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AMD Lets Cat out of Bag With Puma Launch

2008-06-04T00:22:00.000-07:00

AMD Lets Cat out of Bag With Puma Launch

Advanced Micro Devices (AMD) will uncage its Puma laptop chip platform at events in Taipei and Paris on Wednesday. It's the first new laptop platform the microprocessor manufacturer has developed since it acquired graphics chip specialist ATI -- and perhaps the last such platform in which central processor and graphics processor will be separate components.

"The next generation is all about graphics and throughput," said Leslie Sobon, AMD's worldwide director of product marketing. "Nobody needs to open Word and Excel documents faster," she said, so instead AMD is focusing on speeding up video and video games performance for home users.

There's no "Puma inside" logo to promote it, though: Customers looking for the latest chips will need to check that they're getting a laptop with an AMD Turion X2 Ultra processor (the "Ultra" is new), the 780 chipset and an ATI Mobility Radeon HD 3000 Series graphics chip -- or maybe two, if they want to profit from one of the platform's power-saving, performance-enhancing features: hybrid graphics.

Some of the graphics chips that work with the Turion X2 Ultra are already on the market, but AMD is adding a discrete graphics chip at the high end of the range, the 3870.

Of the 100 or so notebook designs being readied using the new platform, around one-third will use discrete graphics chips, said Sobon. Those models may appeal more to Europeans: Around half of laptops sold in Europe include discrete graphics chips, which use their own memory rather than sharing system resources. In the U.S. about one-fifth of laptops ship with these chips.

"Europe understands the value of discrete graphics, the U.S. not so much," she said. "If you have [US]$50 to $100 more to spend on a laptop, those dollars are better spent on discrete graphics than on faster clock speed."

Companies building laptops with Puma components include Acer, Asus, Dell, Fujitsu-Siemens, HP, NEC and Toshiba, she said. But there'll be no Puma notebook platform from Lenovo or Apple: "Of course" we tried to sell the processors to Apple, said Sobon, noting that the company does buy ATI graphics chips from AMD.

One-third of those laptop designs have 15-inch screens, but there are also models with screens as large as 18 inches or as small as 12 inches. "There are no ultraportables," said Sobon.

The first crop of Puma-based laptops will be missing one of the more interesting features of the platform: PowerXpress. This can toggle between using an integrated graphics chip to save power and a discrete chip for better performance, all without rebooting the machine. The first machines to feature it will appear late in the third quarter, said Sobon.

The Turion X2 Ultra processor has other power-saving capabilities: Power to either of its dual cores, or the integrated memory controller, can be reduced or cut entirely, depending on its level of activity. It can also offload the video encoding and decoding activities involved in playing DVDs or editing videos to the graphics chip, reducing power consumption.

Analyst expectations for Puma are high.

"Puma is what is going to allow AMD to improve its competitive position against Intel," said Dean McCarron, principal analyst at Mercury Research.

Intel is leaving AMD little room to maneuver, though: "It's keeping a pretty strong pace on platform rollouts," said McCarron.

And although problems with some chipset components of Intel's upcoming Centrino 2 mobile platform, code-named Montevina, have delayed its launch a little, "There really isn't a big gap between the platforms," he said.

With the Centrino brand, Intel made a big deal of its own wireless capabilities, but AMD thinks it can do better by allowing laptop designers to choose their favorite third-party wireless products. "We are open in our wireless solutions," said Sobon. As a result, AMD products have "2.5 times the throughput and range that they do," he said.

AMD stands to gain little from moving into the wireless chip market, according to McCarron: Design costs are high, because the chips are complex and yet relatively inexpensive. "There's not a lot of profit for AMD to be chasing there," he said.

McCarron doesn't expect the launch of Puma to have much effect on notebook pricing. "As technology gets improved, components get replaced at the same price point."

Taken from : http://www.pcworld.com

Intel Doubles Storage on SSD Drives

2008-06-04T00:19:00.000-07:00

Intel on Tuesday introduced an 8G-byte solid-state storage drive and said it would make a 16G-byte solid-state drive available in the fourth quarter of this year.

The Intel Z-P230 PATA 8G-byte SSD is small enough to use with sub-notebooks and ultra-low-cost notebooks, Intel said. The drive, which comes in the form of a chip, is four times smaller than a traditional 1.8-inch hard disk drive and weighs 10 grams.

SSDs have no moving parts, making them more rugged than hard drives, according to Intel. SSDs also consume less power than hard drives, giving laptops more battery life. Intel is aiming this product at Netbooks and Nettops, a brand of low-cost PCs launched by Intel earlier this year that will carry the company's low-cost Atom processor.

The announcement was made at the Computex trade show in Taipei.

The drive will be available for US$45 in units of 1,000 in the third quarter of this year. Intel declined comment on the pricing for the 16G-byte SSD.

The company last month announced it would double the density of its 16G-byte drives to 32G-byte drives that will enable on-board storage capacity of up to 256G bytes of storage in a 1.8-inch form factor. The drives will be linked on-board via a standard PATA (parallel advanced technology attachment) interface.

The company will ship samples of the 32G-byte drive starting in June, with mass production expected in the second half of this year. Intel didn't comment on when it expects to formally ship the 32G-byte drive.

Intel introduced SSD drives late last year, announcing 2G-byte and 4G-byte drives. At the time, Intel said it would grow SSD storage modules to 64G bytes in two years

Taken from : http://www.pcworld.com

What Is a Hacker?

2008-05-28T15:12:00.002-07:00

The Jargon File contains a bunch of definitions of the term ‘hacker’, most having to do with technical adeptness and a delight in solving problems and overcoming limits. If you want to know how to become a hacker, though, only two are really relevant.

There is a community, a shared culture, of expert programmers and networking wizards that traces its history back through decades to the first time-sharing minicomputers and the earliest ARPAnet experiments. The members of this culture originated the term ‘hacker’. Hackers built the Internet. Hackers made the Unix operating system what it is today. Hackers run Usenet. Hackers make the World Wide Web work. If you are part of this culture, if you have contributed to it and other people in it know who you are and call you a hacker, you're a hacker.

The hacker mind-set is not confined to this software-hacker culture. There are people who apply the hacker attitude to other things, like electronics or music — actually, you can find it at the highest levels of any science or art. Software hackers recognize these kindred spirits elsewhere and may call them ‘hackers’ too — and some claim that the hacker nature is really independent of the particular medium the hacker works in. But in the rest of this document we will focus on the skills and attitudes of software hackers, and the traditions of the shared culture that originated the term ‘hacker’.

There is another group of people who loudly call themselves hackers, but aren't. These are people (mainly adolescent males) who get a kick out of breaking into computers and phreaking the phone system. Real hackers call these people ‘crackers’ and want nothing to do with them. Real hackers mostly think crackers are lazy, irresponsible, and not very bright, and object that being able to break security doesn't make you a hacker any more than being able to hotwire cars makes you an automotive engineer. Unfortunately, many journalists and writers have been fooled into using the word ‘hacker’ to describe crackers; this irritates real hackers no end.

The basic difference is this: hackers build things, crackers break them.

If you want to be a hacker, keep reading. If you want to be a cracker, go read the alt.2600 newsgroup and get ready to do five to ten in the slammer after finding out you aren't as smart as you think you are. And that's all I'm going to say about crackers.

Taken From : http://www.catb.org/~esr/faqs/hacker-howto.html#what_is

Optical mark recognition

2008-05-28T15:12:00.001-07:00

Optical mark recognition is the process of capturing data by contrasting reflectivity at predetermined positions on a page. By shining a beam of light onto the document the scanner is able to detect a marked area because it reflects less light than an unmarked surface. Some OMR devices use forms which are preprinted onto 'Transoptic' paper and measure the amount of light which passes through the paper, thus a mark on either side of the paper will reduce the amount of light passing through the paper.

It is generally distinguished from optical character recognition by the fact that a recognition engine is not required. That is, the marks are constructed in such a way that there is little chance of not reading the marks correctly. This does require the image to have high contrast and an easily-recognizable or irrelevant shape.

One of the most familiar applications of optical mark recognition is the use of #2 (HB in Europe) pencil bubble optical answer sheets in multiple choice question examinations. Students mark their answers, or other information, by darkening circles marked on a pre-printed sheet. Afterwards the sheet is automatically graded by a scanning machine. In most European countries, a horizontal or vertical 'tick' in a rectangular 'lozenge' is the most commonly used type of OMR form, the most familiar application being the UK National lottery form. Lozenge marks are a later technology and have the advantage of being easier to mark and easier to erase. The large 'bubble' marks are legacy technology from the very early OMR machines that were so insensitive a large mark was required for reliability. In most Asian countries, a special marker is used to fill in an optical answer sheet. Students, likewise mark answers or other information via darkening circles marked on a pre-printed sheet. Then the sheet is automatically graded by a scanning machine.

Another example of OMR is the recognition of scannable bar codes.

Recent improvements in OMR have led to various kinds of two dimensional bar codes called matrix codes. For example, United Parcel Service (UPS) now prints a two dimensional bar code on every package. The code is stored in a grid of black-and-white hexagons surrounding a bullseye-shaped finder pattern. These images include error-checking data, allowing for extremely accurate scanning even when the pattern is damaged.
Most of today's OMR applications work from mechanically generated images like bar codes. A smaller but still significant number of applications involve people filling in specialized forms. These forms are optimized for computer scanning, with careful registration in the printing, and careful design so that ambiguity is reduced to the minimum possible. Due to its extremely low error rate, low cost and ease-of-use, OMR is a popular method of tallying votes

Taken From : http://en.wikipedia.org/wiki/Optical_mark_recognition

History of Wi-Fi

2008-05-05T22:40:00.000-07:00

History

Wi-Fi uses both single carrier direct-sequence spread spectrum radio technology (part of the larger family of spread spectrum systems) and multi-carrier OFDM (Orthogonal Frequency Division Multiplexing) radio technology. The regulations for unlicensed spread spectrum enabled the development of Wi-Fi, its onetime competitor HomeRF, Bluetooth, and many other products such as some types of cordless telephones.

