history of personal computer

A personal computer (PC) is a microcomputer whose price, size, and capabilities make it useful for individuals.

We may never know who coined the phrase with the intent of a small affordable computing device but John W. Mauchly described such a device in a November 3, 1962 New York Times article entitled "Pocket Computer may replace Shopping List". Six years later a manufacturer took a risk at referring to their product this way when Hewlett Packard advertised their "Powerful Computing Genie" as "The New Hewlett Packard 9100A personal computer"[1]. This advertisement was too extreme for the target audience and replaced with a much drier ad for the HP 9100A programmable calculator. [2] [3] [4] During the next 7 years the phrase had gained usage so when Byte magazine, published its first edition it referred to its readers as being in the "personal computing field"[5] while Creative Computing defined the personal computer as a "non-(time)shared system containing sufficient processing power and storage capabilities to satisfy the needs of an individual user." [6] Two years later when the 1977 Trinity of preassembled small computers hit the markets, the Apple II[7] and the PET 2001[8] were advertised as 'personal computers' while the TRS-80 was a microcomputer used for household tasks including "personal financial management". By 1979 over half a million home computers were sold and the youth of the day had a new concept of the personal computer. [9]

Personal computers are also known as microcomputers and home computers. Often, the term "personal computer" is used exclusively for computers running a Microsoft Windows operating system, but this is erroneous. For example, a Macintosh running Mac OS and an IBM PC compatible running Linux are both personal computers. This confusion stems from the fact that the term "PC" is often used as a shorthand form for "IBM PC compatible" and historically Mac OS has run on non-IBM compatible hardware like the PowerPC architecture. Linux runs on virtually any kind of hardware, but was developed later and has not achieved popularity comparable to Microsoft Windows.

Contents [hide]
1 History
1.1 Mainframes and large minicomputers
1.2 Computers at home
1.3 Back to business
1.4 Today
2 Uses
3 Configuration
3.1 Computer components
3.2 Motherboard
3.3 Central processing unit
3.4 Main memory
3.5 Mass storage
3.6 Video card
4 Laptop computers
5 List of other non-IBM-PC-compatible business PCs
5.1 Pre-IBM-PC personal business computer systems
5.2 Post-IBM-PC personal business computer systems
6 See also
7 Notes
8 Further reading
9 External links



[edit] History
Main article: History of computing hardware (1960s-present)

[edit] Mainframes and large minicomputers

Time shared computer terminals connected to central computers, such as the TeleVideo ASCII character mode smart terminal pictured here, were sometimes used before the advent of the PC.Before the introduction of the microprocessor in the early 1970s, computers were generally large, costly systems owned by large corporations, universities, government agencies, and similar-sized institutions. End users often did not directly interact with the machine but instead would prepare tasks for the computer on off-line equipment, such as card punches. A number of assignments for the computer would be gathered up and processed in batch mode. After the job had completed, users could collect the results. In some cases it could take hours or days between submitting a job to the computing center and receiving the output.

A more interactive form of computer use developed commercially by the middle 1960s. In a time-sharing system, multiple computer terminals let many people share the use of one mainframe computer processor. This was common in business applications and in science and engineering.

A different model of computer use was foreshadowed by the way in which early, pre-commercial, experimental computers were used, where one user had exclusive use of a processor. Some of the first computers that might be called "personal" were early minicomputers such as the LINC and PDP-8, and later on VAX and larger minicomputers from Digital Equipment Corporation (DEC), Data General, Prime Computer, and others. By today's standards they were very large (about the size of a refrigerator) and cost prohibitive (typically tens of thousands of US dollars), and thus were rarely purchased by an individual. However, they were much smaller, less expensive, and generally simpler to operate than many of the mainframe computers of the time. Therefore, they were accessible for individual laboratories and research projects. Minicomputers largely freed these organizations from the batch processing and bureaucracy of a commercial or university computing center.

In addition, minicomputers were relatively interactive and soon had their own operating systems. The minicomputer Xerox Alto (1973) was a landmark step in the development of personal computers, because of its graphical user interface, bit-mapped high resolution screen, large internal and external memory storage, mouse, and special software. [10] The minicomputer era was an intermediary step from mainframes to personal computer usage.

Minicomputers were available to smaller organizations than those that once used mainframes, but were not aimed at individuals, Ken Olsen, founder of DEC, has been widely quoted as saying in 1971 "I can think of no reason why an individual would want to own a computer."[verification needed] This was understandable, considering what DEC was offering: only a fairly large organization could use or afford a machine the size of an average home refrigerator that required external terminals to operate and program. A few individuals, such as Steve Wozniak, had differing views, as will be seen below.


