted certain features , featured smaller screens and keyboards, and offered reduced computing...

s, drawing US$689 at U.S. retail in August 2008. In 2009, ASP had further fallen to $602 by January and to $560 in February. While Windows machines fell $129 in these seven months, Mac
Macintosh
The Macintosh , or Mac, is a series of several lines of personal computers designed, developed, and marketed by Apple Inc. The first Macintosh was introduced by Apple's then-chairman Steve Jobs on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a...

 laptop ASP declined just $12 from $1,524 to $1,512.

Extreme environments



The ruggedized Grid Compass
GRiD Compass
The Grid Compass was one of the first laptop computers when the initial model was introduced in April 1982 ....

 computer was used since the early days of the Space Shuttle program. The first commercial
Commercial off-the-shelf
In the United States, Commercially available Off-The-Shelf is a Federal Acquisition Regulation term defining a nondevelopmental item of supply that is both commercial and sold in substantial quantities in the commercial marketplace, and that can be procured or utilized under government contract...

 laptop used in space was a Macintosh portable
Macintosh Portable
The Macintosh Portable was Apple Inc.'s first attempt at making a battery-powered portable Macintosh personal computer that held the power of a desktop Macintosh...

 in 1991 aboard Space Shuttle mission STS-43
STS-43
-Mission parameters:*Mass:**Orbiter landing with payload: **Payload: *Perigee: *Apogee: *Inclination: 28.5°*Period: 90.6 min-Preparations and Launch:The launch took place on 2 August 1991, 11:01:59 am EDT...

. Mac and other laptop computers continue to be flown aboard manned spaceflights though the only long duration flight certified computer for the International Space Station is the ThinkPad. As of 2011 over 100 ThinkPads were aboard the ISS. Laptops used aboard the International Space Station and other spaceflights are generally the same ones that can be can be purchased
Commercial off-the-shelf
In the United States, Commercially available Off-The-Shelf is a Federal Acquisition Regulation term defining a nondevelopmental item of supply that is both commercial and sold in substantial quantities in the commercial marketplace, and that can be procured or utilized under government contract...

 by the general public but needed modifications are made to allow them to be used safely and effectively in a weightless environment such as updating the cooling systems to function without relying on hot air rising and accommodation for the lower cabin air pressure.

Laptops operating in harsh usage environments and conditions, such as strong vibrations, extreme temperatures and wet or dusty condition differ from those used in space in that they are custom designed
Rugged computer
A rugged computer is a computer specifically designed to reliably operate in harsh usage environments and conditions, such as strong vibrations, extreme temperatures and wet or dusty conditions...

 for the task and do not use commercial off-the-shelf
Commercial off-the-shelf
In the United States, Commercially available Off-The-Shelf is a Federal Acquisition Regulation term defining a nondevelopmental item of supply that is both commercial and sold in substantial quantities in the commercial marketplace, and that can be procured or utilized under government contract...

 hardware.

Accessories


A common accessory for laptops is a laptop sleeve or laptop case, which provides a degree of protection from drops or impacts. Sleeves, which are distinguished by being relatively thin and flexible, are most commonly made of neoprene
Neoprene
Neoprene or polychloroprene is a family of synthetic rubbers that are produced by polymerization of chloroprene. Neoprene in general has good chemical stability, and maintains flexibility over a wide temperature range...

, with sturdier ones made of LRPu
LRPu
LRPu or low-resilience polyurethane is a material distinguished by an "ability to slowly return to its original shape" .The resulting impact resistance results in LRPu being used in soft laptop sleeves and other lightweight cases for portable electronic equipment, as an alternative to the softer...

 (low-resilience polyurethane), with some wrapped in ballistic nylon
Ballistic nylon
Ballistic nylon is a thick, tough, synthetic nylon fabric used for a variety of applications. Ballistic nylon was originally developed by the DuPont corporation as a material for flak jackets to be worn by World War II airmen...

 to provide some measure of waterproofing
Waterproofing
Waterproof or water-resistant describes objects relatively unaffected by water or resisting the ingress of water under specified conditions. Such items may be used in wet environments or under water to specified depths...

. Bulkier and sturdier cases can be made of metal with polyurethane padding inside, and may have locks, for added security.