Unlicensed spread spectrum was first made available in the US by the Federal Communications Commission in 1985 and these FCC regulations were later copied with some changes in many other countries enabling use of this technology in all major countries.[12] The FCC action was proposed by Michael Marcus of the FCC staff in 1980 and the subsequent regulatory action took 5 more years. It was part of a broader proposal to allow civil use of spread spectrum technology and was opposed at the time by main stream equipment manufacturers and many radio system operators.[13]

The precursor to Wi-Fi was invented in 1991 by NCR Corporation/AT&T (later Lucent & Agere Systems) in Nieuwegein, the Netherlands. It was initially intended for cashier systems; the first wireless products were brought on the market under the name WaveLAN with speeds of 1 Mbit/s to 2 Mbit/s. Vic Hayes, who held the chair of IEEE 802.11 for 10 years and has been named the 'father of Wi-Fi,' was involved in designing standards such as IEEE 802.11b, and 802.11a.

Taken from : http://en.wikipedia.org/wiki/Wi-Fi

About Wi-Fi

2008-05-05T22:38:00.000-07:00

Wi-Fi

Wi-Fi (IPA: /ˈwaɪfaɪ/) is the common name for a popular wireless technology used in home networks, mobile phones, video games and more. Wi-Fi is supported by nearly every modern personal computer operating system and most advanced game consoles.

Purpose

The purpose of Wi-Fi is simple: Hide complexity by enabling wireless access to applications and data, media and streams. The main aims of Wi-Fi are:

* enable access to information easily
* ensure compatibility and coexistence
* get rid of cabling and wiring
* get rid of switches, adapters, plugs and connectors.

taken from : http://en.wikipedia.org/wiki/Wi-Fi

Linux

2008-04-25T02:53:00.001-07:00

Linux

Tux, the penguin, mascot of Linux
OS family Unix-like
Kernel type Monolithic kernel
License GNU General Public License and others
Working state Current

Linux (commonly pronounced IPA: /ˈlɪnəks/ in English; variants exist[1]) is a Unix-like computer operating system. Linux is one of the most prominent examples of free software and open source development: typically all underlying source code can be freely modified, used, and redistributed by anyone.[2]

The name "Linux" comes from the Linux kernel, started in 1991 by Linus Torvalds. The system's utilities and libraries usually come from the GNU operating system, announced in 1983 by Richard Stallman. The GNU contribution is the basis for the alternative name GNU/Linux.[3]

Predominantly known for its use in servers, Linux is supported by corporations such as Dell, Hewlett-Packard, IBM, Novell, Oracle Corporation, Red Hat, and Sun Microsystems. It is used as an operating system for a wide variety of computer hardware, including desktop computers, supercomputers,[4] video game systems, such as the PlayStation 2 and PlayStation 3, several arcade games, and embedded devices such as mobile phones, routers, and stage lighting systems.

Taken from : http://en.wikipedia.org/wiki/Linux

Microsoft Windows

2008-04-25T02:47:00.000-07:00

Microsoft Windows

Microsoft Windows is the name of several families of software operating systems by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces (GUIs).[1] Microsoft Windows came to dominate the world's personal computer market, overtaking Mac OS, which had been introduced previously. At the 2004 IDC Directions conference, IDC Vice President Avneesh Saxena stated that Windows had approximately 90% of the client operating system market.[2] The most recent client version of Windows is Windows Vista. The current server version of Windows is Windows Server 2008.

Taken from : http://en.wikipedia.org/wiki/Microsoft_Windows

About Operating System

2008-04-25T02:44:00.001-07:00

Operating system

An operating system (OS) is a software that manages computer resources and provides programmers/users with an interface used to access those resources. An operating system processes system data and user input, and responds by allocating and managing tasks and internal system resources as a service to users and programs of the system. An operating system performs basic tasks such as controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating computer networking and managing files. Operating systems can be found on almost anything made with integrated circuits, such as personal computers, internet servers, cellphones, music players, routers, switches, wireless access points, network storage, game consoles, digital cameras, sewing machines and telescopes.

In most cases, the operating system is not the first code to run on the computer at startup (boot) time. The initial code executing on the computer is usually loaded from firmware, which is stored in Flash ROM. This is sometimes called the BIOS or boot ROM. The firmware loads and executes the operating system kernel (usually from disk, sometimes over the network), and is usually responsible for the first graphics or text output the user sees onscreen.

Common contemporary desktop OSes are Linux, Mac OS X, Microsoft Windows and Solaris. Windows is most popular on desktops while Linux is most popular in server environments. Linux, Mac OS X and MS Windows all have server and personal variants. With the exception of Microsoft Windows, the designs of each of the aforementioned OSs were inspired by, or directly inherited from, the Unix operating system. Unix was developed at Bell Labs beginning in the late 1960s and spawned the development of numerous free and proprietary operating systems.

Taken from : http://en.wikipedia.org/wiki/Operating_system

About Memory

2008-04-25T02:41:00.000-07:00

Computer data storage

Computer data storage, often called storage or memory, refers to computer components, devices, and recording media that retain digital data used for computing for some interval of time. Computer data storage provides one of the core functions of the modern computer, that of information retention. It is one of the fundamental components of all modern computers, and coupled with a central processing unit (CPU, a processor), implements the basic computer model used since the 1940s.

In contemporary usage, memory usually refers to a form of semiconductor storage known as random access memory (RAM) and sometimes other forms of fast but temporary storage. Similarly, storage today more commonly refers to mass storage - optical discs, forms of magnetic storage like hard disks, and other types slower than RAM, but of a more permanent nature. Historically, memory and storage were respectively called primary storage and secondary storage.

The contemporary distinctions are helpful, because they are also fundamental to the architecture of computers in general. As well, they reflect an important and significant technical difference between memory and mass storage devices, which has been blurred by the historical usage of the term storage. Nevertheless, this article uses the traditional nomenclature.

Taken from : http://en.wikipedia.org/wiki/Computer_storage

About Keyboard

2008-04-23T02:21:00.000-07:00

Keyboard

In computing, a keyboard is a peripheral partially modeled after the typewriter keyboard.

Physically, a keyboard is an arrangement of buttons, or keys. A keyboard typically has characters engraved or printed on the keys; in most cases, each press of a key corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence; other keys do not produce any symbol, but instead affect the operation of the computer or the keyboard itself. See input method editor.

A majority of all keyboard keys produce letters, numbers or signs (characters) that are appropriate for the operator's language. Other keys can produce actions when pressed, and other actions are available by the simultaneous pressing of more than one action key.

Taken from : http://en.wikipedia.org/wiki/Computer_keyboard

About Mouse

2008-04-23T00:44:00.000-07:00

Mouse

In computing, a mouse (plural mice, mouse devices, or mouses) is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of a small case, held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features can add more control or dimensional input. The mouse's motion typically translates into the motion of a pointer on a display, which allows for fine control of a Graphical User Interface.

The name mouse, originated at the Stanford Research Institute, derives from the resemblance of early models (which had a cord attached to the rear part of the device, suggesting the idea of a tail) to the common mouse.[1]

The first marketed integrated mouse — shipped as a part of a computer and intended for personal computer navigation — came with the Xerox 8010 Star Information System in 1981.

Taken from : http://en.wikipedia.org/wiki/Computer_mouse

History of Blue-Ray

2008-04-18T00:42:00.000-07:00

History

In 1998, commercial HDTV sets began to appear in the consumer market; however, there was no commonly accepted, inexpensive way to record or play HD content. In fact, there was no medium with the storage required to accommodate HD codecs, except JVC's Digital VHS and Sony's HDCAM.[5] Nevertheless, it was well known that using lasers with shorter wavelengths would enable optical storage with higher density. When Shuji Nakamura invented practical blue laser diodes, it was a sensation, although a lengthy patent lawsuit delayed commercial introduction.[6]

Taken from : http://en.wikipedia.org/wiki/Blu-ray_Disc

About Blue-Ray

2008-04-18T00:38:00.000-07:00

Blu-ray Disc

Reverse side of a Blu-ray Disc
Media type High-density optical disc
Encoding MPEG-2, MPEG-4 AVC (H.264), and VC-1
Capacity 25 GB (single layer)
50 GB (dual layer)
Read mechanism 405 nm laser, 1x@36 Mbit/s & 2x@72 Mbit/s & 4x@144 Mbit/s & 6x@216 Mbit/s[1] & 12x@432 Mbit/s
Developed by Blu-ray Disc Association
Usage Data storage, High-definition video and PlayStation 3 games

Blu-ray Disc (also known as Blu-ray or BD) is an optical disc storage media format. Its main uses are high-definition video and data storage. The disc has the same dimensions as a standard DVD or CD.

The name Blu-ray Disc is derived from the blue-violet laser used to read and write this type of disc. Because of its shorter wavelength (405 nm), substantially more data can be stored on a Blu-ray Disc than on the DVD format, which uses a red (650 nm) laser. A dual layer Blu-ray Disc can store 50 GB, almost six times the capacity of a dual layer DVD.

Blu-ray Disc was developed by the Blu-ray Disc Association, a group of companies representing consumer electronics, computer hardware, and motion picture production. The standard is covered by several patents belonging to different companies. As of March 2007, a joint licensing agreement for all the relevant patents had not yet been finalized.[2]

As of April 5, 2008, more than 530[3] Blu-ray Disc titles have been released in the United States, and more than 250 in Japan.

During the high definition optical disc format war, Blu-ray Disc competed with the HD DVD format. On February 19, 2008, Toshiba — the main company supporting HD DVD — announced it would no longer develop, manufacture and market HD DVD players and recorders,[4] leading almost all other HD DVD supporters to follow suit, effectively naming Blu-ray the victor of the format war.

taken from : http://en.wikipedia.org/wiki/Blu-ray_Disc

About DVD

2008-04-15T23:13:00.000-07:00

DVD (also known as "Digital Versatile Disc" or "Digital Video Disc" - see Etymology) is a popular optical disc storage media format. Its main uses are video and data storage. Most DVDs are of the same dimensions as compact discs (CDs) but store more than six times as much data.

