Laptop
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, more powerful and as screens became larger and of better quality, laptops became very widely used for all sorts of purposes.
Classification
- 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.[12] The first laptops were the size of a standard U.S. "A size" notebook sheet of paper (8.5 × 11 inches)[citation needed], 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, more portable laptop. It is also usually cheaper than a full-size laptop, but sometimes 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, netbooks 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.
- Tablet PC: 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.)
- Ultra-mobile PC: An ultra-mobile PC (ultra-mobile personal computer or UMPC) 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. UMPCs are smaller than subnotebooks, have a TFT display measuring (diagonally) about 12.7 to 17.8 cm, and are operated like tablet PCs using a touchscreen or a stylus. This term is commonly (if inaccurately) used for small notebooks and/or netbooks.
- 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. Another early model was 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 usually less than an inch thick. Most versions of Ultrabooks contain SSD, or Solid-State Drives, instead of the common Laptop Hard Disk Drives. Although this term (like Netbook) was coined and popularised by Intel, one of the most prominent examples is Apple's Macbook Air.
Desktop replacement
Main article: Desktop replacement computer
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.[11]
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.[11]Some laptops in this class use a limited range of desktop components to provide better performance for the same price at the expense of battery life; a few of those models have no battery.[13] 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,[14] and most peripherals are available in laptop-compatible USB versions which minimise the need for internal add-on cards.
The names "Media Center Laptops" and "Gaming Laptops" are used to describe specialized notebook computers.[10]
Subnotebook
Main article: 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);[10] the battery life can exceed 10 hours[15]
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 (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 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, Linux or Mac OS X, rather than specialized software such as Windows CE, Palm OS or Internet Tablet OS.
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.[16]
[edit]Main article: Netbook
Netbooks are laptops that are light-weight, economical, energy-efficient and especially suited for wireless communication and Internet access.[17][18] Hence the name netbook (as "the device excels in web-based computing performance").[19]With primary focus given to web browsing and e-mailing, netbooks are intended to "rely heavily on the Internet for remote access to web-based applications"[19] and are targeted increasingly at cloud computing users who rely on servers and require a less powerful client computer.[20] 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[21] to over 12,[22] most are between 9 and 11 inches (280 mm) and weigh between 0.9–1.4 kg (2–3 pounds).[19]
Netbooks are mostly sold with light-weight operating systems such as Linux, Windows XP and Windows 7 Starter edition.
Because they are 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 drives 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 subnotebooks, netbooks also generally have a smaller-capacity hard drive, slower CPU, and a lower-profile RAM capacity.[23]
In 2009, Google announced an operating system called Google Chrome OS for this market.
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
Main article: Rugged computer
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,[24] 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
See also: Tablet computer
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.
Tablet laptops have the advantage to offer the keyboard and pointing device (usually a trackpad) of older laptops, for users who do not use the touchscreen display as the primary method of input. Tablets are also touchscreen.
Components
Main article: Personal computer hardware
The following list summarizes the differences and distinguishing features of laptop components in comparison to desktop personal computer parts:[26]
- Central processing unit (CPU): Laptop CPUs have advanced power-saving features and produce less heat than desktop processors, but are not as powerful.[27] There is a wide range of CPUs designed for laptops available from Intel (Pentium M, Celeron M, Intel Core and Core 2 Duo), AMD (Athlon, Turion 64, and Sempron), VIA Technologies, Transmeta and others. On the non-x86 architectures, Motorola and IBM produced the chips for the former PowerPC-based Apple laptops (iBook and PowerBook). Most laptops have removable CPUs, although some support by the motherboard may be restricted to the specific models.[28] Some laptops use a desktop processor instead of the laptop version. Those laptops have high performance at the cost of being likely to have overheating problems, and having less battery life. In other laptops the CPU is soldered on the motherboard and is non-replaceable.
- Memory (RAM): SO-DIMM memory modules that are usually found in laptops are about half the size of desktop DIMMs.[26] 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 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 (formerly PCMCIA) or ExpressCard bay for expansion cards is often present on laptops to allow adding and removing functionality, even when the laptop is powered on. Some subsystems such as: Ethernet, Wi-Fi, or a Wireless modem cellular modem can be implemented as replaceable internal expansion cards, usually accessible under an access cover on the bottom of the laptop. Two popular standards for such cards are MiniPCI and its successor, the PCI Express Mini.[29]
- 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 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 the CMOS 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. 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: 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, 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.[30] 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.[31] 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.[32]
- 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 netbooks 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 you to fit more onscreen at a time, thus improving your ability to multitask. A higher resolution in a fixed size display will make items onscreen appear smaller than they would on a lower resolution. The difference between available display resolutions will often affect the user's experience considerably more than the difference between available processors and available memory, but it is commonly misconceived to be the opposite. 15.6" 1366 × 768 displays and 17.3" 1600 × 900 displays make items onscreen rather large, and tend to have poor image quality due in part to low contrast compared to their higher-resolution counterparts such as 15.6" 1600×900, 15.6" 1920×1080, and 17.3" 1920×1080, because the lower resolution displays are generally more cheaply manufactured. If you as a buyer have a budget that allows you to get a laptop that one of the higher-resolution displays and at the same time suits your needs, and if you don't require the larger text provided by a lower resolution for eyesight-related reasons, then it is commonly recommended that you avoid buying laptops that come with the lower-resolution 15.6" 1366 × 768 displays or 17.3" 1600 × 900 displays. 1366 × 768-resolution displays of sizes 14" and under tend to exhibit the same low-contrast-related poor image quality, but do not make items onscreen as large. 1600 × 900 resolution is occasionally available in sizes of 13.3" and 14", improving multitasking capability, but it is rare for such displays to have noticeably better contrast.
- 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 netbooks. CD drives are becoming rare, while Blu-ray is becoming more common on notebooks.[33]
- 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).
- Input: A pointing stick, touchpad or both are used to control the position of the cursor on the screen, and an integrated keyboard is used for typing. An external keyboard and/or mouse may be connected using USB or PS/2 port, or Bluetooth (if present).
- 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. S-video or composite video 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 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, 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 and MacBook Air also employ the case of the machine as a "gigantic" heat sink, and rely on it to pump heat out of the device core.[citation needed]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 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 FireWire.
Charging stations
Laptop charging trolleys, also known as laptop trolleys or laptop carts, are mobile storage containers to charge laptops, netbooks and tablet computers en masse. The trolleys are predominantly used in schools that have replaced their traditional static ICT[34] suites of desktop computers with laptops, but do not have enough plug sockets in their buildings to charge all of the devices.The trolleys can be wheeled between rooms and classrooms so that anyone in a particular building can access fully charged IT[35] 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, netbooks 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.[34]
Solar panels
Main article: Solar notebook
In certain 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.[37][38] Samsung has also designed a NC215S Solar powered notebook that will be sold commercially in the US market.[39]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, 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.
sumber: http://en.wikipedia.org/wiki/Laptop
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