[edit] Computers at home

The 1977 Apple II, one of the 1977 Trinity. Floppy drive pictured was 3rd party addition.One early use of the term "personal computer" appeared in a November 3, 1962, New York Times article reporting John W. Mauchly's vision of future computing as detailed at a recent meeting of the American Institute of Industrial Engineers. Mauchly stated, "There is no reason to suppose the average boy or girl cannot be master of a personal computer.[11]"

The minicomputer ancestors of the modern personal computer used early integrated circuit (microchip) technology, which reduced size and cost, but they contained no microprocessor. This meant that they were still large and difficult to manufacture just like their mainframe predecessors. After the "computer-on-a-chip" was commercialized, the cost to manufacture a computer system dropped dramatically. The arithmetic, logic, and control functions that previously occupied several costly circuit boards were now available in one integrated circuit, making it possible to produce them in high volume. Concurrently, advances in the development of solid state memory eliminated the bulky, costly, and power-hungry magnetic core memory used in prior generations of computers.

There were a few researchers at places such as SRI and Xerox PARC who were working on computers that a single person could use and could be connected by fast, versatile networks: not home computers, but personal ones.

A programmable terminal called the Datapoint 2200 is the earliest known device that bears any significant resemblance to the modern personal computer[12][13]. It was made by CTC (now known as Datapoint) in 1970 and was a complete system in a small case bearing the approximate footprint of an IBM Selectric typewriter. The system's CPU was constructed from a variety of discrete components, although the company had commissioned Intel to develop a single-chip processing unit; there was a falling out between CTC and Intel, and the chip Intel had developed wasn't used. Intel soon released a modified version of that chip as the Intel 8008, the world's first 8-bit microprocessor[14]. The needs and requirements of the Datapoint 2200 therefore determined the nature of the 8008, upon which all successive processors used in IBM-compatible PCs were based. Additionally, the design of the Datapoint 2200's multi-chip CPU and the final design of the Intel 8008 were so similar that the two are largely software-compatible; therefore, the Datapoint 2200, from a practical perspective, can be regarded as if it were indeed powered by an 8008, which makes it a strong candidate for the title of "first microcomputer" as well.

Development of the single-chip microprocessor was an enormous catalyst to the popularization of cheap, easy to use, and truly personal computers. The Altair 8800, introduced in a Popular Electronics magazine article in the January 1975 issue, at the time set a new low price point for a computer, bringing computer ownership to an admittedly select market in the 1970s. This was followed by the IMSAI 8800 computer, with similar abilities and limitations. The Altair and IMSAI were essentially scaled-down minicomputers and were incomplete: to connect a keyboard or screen to them required heavy, expensive "peripherals". These machines both featured a front panel with switches and lights, which communicated with the operator in binary. To program the Machine, one didn't simply power up: one first had to key in the bootstrap loader program in binary, then read in a paper tape containing a BASIC interpreter, using a massive paper-tape reader. Keying the loader required setting a bank of eight switches up or down and pressing the "load" button, once for each byte of the program, which was typically hundreds of bytes long. This was before one could begin to do any computing.

In 1976, the Kooro Manufacturing & Electronics Cooperative in Skopje, Macedonia produced in limited quantities, an all in one (integrated keyboard, monochrome monitor, 8 inch floppy disk drive and 16k of ram) for use by government officials. Similar in appearance to the TRS-80 Model III computer using a proprietary operating system.[verification needed]

It was arguably the Altair computer that spawned the development of Apple, as well as Microsoft which produced and sold the Altair BASIC programming language interpreter, Microsoft's first product. The second generation of microcomputers — those that appeared in the late 1970s, sparked by the unexpected demand for the kit computers and the Steve Wozniak-designed Apple release, the Apple I — were usually known as home computers. For business use these systems were less capable and in some ways less versatile than the large business computers of the day. They were designed for fun and educational purposes, not so much for practical use. And although you could use some simple office/productivity applications on them, they were generally used by computer enthusiasts for learning to program and for running computer games, for which the personal computers of the period were less suitable and much too expensive. For the more technical hobbyists home computers were also used for electronics interfacing, such as controlling model railroads, and other general hobbyist pursuits.

The MOS 6500 series microprocessor lead to a reduction in the expense of creating computing systems. The Commodore PET, the TRS 80, and the Apple II, also known as the 1977 Trinity by Byte magazine, are often cited as the first personal computers. Specifically, the Commodore PET, which Byte called the first [15]. The design of the Commodore PET, a single integrated machine with a built in monitor, keyboard, and datasette device, and the operating system of the Xerox Alto went on to inspire the popular Macintosh computer, by Apple.

A 1978 ad for the Apple II used the wording "Apple, the personal computer". There was no trademark symbol. Three years later, the term "personal computer" was a trademark of IBM, which had decided to invade Apple's turf and had done it successfully; a few years later, a judge declared that "personal computer" was no longer an IBM trademark, but a generic term for any personal computer not made by Apple.[citation needed]


[edit] Back to business

A release photo of the original IBM PC (ca. 1981).It was the launch of the VisiCalc spreadsheet, initially for the Apple II (and later for the Atari 8-bit family, Commodore PET, and IBM PC) that turned the microcomputer into a business tool. In fact, An Apple employee discovered in 1980 that IBM's San Jose research lab had purchased several Apple IIs, solely to run VisiCalc.

