What-Is-What.com Recent Questions

What is a URL?

Fri, 23 Nov 2007 18:40:21 EST

URL is an acronym for Uniform Resource Locator. URL is the technical term for what is often called a "web address". It is the address by which computers and documents on the Internet can be located. The URL was invented by Tim Berners-Lee as one of his many contributions to the World Wide Web. The URL is a short text string that contains the name of a computer on the Internet, a protocol for communicating with that computer, a path and filename of a document on that computer, and sometimes additional information as well. The inclusion of all this information in a single string is allows for seamless interaction between computers on the Internet and rapid exchange of information. The URL was designed to be extensible in the sense that as new types of documents are added to the Internet, the URL would be able to adapt and uniquely identify each document with regard to each new document format's needs. A full URL consists of a service name, followed by a colon and a hostname, optionally followed by a colon and a port number, followed by a path which ends in a filename or directory. An example of a full URL looks like this: "service:hostname.com:80/directory/file.html". Most URLs that are handled by humans are the addresses of documents on the World Wide Web. These URLs usually specify the HTTP protocol and have the port number eliminated. Additionally, the hostname of a WWW address begins with two forward slashes. An example of such a URL looks like this: "http://hostname.com/". Note that in this example the path specified is a single forward slash, and no file name was specified. This tells the webserver that you are requesting the default file in the topmost public directory of the server. If the webserver has no default file configured then it may return either a list of the files in the directory or an error. A common user error is to specify a URL with no path. Although most webservers are configured to handle this error by automatically assuming that the user wants the default document in the topmost directory, this causes unnecessary server load and may lead to the wrong document being served. Although a URL specifies a specific document's location on the Internet, electronic documents can be easily copied and therefore may have more than one location. Hence, the concepts of URN (Uniform Resource Name) and URI (Uniform Resource Identifier) have been developed. URNs specify the name of a particular resource, regardless of it's location. URIs are simply complete URLs in which the filename is a URN. For example, two webservers may both have a copy of the book 1984. The book may have any filename, but the International Standard Book Number for 1984 will always be "ISBN 0-452-28423-6". Therefore, the URN of the book 1984 would logically be "isbn.0-452-28423-6". A URL of the type "http://server1.com/isbn.0-452-28423-6" would therefore be a URI for the book 1984. Another URI for the same book could possibly be "http://server2.net/books/isbn.0-452-28423-6". Both URIs would ideally point to identical documents. The difference between a URL and a URI is often arbitrary, as most documents on the World Wide Web are not named by any standards organization.

What is Storm?

Sun, 09 Dec 2007 01:42:53 EST

The Storm Botnet is a distributed computer network consisting of computers remotely controlled without their owner's knowledge. Computers in the Storm Botnet are home and small office machines running the Microsoft Windows operating system which have been infected by the Storm worm. Storm got it's name as the worm was first spread though spam email with the subject "230 dead as storm batters Europe." Today, the Storm Botnet is considered to be the largest botnet in the world, with as many as 5 million computers under it's control. Efforts to combat Storm have been met with targeted resistance, suggesting that artificial intelligence and automated adaptive defense techniques are being utilized. The Storm worm, termed Nuwar by Microsoft but popularly referred to as Storm, was first identified in January 2007. Within one week of it's discovery, the worm had successfully infected over one million personal computers. This success is credited to the ambiguous yet catchy email subject lines in propagation emails, which like the original "storm" subject often referred to current news events. When these email messages are opened in an insecure email client such as Outlook or Outlook Express, an executable attachment downloads and installs several malware packages to the host computer. Usually, in addition to a trojan and a worm update, a rootkit is installed on the host computer, thereby masking any evidence of infection. In fact, the Storm rootkit had been proven to disable any anti-virus programs running on the computer while leaving it's executable file running. The updated worm then mutates slightly, harvests email addresses in the email client and browser cache, and sends itself to those addresses. Unlike other worms which have a master computer hard-coded into their code, the mutated Storm worm contains only a list of other Storm-infected machines with which it can communicate, but not the address of the botnet master. Communication between each Storm node and the master is performed in a P2P fashion, with each machine functioning as both a slave and as a messenger between nodes. Once a computer is infected with the Storm worm, it becomes part of the Storm Botnet. With 250,000 nodes active at any particular time, the Storm Botnet is estimated to range between 2 million and 5 million computers total. This provides the network with more RAM, disk space, and computing power than many of the world's most powerful supercomputers. However, Storm's strength is not in it's shear computing resources but rather in it's distributed nature, as the computers consisting of the botnet have more available bandwidth than most countries have in their entirety. DDoS attacks originating from even a tenth of the Storm Botnet could shut down many governments and international organizations such as the United Nations and the Red Cross which today depend upon the Internet for vital communications. However, as of late 2007 the only DDoS attacks attributed to Storm are those targeted at IP addresses that have been used to probe Storm nodes in malware research.

