This document provides information about laptop computers. It discusses the components and history of laptops. Some key points: - Laptops have similar components to desktops but are miniaturized into a portable form factor with a screen, keyboard, trackpad, and battery power. - Early portable computers were large and heavy. Alan Kay first envisioned portable personal computers in 1968. The IBM 5100 in 1975 was one of the first commercially available portable computers. - Modern laptops come in different sizes from large full-size laptops to smaller netbooks and tablets. They can also have different features like touchscreens or ruggedized designs. - Components are smaller versions of desktop parts like CPUs,

1. EN.R.-
CIVIL-B 2013-14
LAPTOP

2. A modern Acer laptop with an 18.4" screen.
A is a portable personal computer with a clamshell form factor,
suitable for mobile use. A laptop has most of the same components as a
desktop computer, including a display, a keyboard, a pointing device such as a
touchpad (also known as a trackpad) and/or a pointing stick, and speakers into
a single unit. A laptop is powered by mains electricity via an AC adapter, and
can be used away from an outlet using a rechargeable battery. Laptops are
also sometimes called notebook computers or notebooks. Other terms, such as
ultrabooks or net books, refer to specific types of laptop / notebook. Most of
the modern day laptop computers also have a webcam and a mic (microphone)
pre-installed.

3. Portable computers, originally monochrome CRT-based and developed
into the modern laptops, 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, and more powerful and as screens became smaller and of
better quality, laptops became very widely used for a variety of purposes.
 History
Alan Kay with "Dynabook" prototype (5 November 2008 in Mountain View,
California)
As the personal computer (PC) became feasible in the 1970s, the idea of a
portable personal computer followed. A "personal, portable information
manipulator" was imagined by Alan Kay at Xerox PARC in 1968, and described in his
1972 paper as the "Dynabook".
The IBM Special Computer APL Machine Portable (SCAMP), was
demonstrated in 1973. This prototype was based on the IBM PALM processor (Put
All Logic in Microcode or 128 bit).
The IBM 5100, the first commercially available portable computer, appeared
in September 1975, and was based on the SCAMP prototype.
As 8-bit CPU machines became widely accepted, the number of portables
increased rapidly. The Osborne 1, released in 1981, used the Zilog Z80 and weighed
23.6 pounds (10.7 kg). It had no battery, a 5 in (13 cm) CRT 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, was announced.The Epson had a LCD
screen, a rechargeable battery, and a calculator-size printer in a 1.6 kg (3.5 lb)
chassis. Both Tandy/RadioShack and HP also produced portable computers of
varying designs during this period.

4. The Epson HX-20
The first laptops using the flip form factor appeared in the early 1980s. The
Dulmont Magnum was released in Australia in 1981–82, but was not marketed
internationally until 1984–85. The US$8,150 (US$19,710 today) GRiD
Compass 1100, released in 1982, was used at NASA and by the military
among others. The Gavilan SC, released in 1983, was the first computer
described as a "laptop" by its manufacturer.[8]
From 1983 onward, several new
input techniques were developed and included in laptops, including the touchpad
(Gavilan SC, 1983), the pointing stick (IBM ThinkPad 700, 1992) and
handwriting recognition (Linus Write-Top, 1987). Some CPUs, such as the
1990 Intel i386SL, were designed to use minimum power to increase battery
life of portable computers, and were supported by dynamic power management
features such as Intel SpeedStep and AMD PowerNow! in some designs.
Displays reached VGA resolution by 1988 (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 CD-ROM
followed by writeable CD and later read-only or writeable DVD and Blu-ray, became
common in laptops early in the 2000s.

5.  Classification
The MacBook Air
The term "laptop" can refer to a number of classes of small portable computers
Full-size Laptop: A laptop large enough to accommodate a "full-size" keyboard
(a keyboard with the minimum QWERTY key layout, 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 A4 sheet of paper
(297 mm, or about 11.7 inches), and added a vertical column of keys to the right
and wider screens. It can also be laid sideways when not in use.
Netbook: A smaller, lighter, and therefore more portable laptop with less
computing power than traditional laptops. It is usually cheaper than a full-size
laptop, and has fewer features. The smaller keyboards of a netbook can be more
difficult to operate. There is no definitive demarcation between net books and
inexpensive small laptops, some 11.6" models are marketed as net books. Since
netbook laptops are quite small in size and designed to be light and inexpensive
they typically do not come with an internal optical drive. The Asus Eee PC launched
this product class, while the term was coined later by Intel.