Variations of the term DVD often describe the way data is stored on the discs: DVD-ROM has data which can only be read and not written, DVD-R and DVD+R can be written once and then function as a DVD-ROM, and DVD-RAM, DVD-RW, or DVD+RW hold data that can be erased and thus re-written multiple times. The wavelength used by standard DVD lasers is 650 nm[1], and thus has a red color.

DVD-Video and DVD-Audio discs respectively refer to properly formatted and structured video and audio content. Other types of DVDs, including those with video content, may be referred to as DVD-Data discs. As next generation High definition optical formats also use a disc identical in some aspects yet more advanced to a DVD, such as Blu-ray Disc, the original DVD is often given the retronym SD DVD (for standard definition).[2][3]

Taken from : http://en.wikipedia.org/wiki/DVD

History of DVD

2008-04-15T23:09:00.001-07:00

In 1993, two high-density optical storage standards were being developed; one was the MultiMedia Compact Disc, backed by Philips and Sony, and the other was the Super Density disc, supported by Toshiba, Time Warner, Matsushita Electric, Hitachi, Mitsubishi Electric, Pioneer, Thomson, and JVC. IBM's president, Lou Gerstner, acting as a matchmaker, led an effort to unite the two camps behind a single standard, anticipating a repeat of the costly videotape format war between VHS and Betamax in the 1980s.

Philips and Sony abandoned their MultiMedia Compact Disc and fully agreed upon Toshiba's SuperDensity Disc with only one modification, namely changing to EFMPlus modulation. EFMPlus was chosen as it has a great resilience against disc damage such as scratches and fingerprints. EFMPlus, created by Kees Immink, who also designed EFM, is 6% less efficient than the modulation technique originally used by Toshiba, which resulted in a capacity of 4.7 GB as opposed to the original 5 GB. The result was the DVD specification, finalized for the DVD movie player and DVD-ROM computer applications in December 1995.[4] In May 1997, the DVD Consortium was replaced by the DVD Forum, which is open to all other companies.

Taken from : http://en.wikipedia.org/wiki/DVD

History of Harddisk

2008-04-15T02:12:00.001-07:00

An IBM hard disk drive with the metal cover removed. The platters are highly reflective. A screwdriver bit is placed into one of six screws that clamp the stack of platters and spacers. In the center, below the screws and clamping plate, is the motor that spins the platters.
Date Invented: September 13, 1956
Invented By: An IBM team led by Rey Johnson
Connects to:

* Host adapter (on PCs often integrated into motherboard) via one of
o PATA (IDE) interface
o SATA interface
o SAS interface
o SCSI interface (popular on servers)
o FC interface (almost exclusively found on servers)

Market Segments:

* Desktop
* Mobile
* Enterprise
* Consumer
* Other/Miscellaneous

A hard disk drive (HDD), commonly referred to as a hard drive, hard disk or fixed disk drive,[1] is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces. Strictly speaking, "drive" refers to a device distinct from its medium, such as a tape drive and its tape, or a floppy disk drive and its floppy disk. Early HDDs had removable media; however, an HDD today is typically a sealed unit (except for a filtered vent hole to equalize air pressure) with fixed media.[2]

A HDD is a rigid-disk drive, although it is probably never referred to as such. By way of comparison, a so-called "floppy" drive (more formally, a diskette drive) has a disc that is flexible. Originally, the term "hard" was temporary slang, substituting "hard" for "rigid", before these drives had an established and universally-agreed-upon name. Some time ago, IBM's internal company term for an HDD was "file".

HDDs (introduced in 1956 as data storage for an IBM accounting computer[3]) were originally developed for use with computers, see History of hard disk drives.

In the 21st century, applications for HDDs have expanded beyond computers to include digital video recorders, digital audio players, personal digital assistants, digital cameras and video game consoles. In 2005 the first mobile phones to include HDDs were introduced by Samsung and Nokia.[4] The need for large-scale, reliable storage, independent of a particular device, led to the introduction of configurations such as RAID arrays, network attached storage (NAS) systems and storage area network (SAN) systems that provide efficient and reliable access to large volumes of data.
Contents

Taken from : http://en.wikipedia.org/wiki/Hard_disk

Human and computer interaction

2008-04-13T02:46:00.000-07:00

Human–computer interaction (HCI) is the study of interaction between people (users) and computers. It is often regarded as the intersection of computer science, behavioral sciences, design and several other fields of study. Interaction between users and computers occurs at the user interface (or simply interface), which includes both software and hardware, for example, general-purpose computer peripherals and large-scale mechanical systems, such as aircraft and power plants. The following definition is given by the Association for Computing Machinery[1]:

"Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them."

Because human-computer interaction studies a human and a machine in conjunction, it draws from supporting knowledge on both the machine and the human side. On the machine side, techniques in computer graphics, operating systems, programming languages, and development environments are relevant. On the human side, communication theory, graphic and industrial design disciplines, linguistics, social sciences, cognitive psychology, and human performance are relevant. And, of course, engineering and design methods are relevant.
HCI is also sometimes referred to as man–machine interaction (MMI) or computer–human interaction (CHI).

Taken From :
http://en.wikipedia.org/wiki/Human-computer_interaction

What is Proxy?

2008-04-09T21:00:00.000-07:00

Proxy server

In computer networks, a proxy server is a server (a computer system or an application program) which services the requests of its clients by forwarding requests to other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource, available from a different server. The proxy server provides the resource by connecting to the specified server and requesting the service on behalf of the client. A proxy server may optionally alter the client's request or the server's response, and sometimes it may serve the request without contacting the specified server. In this case, it would 'cache' the first request to the remote server, so it could save the information for later, and make everything as fast as possible.

A proxy server that passes all requests and replies unmodified is usually called a gateway or sometimes tunneling proxy.

A proxy server can be placed in the user's local computer or at specific key points between the user and the destination servers or the Internet.

Taken From :
http://en.wikipedia.org/wiki/Proxy_server

What is TCP/IP?

2008-04-09T20:57:00.000-07:00

Introduction to TCP/IP

Summary: TCP and IP were developed by a Department of Defense (DOD) research project to connect a number different networks designed by different vendors into a network of networks (the "Internet"). It was initially successful because it delivered a few basic services that everyone needs (file transfer, electronic mail, remote logon) across a very large number of client and server systems. Several computers in a small department can use TCP/IP (along with other protocols) on a single LAN. The IP component provides routing from the department to the enterprise network, then to regional networks, and finally to the global Internet. On the battlefield a communications network will sustain damage, so the DOD designed TCP/IP to be robust and automatically recover from any node or phone line failure. This design allows the construction of very large networks with less central management. However, because of the automatic recovery, network problems can go undiagnosed and uncorrected for long periods of time.

As with all other communications protocol, TCP/IP is composed of layers:

* IP - is responsible for moving packet of data from node to node. IP forwards each packet based on a four byte destination address (the IP number). The Internet authorities assign ranges of numbers to different organizations. The organizations assign groups of their numbers to departments. IP operates on gateway machines that move data from department to organization to region and then around the world.
* TCP - is responsible for verifying the correct delivery of data from client to server. Data can be lost in the intermediate network. TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received.
* Sockets - is a name given to the package of subroutines that provide access to TCP/IP on most systems.

Network of Lowest Bidders

The Army puts out a bid on a computer and DEC wins the bid. The Air Force puts out a bid and IBM wins. The Navy bid is won by Unisys. Then the President decides to invade Grenada and the armed forces discover that their computers cannot talk to each other. The DOD must build a "network" out of systems each of which, by law, was delivered by the lowest bidder on a single contract.

ipdept.gif

The Internet Protocol was developed to create a Network of Networks (the "Internet"). Individual machines are first connected to a LAN (Ethernet or Token Ring). TCP/IP shares the LAN with other uses (a Novell file server, Windows for Workgroups peer systems). One device provides the TCP/IP connection between the LAN and the rest of the world.

To insure that all types of systems from all vendors can communicate, TCP/IP is absolutely standardized on the LAN. However, larger networks based on long distances and phone lines are more volatile. In the US, many large corporations would wish to reuse large internal networks based on IBM's SNA. In Europe, the national phone companies traditionally standardize on X.25. However, the sudden explosion of high speed microprocessors, fiber optics, and digital phone systems has created a burst of new options: ISDN, frame relay, FDDI, Asynchronous Transfer Mode (ATM). New technologies arise and become obsolete within a few years. With cable TV and phone companies competing to build the National Information Superhighway, no single standard can govern citywide, nationwide, or worldwide communications.

The original design of TCP/IP as a Network of Networks fits nicely within the current technological uncertainty. TCP/IP data can be sent across a LAN, or it can be carried within an internal corporate SNA network, or it can piggyback on the cable TV service. Furthermore, machines connected to any of these networks can communicate to any other network through gateways supplied by the network vendor.
Addresses

Each technology has its own convention for transmitting messages between two machines within the same network. On a LAN, messages are sent between machines by supplying the six byte unique identifier (the "MAC" address). In an SNA network, every machine has Logical Units with their own network address. DECNET, Appletalk, and Novell IPX all have a scheme for assigning numbers to each local network and to each workstation attached to the network.

On top of these local or vendor specific network addresses, TCP/IP assigns a unique number to every workstation in the world. This "IP number" is a four byte value that, by convention, is expressed by converting each byte into a decimal number (0 to 255) and separating the bytes with a period. For example, the PC Lube and Tune server is 130.132.59.234.

An organization begins by sending electronic mail to Hostmaster@INTERNIC.NET requesting assignment of a network number. It is still possible for almost anyone to get assignment of a number for a small "Class C" network in which the first three bytes identify the network and the last byte identifies the individual computer. The author followed this procedure and was assigned the numbers 192.35.91.* for a network of computers at his house. Larger organizations can get a "Class B" network where the first two bytes identify the network and the last two bytes identify each of up to 64 thousand individual workstations. Yale's Class B network is 130.132, so all computers with IP address 130.132.*.* are connected through Yale.