This was followed by the August 12, 1981 release of the IBM PC, which would revolutionize the computer market. The Lotus 1-2-3, a combined spreadsheet (inspired by VisiCalc), presentation graphics, and simple database application, would become the PC's own killer application. Good word processor programs would also appear for many home computers, in particular the introduction of Microsoft Word for the Apple Macintosh in 1985 (while earlier versions of Word had been created for the PC, it became popular initially through the Macintosh).

In the January 3, 1983 issue of Time magazine, the personal computer was named the "Person of the Year" for 1982.


[edit] Today

A university computer lab containing many desktop PCsDuring the 1990s, the power of personal computers increased radically, blurring the formerly sharp distinction between personal computers and multi-user computers, such as mainframes. Today higher-end computers often distinguish themselves from personal computers by greater reliability or greater ability to multitask, rather than by brute CPU ability alone.

In today's common usage, personal computer and PC usually indicate an IBM PC compatible. Due to this association, some manufacturers of personal computers that are not IBM PCs avoid explicitly using the terms to describe their products.

Due to networks, the Internet and such factors as digital rights management, modern personal computers are no longer the exclusive tools of their users. Support of desktop computers in business now requires as much bureaucracy and professional training as did operating a time-sharing system, with the drawback of much lower security and many users skilled enough to get into trouble but not skilled enough to get out.

Modern computers are thousands of times more powerful than those of only twenty years ago. Multi-core processors, a gigabyte of RAM and hard drives of several hundred gigabytes have become the norm. These numbers eclipse even supercomputers from past decades.


[edit] Uses
Personal computers are normally operated by one user at a time to perform such general purpose tasks as word processing, Internet browsing, Internet faxing, e-mail and other digital messaging, multimedia playback, computer game play, computer programming, etc. The user of a modern personal computer may have significant knowledge of the operating environment and application programs, but is not necessarily interested in programming nor even able to write programs for the computer. Therefore, most software written primarily for personal computers tends to be designed with simplicity of use, or "user-friendliness" in mind. However, the software industry continuously provide a wide range of new products for use in personal computers, targeted at both the expert and the non-expert user.


[edit] Configuration

An exploded view of a modern personal computer:
Monitor
Motherboard
CPU (Microprocessor)
Primary storage (RAM)
Expansion cards
Power supply
Optical disc drive
Secondary storage (Hard disk)
Keyboard
Mouse
Personal computers can be categorized by size and portability:

Desktop computers
Laptop or notebooks
Personal digital assistants (PDAs)
Portable computers
Tablet computers
Wearable computers
This section describes the desktop computer because it's the most complete and one can easily look inside the case. The others have the same basic setup, but usually lack the peripherals.


[edit] Computer components
Main article: Computer hardware
A minimal setup of a typical contemporary desktop computer would be:

Computer case with power supply (usually sold together)
Motherboard
Processor with fan (usually sold together)
At least one memory card
Mass storage
Keyboard and mouse for input
Monitor for output
The motherboard connects everything together. The memory card(s), graphics card and processor are mounted directly onto the motherboard (the processor in a socket and the memory and graphics cards in an expansion slot). The mass storage is connected to it with cables. Same for keyboard and mouse, except that they are external and connect to the back plate. The monitor is also connected to the back plate, except not (usually) directly to the motherboard, but to a connector in the graphics card.

The mass storage can be:
Hard disk
Floppy drive or zip drive (both with media)
Optical drive (CD or DVD)
The operating system (e.g.: Microsoft Windows, Linux or many others) can be located on either of these, but typically it's on one of the hard disks. A live cd is also possible, but very slow and used for either installation of the OS or problem solving.
On top of these, a typical computer also has:

Sound card
Network card
Modem and possibly router
Common additions, connected on the outside (peripherals), are:

Printer
Scanner
Webcam
Speakers
Microphone
Headset
Card reader
Gaming devices such as a joystick
Several functions (implemented by chipsets) can be integrated into the motherboard, such as typically USB and network, but also graphics and sound. But even if these are present, a separate card can be added if what is available isn't sufficient.

The graphics and sound card can have a break out box to keep the analog parts away from the electromagnetic radiation inside the computer case. For really large amounts of data, a tape drive can be used or (extra) hard disks can be put together in an external case.

These components can usually be put together with little knowledge, to build a computer. If something shouldn't go somewhere, it usually doesn't fit (this used to not always be the case in the past) and if it does fit it can usually do little harm.