6. Most net books feature cheaper, slower, but more energy efficient CPUs,
as compared to traditional laptops, such as the Intel Atom CPU.
Tablet PC: These have touch screens. There are "convertible
tablets" with a full keyboard where the screen rotates to be used atop the
keyboard, a "hybrid tablet" where the keyboard can be detached from the
screen, 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.)
 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. Other early models were the Poqet PC of 1989 and
the Hewlett Packard HP 95LX of 1991. Other DOS compatible hand-held
computers also existed.
 Rugged: Engineered to operate in tough conditions (mechanical shocks,
extreme temperatures, wet and dusty environments, etc.)
 Ultrabook: A very thin version of a laptop by definition less than 0.8
inches thick. Most versions of Ultrabooks contain SSD, or Solid-State Drives,
instead of the common Laptop Hard
A desktop-replacement computer is a laptop that
provides all of the capabilities of a desktop computer, with a similar level of
performance. Desktop replacements are usually larger and heavier than
standard laptops. They contain more powerful components and have a 15" or
larger display.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.

7. 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 than before, and most
peripherals are available in laptop-compatible USB versions which minimize the
need for internal add-on cards.
Sony VAIO P series subnotebook
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 net books, the line
between subnotebooks and higher-end net books has been substantially blurred.
The term "subnotebook" is 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, iOS, Palm OS or
Internet Tablet OS.

8. At Computex 2011 Intel announced a new class for ultraportables called
Ultrabooks. 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
 A Samsung Chromebook.
Netbooks are laptops that are inexpensive, light-weight, economical, energy-
efficient and especially suited for wireless communication and Internet access.
Hence the name netbook (as "the device excels in web-based computing
performance").
With primary focus given to web browsing and e-mailing, net books
are intended to "rely heavily on the Internet for remote access to web-based
applications" and are targeted increasingly at cloud computing users who rely
on servers and require a less powerful client computer. A common
distinguishing feature is the lack of optical disk (i.e. CD, DVD or Blu-ray)
drives. While the devices range in size from below 5 inches to over 12 inches,
most are between 9 and 11 inches (280 mm) and weigh between 0.9–1.4 kg
(2–3 pounds).
Netbooks are mostly sold with light-weight operating systems such
as Linux, Windows XP and Windows 7 Starter edition.

9. Netbooks do have a few disadvantages. Because the net books are so thin,
the first products introduced to the market utilized solid-state drives for internal
storage instead of traditional hard disks, increasing cost and lowering storage
space. Hard disk drive technology and form factors have since been adapted to fit
into net books providing more hard drive space without increasing cost, a key point
of a netbook. Another issue with net books is expansion. In order to produce small,
inexpensive laptops, net books generally lack significant upgrade ability. A majority
of net books only have a single memory slot and will not recognize any amount
beyond 2 GB of RAM. This limits the capabilities of the netbook beyond basic
functionality (internet, e-mail, etc.). Finally because of their size and use of more
rudimentary components compared to notebooks and subnotebooks, net books also
generally have a slower CPU
In 2009, Google announced an operating system called Google
Chrome OS for this market and in 2011 the Google Chromebook was released
running on the Google Chrome OS.
The big breakthrough for netbook computers did not happen until the
weight, diagonal form-factor and price combination of < 1 kg, < 9", < U.S. $400,
respectively, became commercially available in around 2008.
Rugged laptop

10. A Panasonic Toughbook.
A rugged/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 laptops 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.
Convertible laptop
A tablet laptop with stylus