The organization then connects to the Internet through one of a dozen regional or specialized network suppliers. The network vendor is given the subscriber network number and adds it to the routing configuration in its own machines and those of the other major network suppliers.

There is no mathematical formula that translates the numbers 192.35.91 or 130.132 into "Yale University" or "New Haven, CT." The machines that manage large regional networks or the central Internet routers managed by the National Science Foundation can only locate these networks by looking each network number up in a table. There are potentially thousands of Class B networks, and millions of Class C networks, but computer memory costs are low, so the tables are reasonable. Customers that connect to the Internet, even customers as large as IBM, do not need to maintain any information on other networks. They send all external data to the regional carrier to which they subscribe, and the regional carrier maintains the tables and does the appropriate routing.

New Haven is in a border state, split 50-50 between the Yankees and the Red Sox. In this spirit, Yale recently switched its connection from the Middle Atlantic regional network to the New England carrier. When the switch occurred, tables in the other regional areas and in the national spine had to be updated, so that traffic for 130.132 was routed through Boston instead of New Jersey. The large network carriers handle the paperwork and can perform such a switch given sufficient notice. During a conversion period, the university was connected to both networks so that messages could arrive through either path.
Subnets

Although the individual subscribers do not need to tabulate network numbers or provide explicit routing, it is convenient for most Class B networks to be internally managed as a much smaller and simpler version of the larger network organizations. It is common to subdivide the two bytes available for internal assignment into a one byte department number and a one byte workstation ID.

classb.gif

The enterprise network is built using commercially available TCP/IP router boxes. Each router has small tables with 255 entries to translate the one byte department number into selection of a destination Ethernet connected to one of the routers. Messages to the PC Lube and Tune server (130.132.59.234) are sent through the national and New England regional networks based on the 130.132 part of the number. Arriving at Yale, the 59 department ID selects an Ethernet connector in the C& IS building. The 234 selects a particular workstation on that LAN. The Yale network must be updated as new Ethernets and departments are added, but it is not effected by changes outside the university or the movement of machines within the department.
A Uncertain Path

Every time a message arrives at an IP router, it makes an individual decision about where to send it next. There is concept of a session with a preselected path for all traffic. Consider a company with facilities in New York, Los Angeles, Chicago and Atlanta. It could build a network from four phone lines forming a loop (NY to Chicago to LA to Atlanta to NY). A message arriving at the NY router could go to LA via either Chicago or Atlanta. The reply could come back the other way.

How does the router make a decision between routes? There is no correct answer. Traffic could be routed by the "clockwise" algorithm (go NY to Atlanta, LA to Chicago). The routers could alternate, sending one message to Atlanta and the next to Chicago. More sophisticated routing measures traffic patterns and sends data through the least busy link.

If one phone line in this network breaks down, traffic can still reach its destination through a roundabout path. After losing the NY to Chicago line, data can be sent NY to Atlanta to LA to Chicago. This provides continued service though with degraded performance. This kind of recovery is the primary design feature of IP. The loss of the line is immediately detected by the routers in NY and Chicago, but somehow this information must be sent to the other nodes. Otherwise, LA could continue to send NY messages through Chicago, where they arrive at a "dead end." Each network adopts some Router Protocol which periodically updates the routing tables throughout the network with information about changes in route status.

If the size of the network grows, then the complexity of the routing updates will increase as will the cost of transmitting them. Building a single network that covers the entire US would be unreasonably complicated. Fortunately, the Internet is designed as a Network of Networks. This means that loops and redundancy are built into each regional carrier. The regional network handles its own problems and reroutes messages internally. Its Router Protocol updates the tables in its own routers, but no routing updates need to propagate from a regional carrier to the NSF spine or to the other regions (unless, of course, a subscriber switches permanently from one region to another).
Undiagnosed Problems

IBM designs its SNA networks to be centrally managed. If any error occurs, it is reported to the network authorities. By design, any error is a problem that should be corrected or repaired. IP networks, however, were designed to be robust. In battlefield conditions, the loss of a node or line is a normal circumstance. Casualties can be sorted out later on, but the network must stay up. So IP networks are robust. They automatically (and silently) reconfigure themselves when something goes wrong. If there is enough redundancy built into the system, then communication is maintained.

In 1975 when SNA was designed, such redundancy would be prohibitively expensive, or it might have been argued that only the Defense Department could afford it. Today, however, simple routers cost no more than a PC. However, the TCP/IP design that, "Errors are normal and can be largely ignored," produces problems of its own.

Data traffic is frequently organized around "hubs," much like airline traffic. One could imagine an IP router in Atlanta routing messages for smaller cities throughout the Southeast. The problem is that data arrives without a reservation. Airline companies experience the problem around major events, like the Super Bowl. Just before the game, everyone wants to fly into the city. After the game, everyone wants to fly out. Imbalance occurs on the network when something new gets advertised. Adam Curry announced the server at "mtv.com" and his regional carrier was swamped with traffic the next day. The problem is that messages come in from the entire world over high speed lines, but they go out to mtv.com over what was then a slow speed phone line.

Occasionally a snow storm cancels flights and airports fill up with stranded passengers. Many go off to hotels in town. When data arrives at a congested router, there is no place to send the overflow. Excess packets are simply discarded. It becomes the responsibility of the sender to retry the data a few seconds later and to persist until it finally gets through. This recovery is provided by the TCP component of the Internet protocol.

TCP was designed to recover from node or line failures where the network propagates routing table changes to all router nodes. Since the update takes some time, TCP is slow to initiate recovery. The TCP algorithms are not tuned to optimally handle packet loss due to traffic congestion. Instead, the traditional Internet response to traffic problems has been to increase the speed of lines and equipment in order to say ahead of growth in demand.

TCP treats the data as a stream of bytes. It logically assigns a sequence number to each byte. The TCP packet has a header that says, in effect, "This packet starts with byte 379642 and contains 200 bytes of data." The receiver can detect missing or incorrectly sequenced packets. TCP acknowledges data that has been received and retransmits data that has been lost. The TCP design means that error recovery is done end-to-end between the Client and Server machine. There is no formal standard for tracking problems in the middle of the network, though each network has adopted some ad hoc tools.
Need to Know

There are three levels of TCP/IP knowledge. Those who administer a regional or national network must design a system of long distance phone lines, dedicated routing devices, and very large configuration files. They must know the IP numbers and physical locations of thousands of subscriber networks. They must also have a formal network monitor strategy to detect problems and respond quickly.

Each large company or university that subscribes to the Internet must have an intermediate level of network organization and expertise. A half dozen routers might be configured to connect several dozen departmental LANs in several buildings. All traffic outside the organization would typically be routed to a single connection to a regional network provider.

However, the end user can install TCP/IP on a personal computer without any knowledge of either the corporate or regional network. Three pieces of information are required:

1. The IP address assigned to this personal computer
2. The part of the IP address (the subnet mask) that distinguishes other machines on the same LAN (messages can be sent to them directly) from machines in other departments or elsewhere in the world (which are sent to a router machine)
3. The IP address of the router machine that connects this LAN to the rest of the world.

In the case of the PCLT server, the IP address is 130.132.59.234. Since the first three bytes designate this department, a "subnet mask" is defined as 255.255.255.0 (255 is the largest byte value and represents the number with all bits turned on). It is a Yale convention (which we recommend to everyone) that the router for each department have station number 1 within the department network. Thus the PCLT router is 130.132.59.1. Thus the PCLT server is configured with the values:

* My IP address: 130.132.59.234
* Subnet mask: 255.255.255.0
* Default router: 130.132.59.1

The subnet mask tells the server that any other machine with an IP address beginning 130.132.59.* is on the same department LAN, so messages are sent to it directly. Any IP address beginning with a different value is accessed indirectly by sending the message through the router at 130.132.59.1 (which is on the departmental LAN).

Taken from :
http://www.yale.edu/pclt/COMM/TCPIP.HTM

Seach Engine

2008-04-09T20:55:00.000-07:00

Search engines

Even before the World Wide Web, there were search engines that attempted to organize the Internet. The first of these was the Archie search engine from McGill University in 1990, followed in 1991 by WAIS and Gopher. All three of those systems predated the invention of the World Wide Web but all continued to index the Web and the rest of the Internet for several years after the Web appeared. There are still Gopher servers as of 2006, although there are a great many more web servers.

As the Web grew, search engines and Web directories were created to track pages on the Web and allow people to find things. The first full-text Web search engine was WebCrawler in 1994. Before WebCrawler, only Web page titles were searched. Another early search engine, Lycos, was created in 1993 as a university project, and was the first to achieve commercial success. During the late 1990s, both Web directories and Web search engines were popular—Yahoo! (founded 1995) and Altavista (founded 1995) were the respective industry leaders.

By August 2001, the directory model had begun to give way to search engines, tracking the rise of Google (founded 1998), which had developed new approaches to relevancy ranking. Directory features, while still commonly available, became after-thoughts to search engines.

Database size, which had been a significant marketing feature through the early 2000s, was similarly displaced by emphasis on relevancy ranking, the methods by which search engines attempt to sort the best results first. Relevancy ranking first became a major issue circa 1996, when it became apparent that it was impractical to review full lists of results. Consequently, algorithms for relevancy ranking have continuously improved. Google's PageRank method for ordering the results has received the most press, but all major search engines continually refine their ranking methodologies with a view toward improving the ordering of results. As of 2006, search engine rankings are more important than ever, so much so that an industry has developed ("search engine optimizers", or "SEO") to help web-developers improve their search ranking, and an entire body of case law has developed around matters that affect search engine rankings, such as use of trademarks in metatags. The sale of search rankings by some search engines has also created controversy among librarians and consumer advocates.

