Laptop
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A laptop computer or simply laptop (also notebook computer or notebook) is a small mobile personal computer, usually weighing from one to three kilograms, depending on size, materials and other factors.
While the terms "laptop" and "notebook" are often used interchangeably, "laptop" is the older term, introduced in 1983 with the Gavilan SC. "Notebook computer" is a later coinage, which was used to differentiate smaller devices such as those of the Compaq LTE series in 1989, which were, in contrast to previous laptops, the approximate size of an A4 paper sheet.As far as this distinction is concerned, the "thickness" ("vertical height") of the machine is disregarded; only its width and depth are considered Either term is often used improperly: due to heat and other issues, many laptops are inappropriate for use on one's lap, and most are not the size of an A4 sheet. Moreover, some older portable computers, such as the Macintosh Portable and certain Zenith TurbosPort models, were sometimes described as "laptops", although their size and weight were too great for this category.
Laptops usually run on a single battery or from an external AC/DC adapter which can charge the battery while also supplying the computer itself.
As personal computers, laptops are capable of the same tasks as a desktop PC, although they are typically less powerful for the same price. They contain components that are similar to their desktop counterparts and perform the same functions, but are miniaturized and optimized for mobile use and efficient power consumption. Laptops usually have liquid crystal displays and use different memory modules for their RAM (for instance, SO-DIMM in lieu of the larger DIMMs). In addition to a built-in keyboard, they may utilize a touchpad (also known as a trackpad) or a pointing stick for input, though an external keyboard or mouse can usually be attached.
Categories
Terms sometimes used for subtypes of laptop computers include:-->
- Ultraportables
- Laptops with screens typically less than 12 inches diagonally and a weight of less than 1.7kg. Their primary audience is usually business travellers, who need small, light laptops. Ultraportables are often very expensive and house power-saving CPUs and almost always have integrated graphics.
- Thin-and-lights
- Laptops usually weighing in between 1.8kg and 2.8kg with a screen size of between 12 and 14 inches diagonally.
- Medium-sized laptops
- These usually have screens of 15 - 15.4 inches diagonally and a weight of around 3-3.5kg.
- Desktop replacement computers
- Powerful laptops meant to be mainly used in a fixed location and infrequently carried out due to their weight and size; the latter provides more space for powerful components and a big screen - usually measuring 15 inches or more. Desktop replacements often have limited battery life due to their hardware, rarely exceeding three hours.
History
Before laptop/notebook computers were technically feasible, similar ideas had been proposed, most notably Alan Kay's Dynabook concept, developed at Xerox PARC in the early 1970s.The first commercially available portable computer was the Osborne 1 in 1981, which used the CP/M operating system. Although it was large and heavy compared to today's laptops, with a tiny CRT monitor, it had a near-revolutionary impact on business, as professionals were able to take their computer and data with them for the first time. This and other "luggables" were inspired by what was probably the first portable computer, the Xerox NoteTaker, again developed at Xerox PARC, in 1976; however, only ten prototypes were built. The Osborne was about the size of a portable sewing machine, and importantly could be carried on a commercial aircraft. However, it was not possible to run the Osborne on batteries; it had to be plugged in.
A more enduring success was the Compaq Portable, the first product from Compaq, introduced in 1983, by which time the IBM Personal Computer had become the standard platform. Although scarcely more portable than the Osborne machines, and also requiring AC power to run, it ran MS-DOS and was the first true IBM clone (IBM's own later Portable Computer, which arrived in 1984, was notably less IBM PC-compatible than the Compaq).
Another significant machine announced in 1981, although first sold widely in 1983, was the Epson HX-20. A simple handheld computer, it featured a full-transit 68-key keyboard, rechargable nickel-cadmium batteries, a small (120 x 32-pixel) dot-matrix LCD display with 4 lines of text, 20 characters per line text mode, a 24 column dot matrix printer, a Microsoft BASIC interpreter, and 16 kB of RAM (expandable to 32 kB).
However, arguably the first true laptop was the GRiD Compass 1101, designed by Bill Moggridge in 1979-1980, and released in 1982. Enclosed in a magnesium case, it introduced the now familiar clamshell design, in which the flat display folded shut against the keyboard. The computer could be run from batteries, and was equipped with a 320×200-pixel plasma display and 384 kilobyte bubble memory. It was not IBM-compatible, and its high price (US$ 10,000) limited it to specialized applications. However, it was used heavily by the U.S. military, and by NASA on the Space Shuttle during the 1980s. The GRiD's manufacturer subsequently earned significant returns on its patent rights as its innovations became commonplace. GRiD Systems Corp. was later bought by Tandy (RadioShack).
Two other noteworthy early laptops were the Sharp PC-5000 and the Gavilan SC, announced in 1983 but first sold in 1984. The Gavilan was notably the first computer to be marketed as a "laptop". It was also equipped with a pioneering touchpad-like pointing device, installed on a panel above the keyboard. Like the GRiD Compass, the Gavilan and the Sharp were housed in clamshell cases, but they were partly IBM-compatible, although primarily running their own system software. Both had LCD displays, and could connect to optional external printers.