Most personal computers are standardized to the point that purchased software is expected to run with little or no customization for the particular computer. Many PCs are also user-upgradeable, especially desktop and workstation class computers. Devices such as main memory, mass storage, even the motherboard and central processing unit may be easily replaced by an end user. This upgradeability is, however, not indefinite due to rapid changes in the personal computer industry. A PC that was considered top-of-the-line five or six years prior may be impractical to upgrade due to changes in industry standards. Such a computer usually must be totally replaced once it's no longer suitable for its purpose. This upgrade and replacement cycle is partially related to new releases of the primary mass-market operating system, which tends to drive the acquisition of new hardware and tends to obsolete previously serviceable hardware (see planned obsolescence).

The hardware capabilities of personal computers can sometimes be extended by the addition of expansion cards connected via an expansion bus. Some standard peripheral buses often used for adding expansion cards in personal computers as of 2005 are PCI, AGP (a high-speed PCI bus dedicated to graphics adapters), and PCI Express. Most personal computers as of 2005 have multiple physical PCI expansion slots. Many also include an AGP bus and expansion slot or a PCI Express bus and one or more expansion slots, but few PCs contain both buses.


[edit] Motherboard
Main article: Motherboard
The motherboard (or mainboard) is the primary circuit board within a personal computer. Many other components connect directly or indirectly to the motherboard. Motherboards usually contain one or more CPUs, supporting circuitry -- usually integrated circuits (ICs) providing the interface between the CPU memory and input/output peripheral circuits, main memory, and facilities for initial setup of the computer immediately after being powered on (often called boot firmware or, in IBM PC compatible computers, a BIOS). In many portable and embedded personal computers, the motherboard houses nearly all of the PC's core components. Often a motherboard will also contain one or more peripheral buses and physical connectors for expansion purposes. Sometimes a secondary daughter board is connected with the motherboard to provide further expandability or to satisfy space constraints.


[edit] Central processing unit
Main article: Central processing unit
The central processing unit, or CPU, is that part of a computer which executes software program instructions. In older computers this circuitry was formerly on several printed circuit boards, but in PC class machines, has been from the first personal computers, a single integrated circuit. Nearly all PCs contain a type of CPU known as a microprocessor. The microprocessor often plugs into the motherboard using one of many different types of socket. IBM PC compatible computers use an x86-compatible processor, usually made by Intel, AMD, VIA Technologies or Transmeta. Apple Macintosh computers were initially built with the Motorola 680x0 family of processors, then switched to the Power PC series (a RISC architecture jointly developed by IBM, Motorola, and Apple Computer), but as of 2006, Apple has switched again, this time to x86 compatible processors.


[edit] Main memory
Main article: Primary storage

A four-megabyte RAM card measuring about twenty-two by fifteen inches (56 by 38 centimeters); made for the VAX 8600 minicomputer (ca. 1986). Dual in-line package (DIP) Integrated circuits populate nearly the whole board; the RAM chips are the most common kind, and located in the rectangular areas to the left and right.A PC's main memory (i.e., its 'primary store') is fast storage that is directly accessible by the CPU, and is used to store the currently executing program and immediately needed data. PCs use semiconductor random access memory (RAM) of various kinds such as DRAM or SRAM as their primary storage. Which exact kind depends on cost/performance issues at any particular time. Main memory is much faster than mass storage devices like hard disks or optical discs, but is usually volatile, meaning it does not retain its contents (instructions or data) in the absence of power, and is much more expensive for a given capacity than is most mass storage. Main memory is generally not suitable for long-term or archival data storage.


[edit] Mass storage
Main article: Hard disk

Internals of a Winchester hard drive with the disks removed.Mass storage devices store programs and data even when the power is off; they do require power to perform read/write functions during usage. Although semiconductor flash memory has dropped in cost, the prevailing form of mass storage in personal computers is still the electromechanical hard disk.

The disk drives use a sealed head/disk assembly (HDA) which was first introduced by IBM's "Winchester" disk system. The use of a sealed assembly allowed the use of positive air pressure to drive out particles from the surface of the disk, which improves reliability.

If the mass storage controller provides for expandability, a PC may also be upgraded by the addition of extra hard disk or optical drives. For example, DVD-ROMs, CD-ROMs, and various optical disc recorders may all be added by the user to certain PCs. Standard internal storage device interfaces are ATA, Serial ATA, SCSI, and CF+ Type II in 2005.


[edit] Video card
Main article: Video card
The video card - otherwise called a graphics card, graphics adapter or video adapter - processes and renders the graphics output from the computer to the computer display, also called the visual display unit (VDU), and is an essential part of the modern computer. On older models, and today on budget models, graphics circuitry tended to be integrated with the motherboard but, for modern flexible machines, they are supplied in PCI, AGP, or PCI Express format.

When the IBM PC was introduced, many existing personal computers used text-only display adapters and had no graphics capability.