Taken from :
http://en.wikipedia.org/wiki/History_of_the_Internet

History of the Internet

2008-04-09T20:46:00.000-07:00

History of the Internet

Prior to the widespread inter-networking that led to the Internet, most communication networks were limited by their nature to only allow communications between the stations on the network, and the prevalent computer networking method was based on the central mainframe method. In the 1960s, computer researchers, J. C. R. Licklider and Robert W. Taylor pioneered calls for a joined-up global network to address interoperability problems. Concurrently, several research programs began to research principles of networking between separate physical networks, and this led to the development of Packet switching. These included Donald Davies (NPL), Paul Baran (RAND Corporation), and Leonard Kleinrock (MIT)'s research programs,

This led to the development of several packet switched networking solutions in the late 1960s and 1970s, including ARPANET, and X.25. Additionally, public access and hobbyist networking systems grew in popularity, including UUCP. They were however still disjointed separate networks, served only by limited gateways between networks. This led to the application of packet switching to develop a protocol for inter-networking, where multiple different networks could by joined together into a super-framework of networks. By defining a simple common network system, the Internet protocol suite, the concept of the network could be separated from its physical implementation. This spread of inter-network began to form into the idea of a global inter-network that would be called 'The Internet', and this began to quickly spread as existing networks were converted to become compatible with this. This spread quickly across the advanced telecommunication networks of the western world, and then began to penetrate into the rest of the world as it became the de-facto international standard and global network. However, the disparity of growth led to a Digital divide that is still a concern today.

Following commercialisation and introduction of privately run Internet Service Providers in the 1980s, and its expansion into popular use in the 1990s, the Internet has had a drastic impact on culture and commerce. This includes the rise of near instant communication by e-mail, text based discussion forums, the World Wide Web. Investor speculation in new markets provided by these innovations would also lead to the inflation and collapse of the Dot-com bubble, a major market collapse. But despite this, growth of the Internet continued, and still does.

Taken from :
http://en.wikipedia.org/wiki/History_of_the_Internet

How Bluetooth Works

2008-04-09T20:43:00.000-07:00

How Bluetooth Works

There are lots of different ways that electronic devices can connect to one another. For example:

* Component cables
* Electrical wires
* Ethernet cables
* WiFi
* Infrared signals

When you use computers, entertainment systems or telephones, the various pieces and parts of the systems make up a community of electronic devices. These devices communicate with each other using a variety of wires, cables, radio signals and infrared light beams, and an even greater variety of connectors, plugs and protocols.

The art of connecting things is becoming more and more complex every day. In this article, we will look at a method of connecting devices, called Bluetooth, that can streamline the process. A Bluetooth connection is wireless and automatic, and it has a number of interesting features that can simplify our daily lives.

The Problem
When any two devices need to talk to each other, they have to agree on a number of points before the conversation can begin. The first point of agreement is physical: Will they talk over wires, or through some form of wireless signals? If they use wires, how many are required -- one, two, eight, 25? Once the physical attributes are decided, several more questions arise:

* How much data will be sent at a time? For instance, serial ports send data 1 bit at a time, while parallel ports send several bits at once.

* How will they speak to each other? All of the parties in an electronic discussion need to know what the bits mean and whether the message they receive is the same message that was sent. This means developing a set of commands and responses known as a protocol.

Bluetooth offers a solution to the problem.

Taken from :
http://electronics.howstuffworks.com/bluetooth.htm

About Wireless Security

2008-04-09T20:41:00.000-07:00

Wireless security

Wireless security is the prevention of unauthorized access or damage to computers using wireless networks.

Wireless networks are very common, both for organizations and individuals. Many laptop computers have wireless cards pre-installed. The ability to enter a network while mobile has great benefits. However, wireless networking has many security issues.[1] Crackers have found wireless networks relatively easy to break into, and even use wireless technology to crack into wired networks.

The risks to users of wireless technology have increased as the service has become more popular. There were relatively few dangers when wireless technology was first introduced. Crackers had not yet had time to latch on to the new technology and wireless was not commonly found in the work place. However, there are a great number of security risks associated with the current wireless protocols and encryption methods, and in the carelessness and ignorance that exists at the user and corporate IT level.[2] Cracking methods have become much more sophisticated and innovative with wireless. Cracking has also become much easier and more accessible with easy-to-use Windows-based and Linux-based tools being made available on the web at no charge.

Some organizations that have no wireless access points installed do not feel that they need to address wireless security concerns. In-Stat MDR and META Group have estimated that 95% of all corporate laptop computers that were planned to be purchased in 2005 were equipped with wireless. Issues can arise in a supposedly non-wireless organization when a wireless laptop is plugged into the corporate network. A cracker could sit out in the parking lot and break in through the wireless card on a laptop and gain access to the wired network.

Taken From :
http://en.wikipedia.org/wiki/Wireless_security

History of Hotspot

2008-04-09T20:36:00.000-07:00

History

Wi-Fi hotspots were first proposed by Brett Stewart at the NetWorld+Interop conference in The Moscone Center in San Francisco in August 1993. Stewart did not use the term 'hotspot' but referred to public accessible wireless LANs. Stewart went on to found the companies PLANCOM in 1994 (for Public LAN Communications, which became MobileStar and then the HotSpot unit of T-Mobile USA.

The term 'HotSpot' may have first been advanced by Nokia about five years after Stewart first proposed the concept.

During the dot-com boom and subsequent bust in 2000, dozens of companies like WPMedia of the Rural Agriculture town of Kingstree SC had the notion that Wi-Fi could become the payphone for broadband. Although WPMedia Inc. invented, developed and patented United States Patent 7,035,281, . Retrieved on 20 September 2007 the concept of authenication, metering and billing for public domain WiFi use, the company's implementation never expanded beyond a few hundred square miles. The original notion was that users would pay for broadband access at hotspots and then expand to a completely roaming network. Although some companies like T-mobile, and Boingo have had some success with charging for access, over 90% of the over 300,000 hotspots offer free service to entice customers to their venue.[citation needed]

Both paid and free hotspots continue to grow. Wireless networks that cover entire cities, such as municipal broadband have mushroomed. MuniWireless reports that over 300 metropolitan projects have been started.

Many business models have emerged for hotspots. The final structure of the hotspot marketplace will ultimately have to consider the intellectual property rights of the early movers; portfolios of more than 1000 allowed and pending patent claims are held by some of these parties.

Taken from :
http://en.wikipedia.org/wiki/Hotspot_(Wi-Fi)

What is Hotspot?

2008-04-09T20:27:00.000-07:00

Hotspot (Wi-Fi)

A hotspot is a venue that offers Wi-Fi access. The public can use a laptop, WiFi phone, or other suitable portable device to access the Internet. Of the estimated 150 million laptops, 14 million PDAs, and other emerging Wi-Fi devices sold per year for the last few years, most include the Wi-Fi feature.

For venues that have broadband service, offering wireless access is as simple as purchasing one AP and connecting the AP with the gateway box.

Hotspots are often found at restaurants, train stations, airports, libraries, hotels, hospitals, coffee shops, bookstores, fuel stations, department stores, supermarkets and other public places. Many universities and schools have wireless networks in their campus.

taken from :
http://en.wikipedia.org/wiki/Hotspot_(Wi-Fi)

Online Computer Training For Free

2008-04-09T20:25:00.000-07:00

Online Computer Training For Free

So you're on a tight budget and at the same time you want some computer training, right? Nowadays there are a lot of options for people seeking better themselves through various training programs and certification classes. However, some of them just can’t afford to make some of these options possi

So you're on a tight budget and at the same time you want some computer training, right? Nowadays there are a lot of options for people seeking better themselves through various training programs and certification classes. However, some of them just can’t afford to make some of these options possible due to not enough cash flow. That is where free online computer training comes in to picture. Where else can you go and get enough information to teach yourself all about computers? You can learn from the most difficult HTML (hyper-text mark up language, used to build websites) to as simple as how to tear down and rebuild a CPU (central processing unit)?

If you can just plug into a free online computer training system or a set of resources available in almost all places, you can literally teach yourself almost anything. There are a variety of ways to go about this process, so let's start from the beginning. The very first thing you need to determine on your own what exactly you want to learn from your free online computer training, before you ever embark on your online adventure. Pick out your base subject, and then you can get started researching online sources for free training. For our examples, let's take the subject of HTML and see where we can get some free online computer training to learn HTML.

As the part of first step, let's get on a major search engine like Yahoo or Google and do a search for the term 'free HTML training' or 'free online computer training'. You will find quite a few results coming up in reference to these terms, but don't be fooled. Most of these won't really have free training, maybe just a free sample class or maximum two. Some of these won't even have anything free at all, they either buy an advertising slot or they develop their website in a way to show up higher in the results to get your attention. Remember, what you are looking for is a site that is truly going to give you free online computer training.

Sometimes you can see that the best results for free online computer training can come in the form of free forums or bulletin boards. For all those who are really new to the Internet, let's talk about them for a minute. Forums and bulletin boards are web pages that allow visitors to sign up as 'users', usually for free. Once you are registered with these sights, you can then post and respond to others on the forums or boards and ask questions. The specialty of these resources is that there are hundreds of websites out there covering almost all topics that can be imagined, especially the one’s dealing with computers. So for all those who are searching for an online free computer training this works like crazy. They also contain a great wealth of information from other users who have answered in return to the questions generally asked on the boards.

Another such website which contains one such free online computer training is e-zines and newsletters. You can as well do another research for the search term ‘free online computer training’ in conjunction with terms like e-zines and newsletters. Don’t worry as most of these too are free and you can subscribe for them either for a long or short time depending on what kind of materials are provided in the due course. Overall it can be said that where there is a will, there is a way, especially when it comes to free online computer training.

Article Source: http://www.1888articles.com/author-ian-traynor-5341.html

Privacy on The Internet

2008-04-09T20:17:00.000-07:00

Privacy on the Internet

Spyware is part of an overall public concern about privacy on the Internet. Experts in the field of Internet privacy have a consensus that Internet privacy doesn’t actually exist.

Spyware is part of an overall public concern about privacy on the Internet. Experts in the field of Internet privacy have a consensus that Internet privacy doesn’t actually exist.