The year 1983 also saw the launch of what was probably the biggest-selling early laptop, the Kyocera Kyotronic 85, which owed much to the design of the previous Epson HX-20. Although it was at first a slow seller in Japan, it was quickly licensed by Tandy Corporation, Olivetti, and NEC, which saw its potential and marketed it respectively as TRS-80 Model 100 line (or Tandy 100), Olivetti M-10, NEC PC-8201.See [TRS-80 Model 100 / 102] at old-computers.com The machines ran on standard AA batteries. The Tandy's built-in programs, including a BASIC interpreter, a text editor, and a terminal program, were supplied by Microsoft, and are thought to have been written in part by Bill Gates himself. The computer was not a clamshell, but provided a tiltable 8×40-character LCD screen above a full-travel keyboard. With its internal modem, it was a highly portable communications terminal. Due to its portability, good battery life (and ease of replacement), reliability (it had no moving parts), and low price (as little as US$ 300), the model was highly regarded, becoming a favorite among journalists. It weighed less than 2 kg with dimensions of 30 × 21.5 × 4.5 cm (12 × 8.5 × 1.75 inches). Initial specifications included 8 kilobyte of RAM (expandable to 24 kB) and a 3 MHz processor. The machine was in fact about the size of a paper notebook, but the term had yet to come into use and it was generally described as a "portable" computer.
Among the first commercial IBM-compatible laptops were the IBM PC Convertible, introduced in 1986, and two Toshiba models, the T1000 and T1200, introduced in 1987. Although limited floppy-based DOS machines, with the operating system stored in read-only memory, the Toshiba models were small and light enough to be carried in a backpack, and could be run off lead-acid batteries. These also introduced the now-standard "resume" feature to DOS-based machines: the computer could be paused between sessions, without having to be restarted each time.
Another notable computer was the Cambridge Z88, designed by Clive Sinclair, introduced in 1988. About the size of an A4 sheet of paper as well, it ran on standard batteries, and contained basic spreadsheet, word processing, and communications programs. It anticipated the future miniaturization of the portable computer; and, as a ROM-based machine with a small display, can — like the TRS-80 Model 100 — also be seen as a forerunner of the personal digital assistant.
By the end of the 1980s, laptop computers were becoming popular among business people. The NEC Ultralite, released in mid-1989, was perhaps the first notebook computer, weighing just over 2 kg; in lieu of a floppy or hard drive, it contained a 2 megabyte RAM drive, but this reduced its utility as well as its size. The first notebook computers to include hard drives were those of the Compaq LTE series, introduced toward the end of that year. Truly the size of a notebook, they also featured backlit displays with CGA resolutions (though not CGA colors).
The first Apple Computer machine designed to be used on the go was the 1989 Macintosh Portable (although an LCD screen had been an option for the transportable Apple IIc in 1984). Actually a "luggable", the Mac Portable was praised for its clear active matrix display and long battery life, but was a poor seller due to its bulk. In the absence of a true Apple laptop, several compatible machines such as the Outbound Laptop were available for Mac users; however, for copyright reasons, the user had to supply a set of Mac ROMs, which usually meant having to buy a new or used Macintosh as well.
The Apple PowerBook series, introduced in October 1991, pioneered changes that are now de facto standards on laptops, such as the placement of the keyboard, room for palm rest, and the inclusion of a built-in pointing device (a trackball). The following year, IBM released its Thinkpad 700C, featuring a similar design (though with a distinctive red TrackPoint pointing device).
Later PowerBooks introduced the first 256-color displays (PowerBook 165c, 1993), and first true touchpad, first 16-bit sound recording, and first built-in Ethernet network adapter (PowerBook 500, 1994).
As technology improved during the 1990s, the usefulness and popularity of laptops increased. Correspondingly prices went down. Several developments specific to laptops were quickly implemented, improving usability and performance. Among them were:
- Improved battery technology. The heavy lead-acid batteries were replaced with lighter and more efficient technologies, first nickel metal hydride (NiMH) and then lithium ion battery and lithium polymer.
- Power-saving processors. While laptops in 1991 were limited to the 80286 processor because of the energy demands of the more powerful 80386, the introduction of the Intel 386SX processor, designed for the specific power needs of laptops, marked the point at which laptop needs were included in CPU design.
- Improved liquid crystal displays, in particular active-matrix LCD technology. Early laptop screens were black and white or grayscale passive-matrix LCDs prone to heavy shadows and blurry movement (some portable computer screens were sharper monochrome plasma displays, but these drew too much current to be powered by batteries). Improvements in production technology meant displays became larger, sharper, had higher native resolutions, and could display color with great accuracy, making them an acceptable substitute for a traditional CRT monitor.
- Improved hard disk technology. Early laptops and portables had only floppy disk drives. As thin, high-capacity hard disk drives with higher reliability and shock resistance and lower power consumption became available, users could store their work on laptop computers and take it with them.