11. 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. Tablet laptops also contain touchscreen
displays alongside the traditional touchpad.
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 laptop.
Some manufacturers have attempted to overcome these weak points by
adopting innovative methods such as a sliding design in which the screen slides up
from the slate-like position and locks into place to provide the laptop mode. Newer
iterations of tablet laptops are of hybrid design. Hybrid tablets incorporate a
removable keyboard base allowing the user to easily choose between functioning as
a laptop with the keyboard attached or as a slate device utilizing the touchscreen
alone.
Components
Miniaturization: a comparison of a desktop computer motherboard (ATX
form factor) to a motherboard from a 13" laptop (2008 unibody Macbook)

12.  Inner view of a Sony VAIO laptop
The basic components of laptops function similarly to their desktop
counterparts, but are miniaturized, adapted to mobile use. 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 (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, Celeron M, Intel Core, Core 2 Duo, solo, and quad) and Intel Atom; AMD
(Athlon, Turin 64, and Semipro); VIA Technologies, Transmute and others. On non-
x86 architectures, Motorola and IBM produced the chips for the former PowerPC-
based Apple laptops (iBook and PowerBook). Most laptops have removable CPUs,
although the motherboard may restrict the processor to the specific models,
limiting the processors that are compatible. Some laptops use a desktop processor
instead of the laptop version and have high performance gains at the cost of the
potential for overheating problems, and less battery life. In other laptops the CPU
is soldered on the motherboard and is non-replaceable.

13. A SODIMM memory module
Memory (RAM): SO-DIMM memory modules that are usually found in
laptops are about half the size of desktop DIMMs. 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 mid-range laptops are factory equipped with 3–
4 GB of DDR2 RAM, while some higher end notebooks (usually mobile
engineering workstations) feature up to 32 GB of DDR3 memory. Netbooks are
commonly equipped with only 1 GB of RAM and generally only expandable to 2
GB, if at all, to keep manufacturing costs low.
Expansion cards: A PC Card (formerly PCMCIA) or Express Card bay for
expansion cards is often present on laptops to allow adding and removing
functionality, even when the laptop is powered on. Some internal subsystems
such as: Ethernet, Wi-Fi, or a Wireless 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
Menisci and its successor, the PCI Express Mini. In newer laptops it is not
uncommon to also see a Mini SATA (mSATA) connection in addition to MiniPCI
and PCI Express Mini.

14.  Power supply: Laptops are typically powered by an internal
rechargeable battery that is charged using an external power supply,
which outputs a DC voltage typically in the range of 7.2– 24 volts. The
power supply is usually external, and connected to the laptop through an
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: 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 or less 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 and to store the BIOS configuration in CMOS 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. Innovations in laptops and
batteries have seen situations which the battery can provide up to 24 hours of
continued operation, assuming average power consumption levels. An example is
the HP EliteBook 6930p when used with its ultra-capacity battery.

15. Video display controller: On standard laptops the video controller is
usually integrated into the chipset to conserve power. This tends to limit the
use of laptops for gaming and entertainment. These two fields have constantly
escalated 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 low-end 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: Most modern laptops feature 13 inches (33 cm) or larger
color active matrix displays based on CCFL or LED lighting with resolutions of
1280×800 (16:10) or 1366 × 768 (16:9) 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 lesser
power consumption, and often higher brightness. Netbooks with a 10 inches
(25 cm) or smaller screen typically use a resolution of 1024×600, while net
books and subnotebooks with a 11.6 inches (29 cm) or 12 inches (30 cm)
screen use standard notebook resolutions. Having a higher resolution display
will allow more items to fit onscreen at a time, improving the user's ability to
multitask