What is a Hybrid Vehicle?

Fri, 02 Nov 2007 15:11:39 EDT

A hybrid car is an automobile that has two or more major sources of propulsion power. Most hybrid cars currently marketed to consumers have both conventional gasoline and electric motors, with the ability to power the vehicle by either one independently or in tandem. These vehicles are appropriately termed gas-electric hybrids. Other power sources may include hydrogen, propane, CNG, and solar energy. The technology used depends on the goals set for the vehicle, whether they be fuel efficiency, power, driving range, or reduced greenhouse gas emissions. Consumer oriented hybrid cars, which have been on the market for about ten years, are usually tuned for reduced emissions and driving range. Corporate and government fleets that have been in service for twenty years or more are usually tuned for fuel efficiency, often at the cost of driving range, power, and hydrocarbon emissions. A gasoline-electric hybrid car has one or two auxiliary electric motors that supplement the main gasoline engine. Compared to conventional automobiles, the gasoline engine in a gas-electric hybrid is smaller, less powerful, and more efficient. Although the gasoline engine alone would be sufficient to power the vehicle under most circumstances, during maneuvers requiring unusually high power the electric motor is used as well. These conditions include passing, hill climbing, and acceleration from a standstill. Some hybrid cars, such as the Toyota Prius, shut down the gasoline engine under conditions in which the electric motor alone would suffice, such as coasting and breaking. In fact, the Toyota Prius has a special electric-only mode designed for stop-and-go traffic. This is made possible by the super heavy duty electric motor used in the Prius, which is capable of propelling the vehicle from a standstill without the gasoline assist. Thus, in contrast to most other hybrid vehicles, the Prius actually uses the electric motor more than the gasoline engine. Many of the technologies found in hybrid vehicles would benefit vehicles of any type, including conventional gasoline automobiles. However, the engineering and manufacturing costs associated with these technologies often would increase the price of the vehicle to the point where the fuel savings are negligible in comparison. Only in tax-subsidized electric and hybrid vehicles are these technologies practical, in which associated cost increases are absorbed by the government instead of the manufacturer or consumer. These technologies include regenerative braking, aerodynamic refinements, and lightweight building materials.

What is Teleportation?

Thu, 25 Oct 2007 19:14:46 EDT

Teleportation is the transfer of physical objects from one place to another, distant place, without transferring the physical particles that constitute the original object. By most definitions, the object in its original location is either destroyed or rendered otherwise unrecognizable and unable to function. This limits teleportation devices to transportation roles only, incapable of duplicating or manufacturing objects. Although teleportation devices were until recently considered by the scientific community to stay confined to the realm of science fiction, recent understandings of quantum mechanics have led to the development of successful teleportation techniques. The current state of the art in teleportation technology, having successfully moved relatively large masses relatively large distances, relies on the uncertainty principle and quantum entanglement phenomenon. The uncertainty principle states that the more information that is extracted from an object, the more the object is malformed. The point in which the object is so malformed as to prevent further scanning occurs well before enough information is extracted to produce an exact copy. Quantum entanglement allows the quantum state of one particle to be predicted based upon the quantum state of another particle that had once been in contact with it. Thus, a teleportation sending station and receiving station can be prepared by bringing two such particles into contact, and then bringing one to the sending station, and the other to the receiving station. The particle at the sending station is then scanned along with the object to be teleported. The scanning process malforms both the particle and the object. The scanned information is then sent to the receiving station, which then performs the reverse process to raw material together with the second particle. As the second particle is currently in the same quantum state as the first particle, together with the original object, the finished product is identical to the original object. The first objects to be successfully teleported were photons, or light particles. These massless particles are ideal for such experimentation as the have relatively few quantum states and readily entangle with other photons. As early as 1998 experiments have proven with over 75% accuracy that the quantum state of a photon can be imparted on a distant photon by way of an intermediate photon that is quantumly entangled with the target photon. While this method could theoretically be used to transmit data, it would not permit the movement of tangible objects. Six years later, two separate research teams had independently succeeded in teleporting collections of atoms. Although the atoms themselves had been teleported, their respective arrangement had not been preserved. Thus, the current state of the art does not permit the teleportation of large or complex structures. However, new developments in technology, as well as a more thorough understanding of quantum mechanics, may help researchers overcome that obstacle.