- Improved connectivity. Internal modems and standard serial, parallel, and PS/2 ports on IBM PC-compatible laptops made it easier to work away from home; the addition of network adapters and, from 1997, USB, as well as, from 1999, Wi-Fi, made laptops as easy to use with peripherals as a desktop computer.
The $100 laptop
In 2005, faculty members from the MIT Media Lab including Nicholas Negroponte introduced the $100 laptop and the One Laptop Per Child project. The aim is to design, manufacture, and distribute laptops that are sufficiently inexpensive to provide every child in the world access to knowledge and modern forms of education. The laptops are to be sold to governments and issued to children by schools. These equipments, of which many prototypes have already been presented, will be rugged, Linux-based, and so energy efficient that a hand-cranking dynamo can alone provide sufficient power for operation. Ad-hoc wireless mesh networking may be used to allow many machines to share a single Internet connection.
Parts
- Most modern laptops feature 12 inch (304.8 mm) or larger active matrix displays with resolutions of 1024×768-pixels and above, and have a PC-Card expansion bay for expansion cards (formerly PCMCIA). Internal hard disks are physically smaller –2.5 inch (63.5 mm)– compared to the standard desktop 3.5 inch (88.9 mm) drive, and usually have lower performance and power consumption. Video and sound chips are usually integrated. This tends to limit the use of laptops for gaming and entertainment, two fields which have constantly escalating hardware demands. However, higher end laptops can come with dedicated graphics processors, such as the Dell Inspiron E1505 and E1705, which can be bought with an ATI Mobility Radeon X1300 or similar. These mobile graphics processors tend to have less performance than their desktop counterparts, but this is because they have been optimized for lower power usage.
- There is a wide range of laptop specific processors available from Intel (Pentium M –with Centrino technology–, Celeron, Intel Core Duo and Centrino Duo) and from AMD (Athlon, Turion 64, and Sempron). Motorola and IBM developed and manufactured the Chips for the Former PowerPC based Apple laptops(iBook and PowerBook). Generally, laptop processors are less powerful than their desktop counterparts, due to the need to save energy and reduce heat dissipation. However, the PowerPC G3 and G4 processor generations have been able to offer almost the same performance as their desktop versions, limited mostly by other factors, such as the system bus bandwidth; recently, though, with the introduction of the G5s, they have been far outstripped. At one point, the Pismo G3, at up to 500 MHz, was faster than the fastest desktop G3 (then the B&W G3), which ran at 450 MHz.
- Current models use lithium ion and more recently lithium polymer batteries, which have largely replaced the older nickel metal-hydride technology. Typical battery life for most laptops is two to five hours with light-duty use, but may drop to as little as one hour with intensive use. Batteries gradually deteriorate over time and eventually need to be replaced in one to five years, depending on the charging and discharging pattern.
- Docking stations may be used for expanding connectors and quickly connecting many components to the laptop, although they are falling out of favour as laptops on board USB and firewire ports have become de facto standards.
- Virtually all laptops can be powered from an external AC converter. This device typically adds half a kilogram (1 lb) to the overall "transport weight" of the equipment.
Upgradability
Laptops' upgradability is severely limited, both for technical and economic reasons. As of 2006, there is no industrywide standard form factor for laptops. Each major laptop vendor pursues its own proprietary design and construction, with the result that laptops are difficult to upgrade and exhibit 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. Standard feature peripherals (such as audio, video, USB, 1394, WiFi, Bluetooth) are generally integrated on the main PCB, and are thus not user-upgradable. Other components, such as RAM modules, hard drives, and batteries are typically user-upgradable.Many laptops have removable CPUs, although support for other CPUs is restricted to the specific models supported by the laptop motherboard. The socketed CPUs are perhaps for the manufacturer's convenience, rather then end-user upgrades. In many other laptops, the CPU is soldered and non-replaceable. Thus there is no practical way to update it on models which already feature the latest processor for their motherboard.
Many laptops also include an internal MiniPCI slot, but as with the CPU, the internal slot is restricted in the range of cards that can be installed. The widespread adoption of USB mitigates I/O connectivity to a great degree, although the user must carry the USB peripheral as a separate item.
NVidia and ATI have proposed a standardized interface for laptop GPU upgrades (such as an MXM), but again, choices are limited compared to the desktop PCIe/AGP aftermarket.
Performance
For a given price range (and manufacturing base), laptop computational power has traditionally trailed that of desktops. By virtue of their usage goals, laptops prioritize energy-efficiency and bulk over absolute performance. Desktop computers and their modular components are built to fit much larger standard enclosures, along with the expectation of (AC) wall-power. As such, energy-efficiency and portability for desktops are secondary design goals compared to absolute performance.
For typical home (personal-use) applications, where the computer spends the majority of its time sitting idle for the next user-input, laptops of the thin-client type or larger, are generally fast enough to achieve transparency. 3D-gaming, multimedia (video) encoding and playback, and analysis-packages (database, math, engineering, financial, etc.) are areas where desktops still offer the casual user a compelling advantage.