16. Laptops commonly use 2.5" hard disk drives, which are much smaller than
desktop hard drives.
Removable media drives: A DVD/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 net books. CD drives are becoming rare, while Blu-
ray is becoming more common on notebooks.
Internal storage: Laptop hard disks are physically smaller—2.5 inches
(64 mm) or 1.8 inches (46 mm) —compared to desktop 3.5 inches (89 mm) drives.
Some newer laptops (usually ultraportables) employ more expensive, but faster,
lighter and power-efficient flash memory-based SSDs instead. Currently, 250 to
500 GB sizes are common for laptop hard disks (64 to 512 GB for SSDs).
Ports: several USB ports, an external monitor port (VGA, DVI, mini-
DisplayPort or HDMI), 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.
Cooling: Waste heat from operation is difficult to remove in the compact
internal space of a laptop. Early laptops used heat sinks 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 pipes 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 since some
intakes can be blocked, such as when the device is placed on a soft conforming
surface like a chair cushion. It is believed that some designs with metal cases, like
Apple's aluminum MacBook Pro and MacBook Air, also employ the case of the
machine as a "gigantic" heat sink, allowing it to supplement cooling by dissipating
heat out of the device core.

17. 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 is a 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 FireWire.
Charging stations
Laptop charging trolleys, also known as laptop trolleys or laptop
carts, are mobile storage containers to charge laptops, net books and tablet
computers all together. The trolleys are predominantly used in schools that
have replaced their traditional static ICT suites of desktop computers with
laptops, but do not have enough plug sockets in their buildings to charge all of
the devices.

18. The trolleys can be wheeled between rooms and classrooms so that
anyone in a particular building can access fully charged IT equipment. Laptop
charging trolleys are also used to deter and protect against opportunistic and
organized theft. Schools, especially those with open plan designs, are often
prime targets for thieves and laptops, net books and tablets can easily be
concealed and removed from buildings. Laptop charging trolleys were designed
and constructed to protect against theft. They are generally made out of
steel, and the laptops remain locked up while not in use. Although the trolleys
can be moved between areas in buildings, they can often also be mounted to
the floor or walls to prevent thieves walking off with investments, especially
overnight.
Solar panels
In some laptops, solar panels are able to generate enough solar
power for the laptop to operate. The One Laptop Per Child Initiative released the
OLPC XO-1 laptop which was tested and successfully operated by use of solar
panels.[36]
Presently, they are designing a OLPC XO-3 laptop with these features.
The OLPC XO-3 can operate with 2 Watts of electricity because its renewable
energy resources generate a total of 4 Watts. Samsung has also designed a
NC215S Solar powered notebook that will be sold commercially in the US market.
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.

19. 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, Compal, Quanta and some 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.
Advantages

20. Portability is usually the first feature mentioned in any comparison of
laptops versus desktop PCs. Physical portability allows 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.

21. 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 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.)

22. Quiet: Laptops are often quieter than desktops, due both to the
components (quieter, slower 2.5-inch hard drives) and to less heat production
leading to use of fewer and slower cooling fans.
Battery: a charged laptop can continue to be used in case of a power outage
and is not affected by short power interruptions and blackouts. A desktop PC
needs a UPS to handle short interruptions, blackouts and spikes; achieving on-
battery time of more than 20–30 minutes for a desktop PC requires a large and
expensive UPS.
All-in-One: designed to be portable, laptops have everything integrated into
the chassis. For desktops (excluding all-in-ones) this is divided into the desktop,
keyboard, mouse, display, and optional peripherals such as speakers.
Disadvantages
Compared to desktop PCs, laptops have disadvantages in the following
areas:
While the performance of mainstream desktops and laptop is comparable,
and the cost of laptops has fallen less 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.
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 net books—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.

23. Most higher-end laptops are sufficiently powerful for high-resolution
movie playback, some 3D gaming and video editing and encoding. However, laptop
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.
 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, Compal, Quanta and some 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.
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 as PC Card. 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.

24.  Ergonomics and health effects
 Wrists
Laptop cooler (silver) under laptop (white), preventing heating of lap and
improving laptop airflow
repetitive strain injury. Usage of separate, external 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 requires users to lean over for a better view,
which can cause neck and/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 space for more productive work. Another solution is to use a
computer stand.
For anyone not buying a new screen, a simple method to reduce risk of
spinal injury is to position the laptop's screen in a manner that an obtuse angle
(more than 90 degrees open) is formed. It is then possible for the neck to remain
straight during use of the device.