Another common accessory is a laptop cooler
Laptop cooler
A laptop/notebook cooler, cooler pad or chill mat is an accessory for laptop computers that helps reduce their operating temperature. Normally used when the laptop's fan device is unable to sufficiently cool the laptop, a cooling pad may house active or passive cooling methods and rests beneath the...

. This device helps lower the internal temperature of the laptop by using either active or passive methods. A general active method is plugging a laptop cooler into the laptop and using fans to draw heat away from the laptop. A common passive method is just propping the laptop up on some type of pad so it can receive more air flow.

See also



  • Desktop computer
    Desktop computer
    A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

  • Handheld PC
    Handheld PC
    A Handheld PC, or H/PC for short, is a term for a computer built around a form factor which is smaller than any standard laptop computer. It is sometimes referred to as a Palmtop. The first handheld device compatible with desktop IBM personal computers of the time was the Atari Portfolio of 1989...

  • List of computer size categories
  • List of laptop brands and manufacturers
  • List of NO-OS and Open Source Laptop Manufacturers
  • Mobile broadband
    Mobile Broadband
    Mobile broadband is the marketing term for wireless Internet access through a portable modem, mobile phone or other mobile device.-Description:...

  • Mobile Internet device (MID)
  • Mobile modem
  • Mobile phone
    Mobile phone
    A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...

  • Mobility factor
    Mobility factor
    The Mobility Factor is both a standard and a performance indicator in the information technology industry, and is used to evaluate mobile performance characteristics in notebooks....

  • NEC UltraLite
    NEC UltraLite
    The NEC UltraLite was an MS-DOS-based portable computer in a "notebook" size.The product was originally developed by an NEC Japan telecommunications engineering team that was trying to make an inexpensive lightweight terminal for programming PABX systems...

  • Netbook
    Netbook
    Netbooks are a category of small, lightweight, legacy-free, and inexpensive laptop computers.At their inception in late 2007 as smaller notebooks optimized for low weight and low cost — netbooks omitted certain features , featured smaller screens and keyboards, and offered reduced computing...

  • Personal computer
    Personal computer
    A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

  • Personal digital assistant
    Personal digital assistant
    A personal digital assistant , also known as a palmtop computer, or personal data assistant, is a mobile device that functions as a personal information manager. Current PDAs often have the ability to connect to the Internet...

  • Prepaid mobile phone
  • Scissor-switch
  • Smartbook
    Smartbook
    A smartbook was a class of mobile device that combined certain features of both a smartphone and netbook computer, promoted in 2009 and 2010....

  • Smartphone
    Smartphone
    A smartphone is a high-end mobile phone built on a mobile computing platform, with more advanced computing ability and connectivity than a contemporary feature phone. The first smartphones were devices that mainly combined the functions of a personal digital assistant and a mobile phone or camera...

  • Stereoscopy
    Stereoscopy
    Stereoscopy refers to a technique for creating or enhancing the illusion of depth in an image by presenting two offset images separately to the left and right eye of the viewer. Both of these 2-D offset images are then combined in the brain to give the perception of 3-D depth...

     glasses
  • Subscriber Identity Module
    Subscriber Identity Module
    A subscriber identity module or subscriber identification module is an integrated circuit that securely stores the International Mobile Subscriber Identity and the related key used to identify and authenticate subscriber on mobile telephony devices .A SIM is held on a removable SIM card, which...

  • Tablet computer
    Tablet computer
    A tablet computer, or simply tablet, is a complete mobile computer, larger than a mobile phone or personal digital assistant, integrated into a flat touch screen and primarily operated by touching the screen...

  • Microsoft Tablet PC
    Microsoft Tablet PC
    A Microsoft Tablet PC is a term coined by Microsoft for tablet computers conforming to a set of specifications announced in 2001 by Microsoft, for a pen-enabled personal computer, conforming to hardware specifications devised by Microsoft and running a licensed copy of Windows XP Tablet PC Edition...

  • Tethering
  • Touchscreen
    Touchscreen
    A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touching the display of the device with a finger or hand. Touchscreens can also sense other passive objects, such as a stylus...

  • Ultra-Mobile PC
    Ultra-Mobile PC
    An ultra-mobile PC is a small form factor version of a pen computer, a class of laptop whose specifications were launched by Microsoft and Intel in spring 2006. Sony had already made a first attempt in this direction in 2004 with its Vaio U series, which was however only sold in Asia...