It has been noted that spyware infects nearly 90% of Internet connected PC’s, with the main bulk of it coming from the installation of software. By installing certain software you could be placing media plugins, spyware, backdoor santa’s and Trojans on your PC; all of which are being placed there without your permission.

It is due to the increase in spyware that makes it important that you check and read all the disclosures, license agreement and privacy statements as sometimes the inclusion of unwanted spyware is documented within one of these. So just what happens to the information that is collected by companies through the use of spyware? It is believed that this information is potentially being sold and combined with other databases to build up profiles of individual web users for direct marketing purposes.

When spyware is present on your computer it performs certain behaviours such as advertising, collecting personal information or changing the configuration of your computer. Spyware has the ability to change your home page as well as adding additional components to your browser that you don’t need and don’t want. These changes can slow your computer down as well as being the cause of it crashing. Marketing firms often object to their programmes being referred to as spyware, which is why you may hear it being referred to as potentially unwanted programmes (PUP).

Spyware is made up by any technology that aids in gathering information about a person without their knowledge. This information that is gathered is then relayed to advertisers and other interested parties.

One example of spyware that most people will easily recognise is a cookie. This well known mechanism is used for storing data about an Internet user. If a website stores information about you in a cookie that you don’t know about it can be considered as being spyware.

Although spyware doesn’t steal personal information such as credit card numbers or you’re identify there is a real concern that this could happen in the future with yet more Internet and computer advancements. Spyware does however track your Internet use. It keeps a record of the products that you purchase and the type of websites that you visit and then uses this information to target advertisements at you based on its findings. For example if you have brought a number of comedy DVD’s or frequently visit sites to do with comedy, you may notice advertisements on many of the Internet pages that you visit will be based around comedy. The fact that this can actually happen is worrying; it demonstrates a real threat to our private lives and shines as an example of how easy it would be to use software such as spyware to gain confidential files and credit information.

There are a number of anti spyware solutions available to you, some of which are free, it is highly advised that you invest in an anti spyware solution as it can stop potential threats before it’s too late.

Article Source: http://www.1888articles.com/author-carolyn-clayton-1268.html

Computer Backup

2008-04-09T20:05:00.000-07:00

COMPUTER BACKUPS

Computer backup is so important to your computer that to ignore it is to risk its damnation. Computers require care and feeding. They require that you attend to their needs. If you don't, then they will most surely be sent to Hell. Computer hell is the place for computers without computer backup.

COMPUTERS AND HALLOWEEN, DO THEY MIX?

Computer backup is so important to your computer that to ignore it is to risk its damnation.

Computers require care and feeding. They require that you attend to their needs. If you don't, then they will most surely be sent to Hell.

Halloween means Hell. What! What do you mean that Halloween means Hell?

Well, if your computer is given the option of trick or treat, which will it accept? Will it accept the trick or the treat? What do you think?

Halloween is the time that computers are subject to tricks or treats. Did you know that more computers fail on Halloween than any other day of the year? That’s right. It’s true (smile). Your computer is in danger! Protect it. Do your computer backups.

Back to the Hell thing. Hell you say? Yep. Well, what do you mean by Hell?

Computer hell is the place for computers without computer backup. The failure to perform hard drive backup means that you are playing Russian Roulette with your data. Data needs your protection. Failure to protect your data may cause your home or business records to be sent to Hell.

Hell in this instance is for the records and files that cannot be resurrected. Resurrected you say, what does that mean?

It means that without computer backup as a source of salvation then the files can safely enjoy eternal oblivion. Oblivion you say, what does that mean? That means they are eternally lost from computer resurrection.

Is there any mercy for my precious files, you ask?

Why yes there is. Would like to know what the mercy for your files is? Yes! Yes! You say.

OK boys and girls listen carefully. The salvation, mercy, resurrection and redemption of your files lies in regular and consistent and persistent computer backup.

If you backup your computer consistently and persistently your files will be resurrected and saved from accidental deletion, hard drive failure and those nasty things like fire, flood, theft, earthquake, hurricanes, tornados and the like!

Computer backup is the key to your data's salvation!

Article Source: http://www.1888articles.com

Tips To Reduce Cost On A Notebook

2008-04-09T19:44:00.000-07:00

Tips To Reduce Cost On A Notebook

Whenever purchasing a notebook, it is important to know which features one should look for to get the most cost effective price. Learn more.

The technology used for manufacturing laptops and notebooks are advancing at a neck-breaking speed. Since companies are spending a fortune on the hi-tech research and development of the laptops, their prices can`t drop beyond a limit even if their sizes will. Laptops or notebooks are still being considered as high-end and expensive products. This article will guide you how to reduce you cost while buying a new notebook.

Here are some tips to consider for reducing the cost of that new notebook:

Overall Brand Quality:

Don`t compromise too much on this aspect. Bigger brands tend to offer better services. Hence, if you skimp on this aspect, then might have to take a big risk. However, there are some sites available on the internet that offers effective tools to find the best deal.

Processor:

It is always wise to pick the fasted processor. This is something you should never plan to upgrade later as doing so will require some addition cost. Compromising on this aspect is a bad idea as this has direct bearing on the speed of your work.

Memory:

You can save some money here because you can always upgrade the memory of your laptop as and when you need so. For example, getting 512 MB in the first memory slot (DIMM) will let you add an additional 512MB (in a second memory slot) later on for a total of 1GB, which means you will still make use of the 512MB that came with it.

Screen:

This is a personal consideration which is based on your use. Usually, older eyes prefer lower resolution of a less expensive screen. However, quite a few notebooks have 1 or 2 native resolutions that look good. But, these are high resolutions and most people over 40 find them difficult to read. Hence, to be on the safer side, you must compare before swipe your credit card.

Hard Drive:

If you want to skimp here, do so in terms of size but not speed. Insist on 7200 rpm and do not be influenced by varying views on this.

Video card:

Using a top video card makes sense when you are into graphics work, enjoying your favorite flicks or using Windows Vista with aero interface. Then you should consider including this top hardware feature seriously. However, if you are not doing any of them, then you might save a lot on this aspect.

Warranty:

Since repairing laptops are an expensive ball game, the longer the warranty, the more secured you are. Hence, if you think you will be able to skimp on this aspect, then it`s purely your call.

Operating system:

This is one area where you can substantially cut cost on you laptop. There is no point in paying extra for Windows Vista Ultimate if you are not going to use its features in your daily application. However, skimping down to Vista Basic would not be a good idea if you are planning to use the cool Aero interface. Hence, compare before you buy.

While buying a laptop, compare its cost with its performance. A laptop could cost you more if it is a high performer. However, you should consider the features you are going to use on a regular basis. It is pointless pay extra for the sake of features that are of little use to your purpose. Hence, consider your needs and pick the features you require to be there in your notebook. This will save you from hesitation and making potential errors while buying a laptop.

Article Source: http://www.1888articles.com/author-roberto-sedycias-1900.html

History of Networking

2008-04-09T19:42:00.000-07:00

History of Networking

The existence of today’s network is due to the continuous evolution in computer technology.

The first computers built in the 1950’s were very bulky and expensive and intended only for Government or University use. They were not intended for interactive work between business users, nor were they used in the packet-processing mode. As a rule, they were built on a mainframe basis - a powerful and reliable room sized server with a universal purpose. Users prepared punch cards containing data and program commands then transferred them to the computer service bureau. The operators then entered these cards into the computer, and the users received results after some waiting. The overall performance of this expensive process (called batch jobs) was crucial to the accurate performance of its users.

In the beginning of the 1960’s, simultaneously with the decrease of the prices of processors, business computer usage appeared, which took into account the interests of business needs and interactive multi-terminal systems for workload division. Several users shared the mainframe’s resources at a time. Each user could work individually with the mainframe through a terminal. The mainframe’s reaction time was so quick that the user almost did not notice the parallel work with other users. With this concept, the computing capacity remained centralized, but some of its functions became distributed. These multi-terminal systems became the ancestors of a new widely developing technology, “thin clients”, through which all information processing is carried out by one powerful computer, and the actual input/output operations performed by terminal stations having a minimal configuration of hardware and software.

In modern networks, the information processing is divided between either clients or servers. This model refers to the client – server relationship. The server is the one specialized powerful computer that provides the information that the client computers require. The client is the computer initiating the inquiry. This concept causes concern in relation to software sharing, as some OS’s require that one computer has to be the server, and all computers in the network called the clients. In addition, peer-to-peer networks exist where computer can be both client and/or server.171

The multi-terminal systems become a first step on the path of creating the modern network, however, the requirement that the terminals be connected with distant computers has gradually appeared, and the communications through telephone networks now comes through modems. (Even though the original meaning of “modem” meant modulator/demodulator, which is not performed in a straight digital connection, the devices used in xDSL and cable access are still called modems). The need for an automatic exchange of data had appeared. This mechanism relied on an exchange of files, synchronizing databases, and electronic mail between computers, (with the exception of the computer acting as the connection terminal). The entire network services mentioned became traditional needs.

In the beginning of the1970’s there was a lull in computer development172, and then large-scale integrated circuits appeared. (Up to this time, individual processors for each task were the norm, i.e. a processor for math functions, a processor for logic functions, etc.) The low cost and high functionality of the new integrated chips resulted in the creation of the mini-computer, which became the real competitor to the mainframe. Ten mini-computers carried out a task in parallel faster then one mainframe and had on top a lower overall cost.

Users now begin to realize that they would like to accept and transfer data with neighboring computers, which started the first stages of local networks. Companies thus began connecting users to each other, creating the first Peer-to Peer LANs. LAN (Local Area Network) is a group of workstations, PDA's (Personal Digital Assistant), terminals, printers, and other devices, incorporated into sharing a high-speed data medium that covers a relatively small geographic area.

http://www.certiguide.com/apfr/cg_apfr_HistoryofNetworking.htm

History of Laptop

2008-04-09T03:43:00.000-07:00

History of Laptop Computers - History modern laptop computerLeft - Modern Laptop Today

It is a little hard to determine what was the first portable or laptop computer, the first portable computers did not look like the book-sized and folding laptops that we are familiar with today, however, they were both portable and lapable, and lead to the development of notebook style laptops. I have outlined several potential firsts below and how each qualifies, many of the off-site links provide good photos of the computers that will let you see the progression in design.

