A watch is a timepiece that is to be worn on a person, as opposed to a clock which is not. The term now usually refers to a wristwatch, which is worn on the wrist with a strap, while a pocketwatch, the common type before World War I, is carried in a pocket and often has an attached chain to lift it out. Watches evolved in the 1600s from spring powered clocks, which appeared in the 1400s. In addition to the time, modern watches often display the day, date, month and year, and electronic watches may have many other functions
Overview
The most common type of watch is the wristwatch, worn on the wrist and fastened with a watchband made of leather, nylon or other plastics (then called strap), metal links (called bracelet) or even ceramic. Before the inexpensive miniaturization that became possible in the 20th century, most watches were pocket watches, which had covers and were carried separately, often in a pocket and attached to a watch chain or watch fob.
In the 21st century, technological advances in metallurgy, composite materials development and physical vapor deposition greatly influence watch design and manufacturing. Solid stainless steel, titanium, tungsten carbide, carbon fiber, high-tech ceramic and ion plating processes dominate a considerable market share of today's modern watch-making industry. Sapphire crystals are often incorporated to complement and enhance the durability of a quality watch.
Most inexpensive and medium-priced watches used mainly for timekeeping are electronic watches with quartz movements. The most accurate watches have radio-controlled movements that are miniaturized, portable versions of radio clocks. Expensive, collectible watches valued more for their workmanship and aesthetic appeal than for simple timekeeping, often have purely mechanical movements and are powered by springs, even though mechanical movements are less accurate than more affordable quartz movements.
Watch cases
In the 15th century, navigation and mapping increased the desire for portability in timekeeping. The latitude could be measured by looking at the stars, but the only way a ship could measure its longitude was by comparing the midday (high noon) time of the local longitude to that of a European meridian (usually Paris or Greenwich)—a time kept on a shipboard clock. However, the process was notoriously unreliable until the introduction of John Harrison's marine chronometer. For that reason, most maps from the 15th century through the 19th century have precise latitudes but distorted longitudes.
The first reasonably accurate mechanical clocks measured time with simple weighted pendulums, which are unworkable when irregular movement of the fulcrum occur whether at sea or in watches. The invention of a spring mechanism was crucial for portable clocks. In Tudor England, the development of "pocket-clockes" was enabled by the development of reliable springs and escapement mechanisms, which allowed clockmakers to compress a timekeeping device into a small, portable compartment.
In 1524, Peter Henlein created the first pocket watch. It is rumored that Henry VIII (the portrait of Henry VIII at this link shows the medallion thought to be the back of his watch) had a pocket clock which he kept on a chain around his neck. However, these watches only had an hour hand—a minute hand would have been useless because of the inaccuracy of the watch mechanism. Eventually, miniaturization of these spring-based designs allowed for accurate portable timepieces (marine chronometers) which worked well even at sea.
In 1850, Aaron Lufkin Dennison founded Waltham Watch Company, which was the pioneer of the industrial manufacturing of pocket watches with interchangeable parts, the American System of Watch Manufacturing.
Breguet developed the first self-winding watch known as the perpetual in 1780.
Parts
The first two are key mechanisms within any mechanical watch of classical design; the third is optional:
The escapement – a mechanism that controls and limits the unwinding of the watch, converting what would otherwise be a simple unwinding, into a controlled and periodic energy release. The escapement does this by interlocking with a gear in a simple manner that switches between a "driven" and a "free" state, with abrupt locking at each end of the cycle. The escapement also for the same reason produces the ticking noise characteristic of mechanical watches.
The balance wheel together with the balance spring(also known as Hairspring) – these form a simple harmonic oscillator, which controls the motion of the gear system of the watch in a manner analogous to the pendulum of a pendulum clock. This is possible because the moment of inertia of the balance wheel is fixed, and the wheel as a whole provides a regular motion of known period.
The tourbillon – a rotating frame for the escapement. It is intended to cancel out or reduce the effects of bias to the timekeeping of gravitational origin, which might result from the watch being kept in a particular position for much of the day. It is technically very challenging to create a high quality tourbillon, and those made by specialists and found in prestige watches are often very highly valued.
NB: The pin-lever (also called Rosskopf) movement, as per the name of its inventor: Georges Frederic Roskopf: This cheaper version of the fully levered movement had been manufactured in huge quanties by many Swiss Manufacturers as well as Timex, has been replaced by Quartz movements.
Watch movements
A movement in watchmaking is the mechanism that measures the passage of time and displays the current time (and possibly other information including date, month and day). Movements may be entirely mechanical, entirely electronic (potentially with no moving parts), or a blend of the two. Most watches intended mainly for timekeeping today have electronic movements, with mechanical hands on the face of the watch indicating the time.
Mechanical movements
Purely mechanical watches are still popular, although they are most commonly seen among medium priced watches such as Fortis, Mido and TAG Heuer, and expensive watches like Patek Phillipe, Omega, Vacheron Constantin, A. Lange & Söhne, Rolex, Ulysse Nardin and Audemars Piguet. Their superb craftsmanship accounts for much of the attraction of purely mechanical watches. Compared to electronic movements, mechanical watches are inaccurate, often with errors of seconds per day. They are frequently sensitive to position and temperature, they are costly to produce, they require regular maintenance and adjustment, and they are more prone to failure.