[edit] Laptop computers
Main article: Laptop
A laptop computer or simply laptop, also called a notebook computer or notebook, is a small personal computer designed for mobility. Usually all of the interface hardware needed to operate the laptop, such as parallel and serial ports, graphics card, sound channel, etc., are built in to a single unit. Most laptops contain batteries to facilitate operation without a readily available electrical outlet. In the interest of saving power, weight and space, they usually share RAM with the video channel, slowing their performance compared to an equivalent desktop machine.

One main drawback of the laptop is that, due to the size and configuration of components, relatively little can be done to upgrade the overall computer from its original design. Some devices can be attached externally through ports (including via USB); however internal upgrades are not recommended or in some cases impossible, making the desktop PC more modular

A laptop computer, or simply laptop (also notebook computer or notebook), is a small mobile computer, which usually weighs 2.2-18 pounds (1-6 kilograms), depending on size, materials, and other factors.

Laptops usually run on a single main battery or from an external AC/DC adapter which can charge the battery while also supplying power to the computer itself. Many computers also have a 3volt cell to run the clock and other processes in the event of a power failure.

As personal computers, laptops are capable of the same tasks as a desktop computer, 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 most of them use different memory modules for their random access memory (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.

Contents [hide]
1 Categories
1.1 Related devices
2 History
3 Parts
4 Disadvantages
4.1 Standardization issues
4.2 Compatibility issues
4.2.1 Free software
5 Naming conventions
6 Upgradeability
7 Performance
8 Health issues
9 Security
10 Major brands and manufacturers
11 See also
12 References



[edit] Categories
Terms sometimes used for subtypes of laptop computers include:

UMPCs
These Ultra-Mobile PCs are mobile computers with a size comparable to PDAs - they are extremely portable. Because of their small size, they incorporate a 20 cm (7 inch) or smaller touch-screen for the user to interact with it (as with a virtual keyboard), though some (such as the OQO Model 02) are designed with a miniature physical keyboard (a thumbboard) and mouse interface. They house lower performing, power-saving components (in comparison to larger laptops). Examples of UMPCs are the OQO Model 02 and the Sony Vaio UX Micro PC.
Ultraportables
Laptops with screens typically less than 11 inches diagonally and a weight of less than 1.7kg. Their keyboards are usually not full-size. Their primary audience is usually business travelers, who need small, light laptops. Ultraportables are often very expensive, have extended battery life, house power-saving CPUs and almost always have integrated graphics.

A Sony VAIO FJ76 NotebookThin-and-lights
Laptops usually weighing in between 1.8kg and 2.8kg with a screen size of between 12 and 14 inches diagonally. Examples of this variety: the Sony VAIO FJ, Apple Inc. MacBook and Dell XPS M1210 and XPS M1330.
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 15-20 inches. Desktop replacements tend to have limited battery life, rarely exceeding three hours, because the hardware is not optimized for efficient power usage. Sometimes called a luggable laptop.

[edit] Related devices
Laptops can be understood as a particular point on the continuum of more or less portable computing devices: the point at which the device is large enough to use substantially the same software as a desktop machine, but small enough to support Mobile computing. Other points on the continuum include:

Transportables, also called portable computers
Computers which can easily be moved from place to place, but cannot be used while in transit, usually because they require AC power. The most famous example is the Osborne 1. A transportable, like a laptop, can run desktop software; but it does not support mobile computing.
Tablets
Computers shaped like slates or (paper) notebooks, with touchscreen interfaces. As of 2007, the most common subcategory is the Tablet PC, which is essentially a laptop with a touchscreen. Some tablets have no keyboard; others, called "convertibles", have a keyboard which can be folded behind the screen. A tablet supports mobile computing, and, commonly, can run some desktop software (possibly with modification), but not all.
Ultra Mobile PCs (UMPCs)
Very small Tablet PCs.
Internet tablets
Internet appliances in tablet form. An internet tablet supports mobile computing, but usually does not run any desktop software.
Personal digital assistants (PDAs)
Small computers, usually pocket-sized, usually with limited functionality. A PDA supports mobile computing, but almost never runs any desktop software.
Handheld computers
A high-end PDA or small tablet.
Smartphone
A handheld or PDA with an integrated cellphone.
As will be clear, these categories are blurry at times. For example, the OQO UPC is a PDA-sized Tablet PC; the Apple eMate had the clamshell form factor of a laptop, but ran PDA software. The HP Omnibook line of laptops included some devices small enough to be called handheld computers. The hardware of the Nokia 770 Internet tablet is essentially the same as that of a PDA such as the Zaurus 6000; the only reason it's not called a PDA is that it doesn't have PIM software. On the other hand, both the 770 and the Zaurus can run some desktop Linux software, usually with modifications.


[edit] 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 into mains.

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[citation needed]).

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, rechargeable 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 KiB of RAM (expandable to 32 KiB).