25.  Possible effect on fertility
A study by State University of New York researchers found that heat
generated from laptops can increase the temperature of the lap of male users
when balancing the computer on their lap, potentially putting sperm count at risk.
The study, which included roughly two dozen men between the ages of 21 and 35,
found that the sitting position required to balance a laptop can increase scrotum
temperature by as much as 2.1 °C (3.78 °F). However, further research is needed
to determine whether this directly affects male sterility.
A 2010 study of 29 males published in Fertility and Sterility found that
men who kept their laptops on their laps experienced scrotal hyperthermia
(overheating) in which their scrotal temperatures increased by up to 2 °C. The
resulting heat increase, which could not be offset by 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 are usually USB powered
and consist of a hard thin plastic case housing one, two or three 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.
Equipment wears
Because of their portability, laptops are subject to more wear and physical
damage than desktops. Components such as screen hinges, latches, power jacks and
power cords deteriorate gradually from 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.

26. 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.
 Heating and cooling
Laptops rely on extremely compact cooling systems involving a fan
and heat sink that can fail from blockage caused by accumulated airborne dust
and debris. Most laptops do not have any type of removable dust collection
filter over the air intake for these cooling systems, resulting in a system that
gradually causes it to conduct more heat and noise as the years pass. In some
cases the laptop starts to overheat even at idle load levels. This dust is
usually stuck inside, where the fan and heat sink meet, where casual cleaning
and vacuuming cannot remove it.
Compressed air can dislodge the dust and debris but may not always
remove it; after the device is turned on, the loose debris builds back up the cooling
system by the fans. A complete dis-assembly is usually required to clean the
laptop. Many laptops are difficult to disassemble by the normal user and contain
components that are sensitive to electrostatic discharge .
Battery life
Battery life is limited because the capacity drops with time, eventually
requiring replacement after as little as a year. A new battery typically stores
enough energy to run the laptop for three to five hours, depending on usage,
configuration, and power management settings. Yet, as it ages, the battery's
energy storage will dissipate progressively until it lasts only a few minutes. The
battery is often easily replaceable and a higher capacity model may be obtained
for longer life

27. Security and privacy
Because they are valuable, common, and portable, laptops are prized targets
for theft. Every day, over 1,600 laptops go missing - and that's only from U.S.
airports.[62]
The cost of stolen business or personal data, and of the resulting
problems (identity theft, credit card fraud, breach of privacy), can be many times
the value of the stolen laptop itself. Consequently, physical protection of laptops
and the safeguarding of data contained on them are both of great importance.
Most laptops have a Kensington security slot, which can be used to tether
them to a desk or other immovable object with a security cable and lock. In
addition, modern operating systems and third-party software offer disk
encryption functionality, which renders the data on the laptop's hard drive
unreadable without a key or a pass phrase. Some laptops also now have additional
security elements added by the consumer, including eye recognition software and
fingerprint scanning components. Software such as LoJack for Laptops, Laptop
Cop, and GadgetTrack have been engineered to help victims locate and recover a
laptop in the event of theft.

28. 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.
 Laptop Theft Recovery
Laptop theft is a serious problem, with less than 5% of lost or stolen laptops ever
recovered by the companies that own them. However, that number may decrease
due to a variety of companies and software solutions specializing in laptop
recovery. For example, LoJack for Laptops is security software that includes an
Investigations and Theft Recovery Team made up of ex law enforcement officers
who locate and recover stolen laptops. The service utilizes persistent technology,
which means it can't be removed or disabled by a thief. LoJack can only work to
track down a missing laptop when it is turned on and it is connected to the
Internet. The owner can also remotely delete files or lock their device, so no one
can access their personal data.
Major brands and manufacturers
The Sony Vaio brand is among the best selling laptops.

29. There are a multitude of laptop brands and manufacturers; several
major brands, offering note
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.
Some brands are specializing in a particular class of laptops, such as
gaming laptops (Alienware), high-performance laptops (HP Envy), net books (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%
of 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 worldwide notebook PC
shipments exceeded desktops, with 38.6 million units versus 38.5 million units.
THE END.