The First Laptop? Maybe
Designed in 1979 by a Briton, William Moggridge, for Grid Systems Corporation, the Grid Compass was one fifth the weight of any model equivalent in performance and was used by NASA on the space shuttle program in the early 1980's. A 340K byte bubble memory lap-top computer with die-cast magnesium case and folding electroluminescent graphics display screen.

Gavilan Computer As The First Laptop?
Manny Fernandez had the idea for a well-designed laptop for executives who were starting to use computer. Fernandez, who started Gavilan Computer, promoted his machines as the first "laptop" computers in May 1983. Many historians consider the Gavilan as the first fully functional laptop computer.

The First Laptop Computer - Osborne 1
The computer considered by most historians to be the first true portable computer was the Osborne 1. Adam Osborne, an ex-book publisher founded Osborne Computer and produced the Osborne 1 in 1981, a portable computer that weighed 24 pounds and cost $1795. The Osborne 1 came with a five-inch screen, modem port, two 5 1/4 floppy drives, a large collection of bundled software programs, and a battery pack. The short-lived computer company was never successful. (second photo)

More History of Laptop Firsts

* Also released in 1981, was the Epson HX-20, a battery powered portable computer, with a 20-character by 4 line LCD display and a built-in printer.
* In January of 1982, Microsoft's Kazuhiko Nishi and Bill Gates begin discussions on designing a portable computer, based on using a new liquid crystal display or LCD screen. Kazuhiko Nishi later showed the prototype to Radio Shack who agree to manufacture the computer.
* In 1983, Radio Shack released the TRS-80 Model 100, a 4 lb. battery operated portable computer with a flat and more of a laptop design.
* In February 1984, IBM announced the IBM 5155 Portable Personal Computer.
* Three years later in 1986, Radio Shack released the improved and smaller TRS Model 200.
* In 1988, Compaq Computer introduces its first laptop PC with VGA graphics - the Compaq SLT/286.
* In 1989, NEC UltraLite was released, considered by some to be the first "notebook style" computer. It was a laptop size computer which weighed under 5 lbs. (second photo)
* In September 1989, Apple Computer released the first Macintosh Portable that later evolved into the Powerbook. (second photo)
* In 1989, Zenith Data Systems released the Zenith MinisPort, a 6-pound laptop computer. (more Zenith laptops)
* In October 1989, Compaq Computer released its first notebook PC, the Compaq LTE.
* In March 1991, Microsoft released the Microsoft BallPoint Mouse that used both mouse and trackball technology in a pointing device designed for laptop computers.
* In October 1991, Apple Computers released the Macintosh PowerBook 100, 140, and 170 - all notebook style laptops. (more on Powerbooks)
* In October 1992, IBM released its ThinkPad 700 laptop computer.
* In 1992, Intel and Microsoft release APM or the Advanced Power Management specification for laptop computers.
* In 1993, the first PDAs or Personal Digital Assistants are released. PDAs are pen-based hand-held computers.

Taken from :
http://inventors.about.com/library/inventors/bllaptop.htm

History of Camera

2008-04-08T23:17:00.000-07:00

The camera and photography are an important part of the communication history of the world. The history of the camera is indelibly linked to the understanding and development of optics. Optics is the study of physical properties of light in terms of generation and transmission and the use of lenses and mirrors to understand these properties. It is an important branch of physics. The basic principles of optics were known as early as the 4th century BC and Greek philosophers are credited with the development of this knowledge. 16th Century German scientist Johannes Kepler known for his study of astronomy and optics is often referred to as the founder of modern optics. He used the simple pinhole camera (invented many centuries before his time and known to Aristotle as early as 322 BC) to understand how pictures can be formed.

Early cameras of the 16th and 17th century were able to project images onto paper or glass but the study of capturing, processing and printing the images took many more years. Up until the 17th century, scientists believed that light was composed basically of the ‘white’ that is perceived by the human eye. It took the research done by famous physicist Isaac Newton to discover that light is actually composed of a spectrum of colors. While he made a big contribution to the study of optics (that is at the core of camera advances) with this discovery, Newton did not actually have anything to do with camera development per se.

The early camera that first became a phenomenon was a little more than a pinhole camera and can be traced back to 1558. It was called the Camera Obscura. The Camera Obscura was seen as a drawing tool for a clearer and realistic portrayal of objects. It was in the early 19th century that an invention named the Camera Lucida was introduced by Cambridge scientist William Hyde Wollaston that consisted of an optical device that could help an artist view a distant scene or person or object on a paper surface that he or she was using to draw. In other words the artist gets to view a superimposed image of a subject on paper and this image could be effectively used to attempt to draw, trace or paint it. Both the Camera Obscura and the Camera Lucida provided an image that was temporary, which could not be lastingly captured on to paper for later reference.

Studies however continued well into the 1800’s on how to actually capture the image onto material. It was during this time, around 1822 that French researcher Joseph Nicephore Niepce, created the first photograph by using paper that was coated with a chemical. The image would not stay permanently on the paper and would disappear after a short while. Even so, despite the short-lived nature of the image, the concept of photography was born with this experiment and paved the way for further study and development in this field.

Capturing images to retain them longer and permanently became the next big quest for researchers. Another Frenchman Louis-Jacques-Mandé Daguerre partnered with Joseph Nicéphore Niépce in 1829, to develop the process of creating permanent photographs. Joseph Niépce died in 1833 but Daguerre continued with the work and succeeded in 1837 after many long years of experimentation. The process of capturing photographic images that would not fade away, introduced by Daguerre came to be known as the ‘daguerreotype’.

The word ‘photography’ was coined by scientist Sir John F.W. Herschel in 1839 and it is actually is derived from two Greek words ‘photos’ meaning light and ‘graphein’ meaning draw.

A slightly more advanced version of the daguerreotype called the Calotype process that makes multiple copies possible using the negative and positive method became available very soon after. In fact, it was during the 1840’s that the use of photographic images in advertisements first started and cameras made their mark on the power of visual communication. It was not much later, in the 1850’s that photographers first started experimenting with underwater photography of seascapes.

Up until 1850, the process of capturing images was cumbersome requiring upto half an hour of light exposure. The discovery made in 1851 by Frederick Scott Archer was a blessing since the new method termed the Collodion process called for just 2-3 seconds of light exposure to capture an image.

Prior to 1871, photographers went through a development process where they had to coat the plate with wet chemical each and every time and process the image immediately. With the invention the gelatin dry plate silver bromide process by Richard Leach Maddox, negatives did not have to be developed immediately.

This was an important discovery since up until then the captured image had to be processed instantly.

Kodak created in 1888 by George Eastman has been a modern day pioneer of sorts in cameras and photography for the masses. George Eastman and the scientists who worked with him at Kodak developed the photographic film in 1889 and made it available in rolls for the mass use of consumers. An important milestone in our entertainment and communication history was the development of transparent roll film by Eastman. This development led to another key invention – the motion picture camera by Thomas Edison’s in 1891.

-->Modern Times

During the 20th century the pace of technology development in cameras and photography continued at an accelerated pace much like many other key technology developments. While several key inventions like car, telephone and the gramophone record happened in the later half of the 19th century, it is the last 100

years that saw major developmental work in many areas of communications technology and as well as in other fields – TV, aircrafts, PCs, digital technology, digital cameras, mobile phones, fax machines and the internet, to name a few.

In the case of the camera, the developments simplified the whole process of photography, making it accessible to one and all at affordable prices and the camera industry denizens of our times made it into a mass phenomenon. The first mass use camera became available at the turn of the 20th century and can be

traced back to the year 1900. There are hundreds of models of cameras available today both for the amateur as well as the professional and the camera is an important part of any family’s repertoire of must have gadgets.

-->20th century chronology in the history of the camera:

1913: 35 mm still-camera created

1927: The flash bulb introduced by General Electric Co. (The concept of camera flash existed much before but was based on the use of a flash light powder that was invented by German researchers)

1935- 1941: Kodak starts marketing Kodachrome film and subsequently launches Kodacolor negative film. Canon released the Hansa Canon in 1936, the first 35mm focal-plane shutter camera.

1948: The concept of the Polaroid camera is introduced in the market. American scientist Edwin Land developed the process for instant photography. Later Polaroid Corporation developed the ‘instant color’ film around 1963.

1957: Frenchman Jaques Yves Cousteau invented the first waterproof 35mm camera for underwater photography named the Calypso Phot. The actual camera was developed by the Belgian airplane technical designer Jean de Wouters based on the blueprint and suggestions given to him by Cousteau.

1972: The electronic camera that does not require film was created and patented by Texas Instruments. This is however not the same as a digital camera though you don’t require film in digital cameras as well. The launch of the digital camera is still many years away.

1975: Kodak’s experiments with digital imaging kicked off around the mid seventies but it will take another 20 years before a digital camera for the home consumer market is launched.

1978 – 1980: Asian players like Konica and Sony begin to make their mark. The ‘point and shoot’ automatic focus camera is launched by Konica while Sony starts talking about the camcorder and demonstrates a prototype.

1981: Sony launches a commercially available electronic still camera. Similar to the 1972 invention by Texas Instruments, the Sony electronic camera came with a mini disc on which images were recorded and stored. The recorded images could be later printed or viewed on a monitor using a reader device.

1985: Digital processing technology makes its entry. Digital imaging and processing is introduced by Pixar.

1986: The camera industry becomes even more consumer focused and taps the fun and travel connotations behind camera usage, with the launch of the concept of the disposable single use cameras. Fuji is credited with the development of this concept.

Also in 1986 - 1987, Kodak started taking giant strides in digital development. Digital means, the photographic image is divided into tiny units of dots or squares known as pixels. Pixels are the programmable units of an image that can be processed by computers. Each image could be made up of millions of pixels.