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 kibibyte bubble memory. It was not IBM-compatible, and its high price (US$ 8-10,000) 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.[1] 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 kibibytes of RAM (expandable to 24 KiB) 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 early laptop was the Dulmont Magnum, made in Australia and launched internationally in 1984.[2]

The first laptops successful on a large scale came in large part due to a Request For Proposal (RFP) by the U.S. Air Force in 1987. This contract would eventually lead to the purchase of over 200,000 laptops. Competition to supply this contract was fiercely contested and the major PC companies of the time; IBM, Toshiba, Compaq, NEC, and Zenith Data Systems (ZDS), rushed to develop laptops in an attempt to win this deal. ZDS, which had earlier won a landmark deal with the IRS for its Z-171, was awarded this contract for its SupersPort series. The SupersPort series was originally launched with an Intel 8086 processor, dual floppy disk drives, a backlit, blue and white STN LCD screen, and a NiCD battery pack. Later models featured an Intel 80286 processor and a 20 MB hard disk drive. On the strength of this deal, ZDS became the world's largest laptop supplier in 1987 and 1988.

ZDS partnered with Tottori Sanyo in the design and manufacturing of these laptops. This relationship is notable because it was the first deal between a major brand and an Asian OEM (Original Equipment Manufacturer). At the time, Compaq, IBM, Toshiba, NEC, etc. all designed and manufactured their own machines. However, after the success of the ZDS offering other relationships, like Compaq and Citizen, soon followed. At this time the quality of Japanese engineering and manufacturing in conjunction with the strength of the dollar relative to the yen (typically about 130 Yen = $1) drove most brands to suppliers in Japan. Companies such as Sanyo, Tottori Sanyo, Citizen, and Casio were all heavily involved in this business as OEMs. However, by the mid-1990s a weakening dollar and the rising viability of Taiwanese OEMs such as Acer, Quanta, Compal, Twinhead, and Chicony lead the supply base to rapidly shift from Japan to Taiwan. Additionally, brands which were more nimble and relied less on internal engineering such as Gateway, Dell and Micron began to rise quickly to leadership positions. Combinations such as Dell/Compal and Gateway/Quanta eventually became powerhouse partnerships and greatly contributed to the prominence of Taiwanese OEMs as the center of PC manufacturing from about 1995 onward.

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 mebibyte 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 grayscale backlit displays with CGA resolution.


The Macintosh Portable, Apple's first attempt at a battery-powered computerThe 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).

The summer of 1995 was a significant turning point in the history of notebook computing. In August of that year Microsoft introduced Windows 95. It was the first time that Microsoft had placed much of the power management control in the operating system. Prior to this point each brand used custom BIOS, drivers and in some cases, ASICs, to optimize the battery life of its machines. This move by Microsoft was controversial in the eyes of notebook designers because it greatly reduced their ability to innovate; however, it did serve its role in simplifying and stabilizing certain aspects of notebook design. Windows 95 also ushered in the importance of the CD-ROM drive in mobile computing and initiated the shift to the Intel Pentium processor as the base platform for notebooks. The Gateway Solo was the first notebook introduced with a Pentium processor and a CD-ROM. By also featuring a removable hard disk drive and floppy drive it was the first three-spindle (optical, floppy, and hard disk drive) notebook computer. The Gateway Solo was extremely successful within the consumer segment of the market. In roughly the same time period the Dell Latitude, Toshiba Satellite, and IBM Thinkpad were reaching great success with Pentium-based two-spindle (hard disk and floppy disk drive) systems directed toward the corporate market.


A 1997 Micron laptopAs 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 cadmium or NiCD, then 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 386SL processor, designed for the specific power needs of laptops, marked the point at which laptop needs were included in CPU design. The 386SL integrated a 386SX core with a memory controller and this was paired with an I/O chip to create the SL chipset. It was more integrated than any previous solution although its cost was higher. It was heavily adopted by the major notebook brands of the time. Intel followed this with the 486SL chipset which used the same architecture. However, Intel had to abandon this design approach as it introduced its Pentium series. Early versions of the mobile Pentium required TAB mounting (also used in LCD manufacturing) and this initially limited the number of companies capable of supplying notebooks. However, Intel did eventually migrate to more standard chip packaging. One limitation of notebooks has always been the difficulty in upgrading the processor which is a common attribute of desktops. Intel did try to solve this problem with the introduction of the MMC for mobile computing. The MMC was a standard module upon which the CPU and external cache memory could sit. It gave the notebook buyer the potential to upgrade his CPU at a later date, eased the manufacturing process some, and was also used in some cases to skirt U.S. import duties as the CPU could be added to the chassis after it arrived in the U.S. Intel stuck with MMC for a few generations but ultimately could not maintain the appropriate speed and data integrity to the memory subsystem through the MMC connector.
Improved liquid crystal displays, in particular active-matrix TFT (Thin-Film Transistor) LCD technology. Early laptop screens were black and white, blue and white, or grayscale, STN (Super Twist Nematic) passive-matrix LCDs prone to heavy shadows, ghosting and blurry movement (some portable computer screens were sharper monochrome plasma displays, but these drew too much current to be powered by batteries). Color STN screens were used for some time although their viewing quality was poor. By about 1991 , two new color LCD technologies hit the mainstream market in a big way; Dual STN and TFT. The Dual STN screens solved many of the viewing problems of STN at a very affordable price and the TFT screens offered excellent viewing quality although initially at a steep price. DSTN continued to offer a significant cost advantage over TFT until the mid-90s before the cost delta dropped to the point that DSTN was no longer used in notebooks. Improvements in production technology meant displays became larger, sharper, had higher native resolutions, faster response time 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. The 3.5" HDD was created initially as a response to the needs of notebook designers that needed smaller, lower power consumption products. With continuing pressure to shrink the notebook size even further, the 2.5" HDD was introduced.
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.