What is a Decibel?

Sat, 20 Oct 2007 10:16:14 EDT

The decibel is the common measure of sound intensity and radio signal strength. Although it has never been ratified by any governing standards body, its suitability to measuring ratios and losses has led to widespread adoption of the decibel in industry and research. Although most commonly used today as a measure of sound intensity in air, the decibel was actually invented to measure the loss of sound intensity in electrical wire. In its regular form, the decibel is abbreviated "dB". When used to measure ratios of other forms of energy intensity the abbreviation is postfixed with appropriate, though non-standard, abbreviation. For instance, "dBk" indicates kilowatt loss, and "dBv" indicates voltage loss. Sound is perceived by humans and most animals in a logarithmic manner of intensity. Therefore, the bel system of sound intensity measurement is also logarithmic. Zero on the bel scale is the human hearing threshold, perceivable only by the young, and 1 is the level that any healthy human can perceive. Each increase of 1 point on the bel scale corresponds to a tenfold increase in noise intensity, although due to the logarithmic nature of human hearing, is perceived only as a threefold increase. As the bel system measurements are too large for practical use, the decibel system is more commonly used. As the name implies, an increase of ten decibels is equivalent to an increase of one bel. However, a decibel is not considered one tenth of a bel, as the scale is logarithmic. A convenient consequence of the logarithmic scale is that a change of 1 decibel at normal room levels (40-50 decibels) is the just noticeable difference for most people. As sound waves expand isotropically through air in a three-dimensional manner, their intensity reduces as an inverse function of the square of the distance from the sound source. This translates to a 6 decibel decrease for every doubling of distance. Studies have led to the establishment of safe sound levels for long term human exposure that, when followed, significantly reduce the danger of hearing loss. The United States Environmental Protection Agency has established 70 decibels as the maximum safe daily average. In practice, this is only slightly higher than the natural sound levels in most office buildings, and is significantly lower than the ambient sound levels in almost all industrial work environments. For instance, the manufacturing, construction, and transportation industries all expose their workers to 90 decibels on a regular basis, with the ambient sound level rarely going below 65 decibels. Improved equipment designed specifically for reduced sound levels and mandatory use of hearing protection help prevent sound-related injuries.

What is Noise Pollution?

Sun, 09 Dec 2007 01:47:03 EST

Noise pollution is a type of energy pollution in which distracting, irritating, or damaging sounds are freely audible. As with other forms of energy pollution (such as heat and light pollution), noise pollution contaminants are not physical particles, but rather waves that interfere with naturally-occurring waves of a similar type in the same environment. Thus, the definition of noise pollution is open to debate, and there is no clear border as to which sounds may constitute noise pollution. In the most narrow sense, sounds are considered noise pollution if they adversely affect wildlife, human activity, or are capable of damaging physical structures on a regular, repeating basis. In the broadest sense of the term, a sound may be considered noise pollution if it disturbs any natural process or causes human harm, even if the sound does not occur on a regular basis. The prevailing source of artificial noise pollution is from transportation. In rural areas, train and airplane noise can disturb wildlife habits, thereby affecting the manner in which animals in areas around train tracks and airports hunt and mate. In urban areas, automobile, motorcycle, and even entertainment noise can cause sleep disruption in humans and animals, hearing loss, heart disease (as a result of stress), and in severe cases even mental instability. A notable exception to the rule is the electric, or hybrid-electric, automobile. Hybrid vehicles are so quite, in fact, that legislation is pending to actually make them louder. This is in response to numerous injuries in which pedestrians, unaware of a hybrid vehicle's presence, have been struck by such vehicles in parking lots and pedestrian crosswalks. Although most developed nations have government agencies responsible for the protection of the environment, no nation has a single body that regulates noise pollution. In the United States, regulation of noise pollution was stripped from the federal Environmental Protection Agency and passed on the the individual states in the early 1980's. Although two noise-control bills passed by the EPA are still in effect, the agency can no longer form relevant legislation. In the United States, Canada, Europe, and most other developed parts of the world, different types of noise are managed by agencies responsible for the source of the noise. Transportation noise is usually regulated by the relevant transportation ministry, health-related work noise is often regulated by health ministries and worker's unions, and entertainment noise such as loud music is a criminal offense in many areas. As the bodies responsible for noise pollution reduction usually view noise as an annoyance rather than a problem, and reducing that noise often hurts the industry financially, little is currently being done to reduce noise pollution in developed countries.