The use of pixels in digital technology allows storing large volumes of pixels to deliver high definition print quality.

1990: Kodak introduces Photo CD’s. It is a system of storing photographic images on CD and then viewing them on a computer. With this development the user-friendly approach of the camera industry began to take concrete shape.

1991: Kodak introduces a digital camera targeted at professionals and journalists. Kodak is credited with the invention of a pixel based camera technology known to us as the digital camera. Digital cameras don’t use film similar to their predecessor electronic cameras but the storage method is entirely

different and the final photograph is of much higher resolution. In a digital camera photos are recorded and stored in digital form. This digital data can be transferred to a computer and processed for printing. Kodak and Canon are well known digital camera manufacturers and there are also several other key brands as well.

1994: The Apple QuickTake camera, a home use digital camera is launched. This is followed by the launch of a clutch of home use digital cameras by Casio, Kodak and others in quick succession during 1995 -’96.

-->The digital era:

The development of digital camera technology is considered to be linked to the development of TV and Video technology. The principles of transmission and recording of audio-visual images using digital electrical impulses finds use in camera imaging as well.

Through the 1990’s the developments continued in camera technology, the focus now shifting to the field of digital imaging which is where the future lies.

Use- friendly features like software that can download digital images directly from camera onto home computers for storing and sharing on the internet is the new norm in the market place.

The camera, the computer, the software industry and the worldwide web are today irrevocably interlinked to empower the user in experiencing the benefits of camera usage to full potential. The innovation that sparked many an invention in the camera industry found its way into the digital world as well and continued among digital camera manufacturers. During 2001, the Kodak and Microsoft partnership ensured that digital camera manufacturers could use the power of Picture Transfer Protocol (PTP) standard through Windows. The digital photo experience is a key visual driver in the Internet era. Many of Kodak digital camera models with EasyShare capabilities are compatible with Windows XP. The Kodak EasyShare software enables users to transfer digital camera pictures directly from camera to their computers and then print the pictures or even email them.

Manufacturers in a related industry like the printing industry have adapted their products to be in sync with the images created by digital cameras. Cell phone manufacturers have tied up with digital camera manufacturers to develop new age camera phones in recent years. These camera phones can capture images and share the images through the cell phone.

Among the 21st century digital developments are the advanced product offerings from digital cameras manufacturers and these are sure to occupy an important place in the ensuing history of camera development. For instance, the Kodak Professional DCS Pro SLR/c is a high-end digital camera and the Kodak website calls the DCS Pro SLR models the most feature-rich digital cameras on the market. It has an image sensor that can handle 13.89 million pixels and this makes it the highest resolution digital camera available. High resolution determines the sharpness or level of detail in photographic images. This is just a glimpse of the capabilities that digital technology places in a user’s hands. Digital camera sales figures for 2003 show that the two key players Kodak and Canon have recorded impressive growth.

-->What does the future holds for camera users?

The features offered by digital cameras can be quite mind-boggling for the average user and pretty exciting for most pros. Four key ongoing camera

developments that are likely to further improve the process of photography:

Greater resolution from even the simplest, low cost camera models
Usage in any type of lighting conditions,
Compatibility across a range of software, hardware and image types
Rich colors and tone
While the higher-end digital evolution continues, the prices of the simple camera have crashed to such an extent that even children and teens are proud owners of uncomplicated cameras. The camera and photography interest starts young and this creates a truly large audience base for the camera industry.

And throughout history, it is evident that the endeavor of researchers and developers has been to make the camera available to a wide section of society.

Without camera technology and photography, the other key developments of cinema and TV would have been delayed and what a boring place the world would have been without TV and films!!

Taken from :
Chris Haslego
http://www.cameramanualstore.com

History of Computing

2008-04-08T23:10:00.000-07:00

History of computing

It is difficult to identify any one device as the earliest computer, partly because the term "computer" has been subject to varying interpretations over time. Originally, the term "computer" referred to a person who performed numerical calculations (a human computer), often with the aid of a mechanical calculating device.

The history of the modern computer begins with two separate technologies - that of automated calculation and that of programmability.

Examples of early mechanical calculating devices included the abacus, the slide rule and arguably the astrolabe and the Antikythera mechanism (which dates from about 150-100 BC). The end of the Middle Ages saw a re-invigoration of European mathematics and engineering, and Wilhelm Schickard's 1623 device was the first of a number of mechanical calculators constructed by European engineers. However, none of those devices fit the modern definition of a computer because they could not be programmed.

Hero of Alexandria (c. 10 – 70 AD) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions - and when.^[3] This is the essence of programmability. In 1801, Joseph Marie Jacquard made an improvement to the textile loom that used a series of punched paper cards as a template to allow his loom to weave intricate patterns automatically. The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early, albeit limited, form of programmability.

It was the fusion of automatic calculation with programmability that produced the first recognisable computers. In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer that he called "The Analytical Engine".^[4] Due to limited finances, and an inability to resist tinkering with the design, Babbage never actually built his Analytical Engine.

Large-scale automated data processing of punched cards was performed for the U.S. Census in 1890 by tabulating machines designed by Herman Hollerith and manufactured by the Computing Tabulating Recording Corporation, which later became IBM. By the end of the 19th century a number of technologies that would later prove useful in the realization of practical computers had begun to appear: the punched card, Boolean algebra, the vacuum tube (thermionic valve) and the teleprinter.

During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers.

*Defining characteristics of five early digital computers*
Computer	First operation	Place	Decimal/Binary	Electronic	Programmable	Turing complete
Zuse Z3	May 1941	Germany	binary	No	By punched film stock	Yes (1998)
Atanasoff–Berry Computer	Summer 1941	USA	binary	Yes	No	No
Colossus	December 1943 / January 1944	UK	binary	Yes	Partially, by rewiring	No
Harvard Mark I – IBM ASCC	1944	USA	decimal	No	By punched paper tape	Yes (1998)
ENIAC	1944	USA	decimal	Yes	Partially, by rewiring	Yes
ENIAC	1948	USA	decimal	Yes	By Function Table ROM	Yes

A succession of steadily more powerful and flexible computing devices were constructed in the 1930s and 1940s, gradually adding the key features that are seen in modern computers. The use of digital electronics (largely invented by Claude Shannon in 1937) and more flexible programmability were vitally important steps, but defining one point along this road as "the first digital electronic computer" is difficult (Shannon 1940). Notable achievements include:

Konrad Zuse's electromechanical "Z machines". The Z3 (1941) was the first working machine featuring binary arithmetic, including floating point arithmetic and a measure of programmability. In 1998 the Z3 was proved to be Turing complete, therefore being the world's first operational computer.
The non-programmable Atanasoff–Berry Computer (1941) which used vacuum tube based computation, binary numbers, and regenerative capacitor memory.
The secret British Colossus computer (1944), which had limited programmability but demonstrated that a device using thousands of tubes could be reasonably reliable and electronically reprogrammable. It was used for breaking German wartime codes.
The Harvard Mark I (1944), a large-scale electromechanical computer with limited programmability.
The U.S. Army's Ballistics Research Laboratory ENIAC (1946), which used decimal arithmetic and is sometimes called the first general purpose electronic computer (since Konrad Zuse's Z3 of 1941 used electromagnets instead of electronics). Initially, however, ENIAC had an inflexible architecture which essentially required rewiring to change its programming.

Several developers of ENIAC, recognizing its flaws, came up with a far more flexible and elegant design, which came to be known as the stored program architecture or von Neumann architecture. This design was first formally described by John von Neumann in the paper "First Draft of a Report on the EDVAC", published in 1945. A number of projects to develop computers based on the stored program architecture commenced around this time, the first of these being completed in Great Britain. The first to be demonstrated working was the Manchester Small-Scale Experimental Machine (SSEM) or "Baby". However, the EDSAC, completed a year after SSEM, was perhaps the first practical implementation of the stored program design. Shortly thereafter, the machine originally described by von Neumann's paper—EDVAC—was completed but did not see full-time use for an additional two years.

Nearly all modern computers implement some form of the stored program architecture, making it the single trait by which the word "computer" is now defined. By this standard, many earlier devices would no longer be called computers by today's definition, but are usually referred to as such in their historical context. While the technologies used in computers have changed dramatically since the first electronic, general-purpose computers of the 1940s, most still use the von Neumann architecture. The design made the universal computer a practical reality.

Vacuum tube-based computers were in use throughout the 1950s. Vacuum tubes were largely replaced in the 1960s by transistor-based computers. When compared with tubes, transistors are smaller, faster, cheaper, use less power, and are more reliable. In the 1970s, integrated circuit technology and the subsequent creation of microprocessors, such as the Intel 4004, caused another generation of decreased size and cost, and another generation of increased speed and reliability. By the 1980s, computers became sufficiently small and cheap to replace simple mechanical controls in domestic appliances such as washing machines. The 1980s also witnessed home computers and the now ubiquitous personal computer. With the evolution of the Internet, personal computers are becoming as common as the television and the telephone in the household.

From Wikipedia, the free encyclopedia

What is computer?

2008-04-08T23:02:00.000-07:00

A computer is a machine that manipulates data according to a list of instructions.

The first devices that resemble modern computers date to the mid-20th century (around 1940 - 1945), although the computer concept and various machines similar to computers existed earlier. Early electronic computers were the size of a large room, consuming as much power as several hundred modern personal computers.^[1] Modern computers are based on tiny integrated circuits and are millions to billions of times more capable while occupying a fraction of the space.^[2] Today, simple computers may be made small enough to fit into a wristwatch and be powered from a watch battery. Personal computers in various forms are icons of the Information Age and are what most people think of as "a computer"; however, the most common form of computer in use today is the embedded computer. Embedded computers are small, simple devices that are used to control other devices — for example, they may be found in machines ranging from fighter aircraft to industrial robots, digital cameras, and children's toys.

The ability to store and execute lists of instructions called programs makes computers extremely versatile and distinguishes them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore, computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks given enough time and storage capacity.