[edit] Parts
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Hard disk from a Dell LatitudeMost 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 (formerly PCMCIA) or ExpressCard expansion bay for expansion cards. 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, Celeron, Intel Core and Intel Core 2) and from AMD (Athlon, Turion 64, and Sempron) and also from VIA (C3 and C7-M). 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 were 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.
Some parts for a modern laptop have no corresponding part in a desktop computer:

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 became common laptop accessories in the early 1990s. They typically were quite large and offered 3.5" and 5.25" storage bays, one to three expansion slots (typically AT style), and a host of connectors. The mating between the laptop and docking station was typically through a large, high-speed, proprietary connector. 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 to additional storage and expansion slots became less critical because of the high integration inside the laptop itself, the emergence of the Port Replicator as a major accessory commenced. The Port Replicator was often a passive device that simply mated to the connectors on the back of the notebook and allowed the user to quickly connect their laptop so VGA, PS/2, RS-232, etc. devices were instantly attached. As higher speed ports like USB and Firewire became commonplace, the Port Replication was accomplished by a small cable connected to one of the USB 2.0 or FireWire ports on the notebooks. Wireless Port Replicators followed.
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.
A pointing stick or touchpad is used to control the position of the cursor on the screen. The pointing stick is usually a rubber dot that is located between the G, H and B keys on the laptop keyboard. To navigate the cursor, pressure is applied in the direction intended to move. The touchpad is touch-sensitive and the cursor can be navigated by moving the finger on the pad.

[edit] Disadvantages

[edit] Standardization issues
While there are accepted world standards of form factors for all the peripherals and add-in PC cards used in the desktop computers, there are still no firm worldwide standards relating to today's laptops' form factors internally, such as supply of electric voltage, motherboard layouts, internal adapters used in connecting the hard disk, optical drive, LCD cable, keyboard and floppy drive to the main board. Most affected by this are uneducated users, especially if they attempt to connect their laptops with incompatible hardware or power adapters.

Laptops are more complex than simple-to-use consumer electronics. A large number of different parts with similar functions may cause some difficulties to repair people, as they have to familiarize themselves with different sets of hardware, but this is part of the job in a specialized trade.


[edit] Compatibility issues
Any current compatibility problems in the laptop trade are reflective to the early era of personal computers, when there were many different manufacturers, each and every one of them having their own systems and incompatibility was more a norm.

Some mostly internal or proprietary parts made by laptop producers aren't interchangeable with other manufacturers' products, so that the same manufacturer's components are used with the laptop they produced. Some of the reasons for this are to ensure product stability, prolong product lifetime, to avoid dubious warranty issues and to protect computer beginners from harming their machines.

A significant point to note is that the vast majority of laptops on the market are manufactured by a small handful of ODMs.[3] The ODM matters more than the OEM. Major relationships include:

Compal sells to Toshiba, HP/Compaq, Acer, and Dell
Quanta sells to HP/Compaq, Dell, Toshiba, Sony, Fujitsu, Acer, NEC, and IBM
Winstron sells to HP/Compaq, Dell, IBM, NEC, and Acer
Arima sells to HP/Compaq, NEC, and Dell
Uniwill/ECS sells to IBM, Fujitsu, and Dell
Asus sells to Apple (iBook), Sony, and Samsung
Inventec sells to HP/Compaq, Toshiba, and BenQ
To compensate, some manufacturers have and have had product lines where they have refrained from including some internal hardware in their products by adding in the number of standard hardware outlets and ports, thereby letting users choose their own hardware that they can connect.

In terms of hardware components standardization, PCMCIA/CardBus has proved to be a rather enduring standard. Older laptops lacking a USB port can have a PCMCIA USB/FireWire adapter plugged in. Modern adapters have two to four USB ports or they can be USB/Firewire combo adapters. Thus, such compatibility problems with getting hardware and peripherals connected has nowadays become a non-issue.


[edit] Free software
In some situations, users may have to pay for the additional cost that is wielded by some laptop manufacturers, by using their proprietary hardware extensions and including internal hardware that lacks documentation that would be instrumental in developing free software drivers.