What is the Kyoto Protocol?

Sun, 09 Dec 2007 01:27:27 EST

The Kyoto Protocol is the first legally binding update to United Nations Framework Convention on Climate Change. The UNFCCC was developed at the 1992 Earth Day summit in Rio de Janeiro with the intention of balancing worldwide greenhouse gas emissions at a sustainable level. As a non-binding agreement, UNFCCC included provisions for mandatory updates that are legally binding in and of themselves. As the first UNFCCC update, the Kyoto Protocol has been hotly debated in all major UNFCCC signatory states. Some of the major UNFCCC signatories, notably Australia and the United States, have yet to ratify the Kyoto Protocol on economic or fundamental basis. The Kyoto Protocol identifies six greenhouse gases, or gaseous emissions typical of technologically-advanced societies that are suspected of catalyzing global climate change. Each signatory country is allocated GHG emission allowances, which can be sold or traded in a barter market. Industrialized nations that sign the Kyoto Protocol pledge to either reduce their GHG emissions to certain acceptable levels, or to buy GHG emissions allowances from developing nations that emit less than their allowance. This approach has a twofold benefit. On one side, the industrialized nations are able to continue emitting GHGs while they develop less toxic technology, and are monetarily penalized until they find solutions. On the other side, developing nations are financially encouraged to keep their emissions low, and they are free to use that money to develop environmentally-friendly power infrastructures. The Kyoto Protocol has been met with much opposition by industrialists, economists, and other groups that tend to favor the rich. They argue that the Kyoto Protocol was devised to balance the spread of wealth among nations. This would have rich, industrialized nations paying developing nations for an artificial resource, GHG emissions allowances. Thus, they argue, the industrialized nations are essentially profiting from the Kyoto Protocol without contributing anything, while industrialized nations are essentially paying without receiving anything in return. On these grounds nations such as the United States and Australia have not signed the treaty, even though Australia is within 1% of meeting it's greenhouse gas emissions allowance even without allocating additional resources to the effort.

What is Yamaha Corporation?

Tue, 02 Oct 2007 16:38:08 EDT

Yamaha Corporation is a diverse Japanese technology company. Yamaha currently produces musical instruments, consumer electronics, heavy industrial equipment, microprocessors, and motor vehicles. The company is recognized as a leader in fields as diversified as audio research and development, to small engine and motorcycle design, to robotics. Yamaha currently has official distribution channels in almost every country in the world, and operates laboratories and research facilities on almost every continent. Torakusu Yamaha first began selling reed organs in 1887, and incorporated his company ten years later as The Nippon Gakki Co, Ltd. Within five years of incorporation the company diversified into furniture making, as the wood finishing expertise learning in organ and piano making was well suited to fine furniture. This diversification would become a hallmark of the company, as Yamaha would diversify and expand it's operations at almost every opportunity. By the second world war, Yamaha was a world leader in acoustics research, and was manufacturing phonographic equipment in addition to furniture and musical instruments. In 1955 the company introduced Yamaha Motor Corporation, selling a re-engineered German motorcycle of WWII design. Today, the Yamaha logo consists of three tuning forks against the silhouette of a cymbal, homage to the company's roots as a musical instrument manufacturer. Yamaha owes it's success to it's management's continuous willingness to take business risks and diversify. In the 1930s, Yamaha pioneered acoustics research and helped develop some of the world's leading concert halls of the time. Yamaha introduced the world's first 3-wheeled ATV, was the first company to fit single shock absorption systems to production motocross bikes, and the first company to market a 5-valve cylinder head. Recent Yamaha motorcycle innovations include electronically-controlled variable intake stacks, quick-release touring windshield and passenger backrest with touring bags, and even a small airbag system. Recent Yamaha musical innovations include singing synthesis software, concert-quality carbon-bodied bows, and electric "silent" string instruments such as violins, bass, and cellos. Ground-breaking and risky technologies are marketed in all Yamaha products, from high-sales motorcycle markets to specialty niche markets such as electric violins.

What is FUD?

Sun, 09 Dec 2007 01:39:59 EST

FUD is an acronym for "fear, uncertainty, and doubt." FUD is often employed as a semi-legitimate marketing tool in the technology sector, in which purchasing decisions are often made by parties who are unable to completely assess two competing products. As FUD is usually based upon the lack of information, rather than the availability of information, FUD campaigns are very effective in influencing decision-makers who do not fully understand a given technology. It is the FUD campaigner's goal to prevent assessment of knowledge, which is a far easier goal than promoting knowledge and teaching prospective clients about new technologies. Although fear-based persuasion is frowned upon in most fields of business, and even illegal in some cases, the technology sector has a history the practice. This is attributed to the traditionally closed-source and specialized nature of hardware and software, which creates a situation in which consumers do not have access to, or are unable to comprehend, all aspects of a product. Although traditional FUD campaigns center on interoperability, reliability, and maintenance issues, recent campaigns have raised the issue of consumer liability. Claims that competing products may violate intellectual property or copyright restrictions are becoming commonplace. Notable among these is Microsoft's recent claim that the Linux kernel violates over one hundred Microsoft patents. Microsoft is very careful not to specify which patents are being infringed upon, or what parts of the freely-available Linux source code are infringing, thus providing no evidence of infringement. The uncertainty thus raised prevents lawsuit-cautious corporations from using Linux, without any technical merit. In fact, the solution provided by Microsoft is often technically inferior to competing products, as is the case with the Windows operating system and, arguably, the Microsoft Office suite. A similar campaign had been waged by SCO against IBM's competing products. Although successful in hindering adoption of IBM's AIX operating system, SCO's vague claims of intellectual property infringements were thrown out of the court hearing the matter. The term FUD was originally used by a former IBM employee against IBM itself. Gene Amdahl, founder of Amdahl Corporation, had accused IBM of spreading "fear, uncertainty, and doubt" regarding interoperability between his IBM-compatible hardware and official IBM software. He claimed that IBM was playing on customers emotions, not proper reasoning, to make business decisions. Although in many markets IBM's FUD tactics were successful, Amdahl succeeded in winning over 20% market share in several key geographical markets. Notably, the prominent display of Amdahl accessories such as keychains and coffee mugs during conference with IBM marketers had become fashionable among the technically elite. This was perceived not only as a display of knowledge of competitor's products, but also as a display of values and proper decision-making ability.

What is Electricity?

Mon, 07 Jan 2008 11:29:04 EST

Electricity is a broad term encompassing the family of phenomenon arising from interaction between charged particles. Of the four fundamental forces of nature, the electromagnetic force is the most influential in our everyday lives. It is responsible for holding materials together, interaction between objects, and even light. Although the existence of electrical phenomenon have been known since ancient times, the properties of electricity have been known to science for less than three hundred years. Even so, almost all modern inventions utilize electricity in some way. Electrically-charged particles fall under two categories, positive and negative. All positively-charged particles repel all other positively-charged particles, yet attract negatively-charged particles. Likewise, all negatively-charged particles repel each other while attracting positively-charged particles. Thus, no three electrically-charged particles can simultaneously attract one another. The strength of attraction (or repulsion) is inversely proportional the the square of the distance between the particles. Therefore, objects that consist of an equal amount of positively- and negatively-charged particles display an overall net electric charge of zero at distances much greater than the distance between the charged particles themselves. In everyday life, the positively charged particles that we encounter are the protons in the nucleus of the atom, and the negatively charged particles that we encounter are the electrons surrounding the nucleus. As even the smallest distances that humans can perceive are orders of magnitude above the atomic radius, we do not usually perceive electrical interactions directly. However, the movement of electrons as electric current is very influential in modern life, and is very apparent to unaided observation. Similarly, magnetic and chemical interactions are easily observed, and both of these phenomenon are based upon the interaction between electrically-charged atomic particles. The first suspected human application of electricity is the ancient Egyptian Dendera Light, dating to about 300 BC. The Baghdad Battery, dating between 250 BC and 640 AD, may be another ancient electrical device. The ancient Greeks were the first to record knowledge of electrical phenomenon in their writings. They observed both lightning and static electricity, however they did not make any logical connections between the two. Chinese scientists wrote about the use of magnetite as an alternative to celestial navigation. However, it was not until the 17th century that scientists began actively investigating electricity. Otto von Guericke developed the first electrostatic generator in 1660, and Pieter van Musschenbroek invented the electrical capacitor in 1745. These two inventions provided scientists with on-demand electrical current, thus facilitating controlled experimentation. The work of Nikola Tesla and Thomas Edison brought electrical devices to everyday use.