Users of free and open-source software (FOSS) are more affected by this, as internal laptop hardware is not as easy or downright impossible to replace (when hardwired) than with stock desktop PC's. Aside from the Microsoft tax, if internal laptop hardware is lacking drivers, free or otherwise, for FOSS operating systems (such as Linux and *BSD), it is of little use to them and essentially deadweight.

Therefore, users should first carefully research the desired products to avoid this and choose manufacturers that are known for favoring free and open source software.


[edit] Naming conventions
Naming of features and parts used and/or their categories also differs from manufacturer to manufacturer, such as "system board" used by IBM and "motherboard" used by Compaq, "display cable", "LCD cable", "flexi-cable" are the terms used by the general public refer to the cable connecting the external display to the main board for transferring the digital signal (actual signalling is more or less standardized, though). Hardware problems with cables can be solved by correctly buying the right cables in the first place. Having some cable adapters is handy when dealing with hardware that was manufactured in different time periods by different standards.

The palm rest is called "palm rest" by Dell[4], the "keyboard bezel" by IBM[5] and the "upper CPU cover" by Compaq and HP.[6]


[edit] Upgradeability
Laptops' upgradeability is severely limited, both for technical and economic reasons. As of 2006, there is no industry-wide 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 (motherboard), and thus upgrades often require using external ports, card slots, or wireless peripherals. Other components, such as RAM modules, hard drives, and batteries are typically user-upgradeable.

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 than the end-user, as few manufacturers try new CPUs in last year's laptop model with an eye toward selling upgrades rather than new laptops. In many other laptops, the CPU is soldered and non-replaceable. [7]

Many laptops also include an internal MiniPCI slot, often occupied by a WiFi or Bluetooth card, but as with the CPU, the internal slot is often 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 after-market.


[edit] Performance

A modern mid-range HP Laptop. It is best used as a desktop replacementFor a given price range (and manufacturing base), laptop computational power has traditionally trailed that of desktops. This is partly due to most laptops sharing RAM between the program memory and the graphics adapter. By virtue of their usage goals, laptops prioritize energy efficiency and compactness over absolute performance. Desktop computers and their modular components are built to fit much bigger standard enclosures, along with the expectation of AC line 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 the required performance. 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.

With the advent of dual-core processors and perpendicular recording, laptops are beginning to close the performance gap with PCs. Intel's Core 2 line of processors is efficient enough to be used in portable computers, and many manufacturers such as Apple Computer and Dell are building Core 2 based laptops. Also, many high end laptop computers feature mobility versions of graphics cards, eliminating the performance losses associated with integrated graphics.


[edit] Health issues

Laptop coaster preventing heating of lap and improving laptop airflow.A study by State University of New York researchers says heat generated from laptops can significantly elevate the temperature of the scrotum, potentially putting sperm count at risk. The study, which included more than two dozen men ages 13 to 35, found that the sitting position required to balance a laptop can raise scrotum temperature by as much as 2.1°C. Heat from the laptop itself can raise the temperature by another 0.7°C, bringing the potential total increase to 2.8°C. Heating of the scrotum is known to cause temporary sterility in men. [8]


[edit] Security
Laptops are generally prized targets of theft, and theft of laptops can lead to more serious problems such as identity theft from stolen credit card numbers.[9] Most laptops have a Kensington security slot to chain the computer to a desk with a third party security cable.


[edit] Major brands and manufacturers
Acer - TravelMate, Extensa, Ferrari and Aspire
Acorn Computers - Deskbook, Desknote and Solonote
Advent
Alienware - Area 51m, Alienware Sentia and Aurora m
Apple - Macintosh Portable, PowerBook, PowerBook Duo, PowerBook G3, PowerBook G4, iBook, iBook G4, MacBook, and MacBook Pro
ASUS
Averatec
BenQ
Clevo
Compaq - EVO, Armada, LTE, and Presario
Dell - Inspiron, Latitude, Precision and XPS
ECS
Evesham Technology
Falcon Northwest - DR6800, TL2
Fujitsu Siemens - Lifebook, FMV - BiBlo, Amilo
Gateway
Gericom
HCL
Hewlett-Packard - HP Pavilion and HP Omnibook
Hypersonic
Hyundai
IBM - see Lenovo
Lenovo - ThinkPad and 3000 series
LG - XNOTE
LinuxCertified - Linux laptop
MDG Computers
Medion
Micro-Star International (MSI)
NEC - VERSA, LaVie
Packard Bell - EasyNote
Panasonic - Toughbook, Let's Note (available in Japan only)
Samsung - Sens
Seanix - Seanix
Sharp - Mebius
Sony - VAIO, C series, FJ Series: ,N series, Sz series, FZ series, Ar series
Toshiba - Dynabook, Equium, Portege, Tecra, Satellite, Qosmio, Libretto
Vigor Gaming - Atlantis, Augustus, Artorius, and Aegis
Voodoo PC - Envy
Zenith



[edit] See also