Generally speaking, inexpensive and moderately priced timepieces with electronic movements now provide most users with timekeeping more accurate than the most expensive Rolex or Patek Phillipe. The most expensive, diamond encrusted Rolex contains a similar movement as its less expensive C.O.S.C rated brethren and all modern models can keep time to within 1 second a day. However, in recent times there has been less emphasis on one's watch for time precision as many people now carry multiple devices that will tell them the time accurately such as mobile phones, PDAs and laptops, these finely crafted mechanical watches have remained popular as precision time pieces and in many cases more so because of their aesthetic value as jewellery.
Tuning-fork movements
Tuning fork watches (introduced by Bulova in 1960) use a tuning fork at a precise frequency (most often 360 hertz) to drive a mechanical watch. Since the fork is used in place of a typical balance wheel, these watches naturally hum instead of tick.
The inventor, Max Hetzel, was born in Basel, Switzerland, and joined the Bulova Watch Company of Bienne, Switzerland, in 1948. Hetzel was the first to use an electronic device, a transistor, in a wristwatch. Thus, he developed the first watch that could be qualified as electronic. However, fork movements are actually more "electrical", like an old electrical wall clock, than electronic. The sweep second hand moves fluidly like that of an old electrical wall clock.
Such watches were also sold by Swiss watch companies under license of Bulova. In 1974, after leaving Bulova, Hetzel developed a different tuning fork drive for Omega Watches. The watch featured a cal. 1220 micromotor, and a tuning fork frequency of 720 hertz.[5] This development was obsolete compared to the newer electronic quartz watch which had become cheaper to produce and even more accurate.
Tuning fork movements are electromechanical. The task of converting electronically pulsed fork vibration into rotary movement is done via two tiny jeweled fingers, called pawls, one of which is connected to one of the tuning fork's tines. As the fork vibrates, the pawls precisely ratchet a tiny index wheel. This index wheel has over 300 barely visible teeth and spins more than 38 million times per year. The tiny electric coils that drive the tuning fork have 8000 turns of insulated copper wire with a diameter of 0.015 mm and a length of 90 meters. This amazing feat of engineering was prototyped in the 1950s.
Electronic movements
Electronic movements have few or no moving parts. Essentially, all modern electronic movements use the piezoelectric effect in a tiny quartz crystal to provide a stable time base for a mostly electronic movement: the crystal forms a quartz oscillator which resonates at a specific and highly stable frequency, and which can be used to accurately pace a timekeeping mechanism. For this reason, electronic watches are often called quartz watches. Most quartz movements are primarily electronic but are geared to drive mechanical hands on the face of the watch in order to provide a traditional analog display of the time, which is still preferred by most consumers.
The first prototypes of electronic quartz watches were made by the CEH research laboratory in Switzerland in 1962. The first quartz watch to enter production was the Seiko 35 SQ Astron, which appeared in 1969. Modern quartz movements are produced in very large quantities, and even the cheapest wristwatches typically have quartz movements.
The best quartz movements are significantly more accurate than the worst, but the difference is much smaller than that found between mechanical movements and quartz movements. Quartz movements, even in their most inexpensive forms, are an order of magnitude more accurate than purely mechanical movements. Whereas mechanical movements can typically be off by several seconds a day, an inexpensive quartz movement in a child's wristwatch may still be accurate to within 500 milliseconds per day—ten times better than a mechanical movement.
Quartz mechanisms usually have a resonant frequency of 32768 Hz, chosen for ease of use (being 215). Using a simple 15 stage divide-by-two circuit, this is turned into a 1 pulse per second signal responsible for the watch's keeping of time.
Recently, efforts have been made to combine the best features of quartz and mechanical movements. For example, the Seiko Spring Drive, introduced in 2005, uses a mainspring to power both a mechanical movement and, via a generator, a quartz regulator that controls its speed. The result is claimed to be a timepiece that operates as a mechanical watch, but with quartz accuracy.
Radio-controlled movements
Some electronic quartz watches are able to synchronize (time transfer) themselves with an external time source. These sources include radio time signals directly driven by atomic clocks, time signals from GPS navigation satellites, the German DCF77 signal in Europe, WWVB in the US, and others. These watches are free-running most of the time, but periodically align themselves with the chosen external time source automatically, typically once a day.
Because these watches are regulated by an external time source of extraordinarily high accuracy, they are never off by more than a small fraction of a second a day (depending on the quality of their quartz movements), as long as they can receive the external time signals that they expect. Additionally, their long-term accuracy is comparable to that of the external time signals they receive, which in most cases (such as GPS signals and special radio transmissions of time based on atomic clocks) is better than one second in three million years. For all practical purposes, then, radio-controlled wristwatches keep near perfect time.
Movements of this type synchronize not only the time of day but also the date, the leap-year status of the current year, and the current state of daylight saving time (on or off). They obtain all of this information from the external signals that they receive. Because of this continual automatic updating, they never require manual setting or resetting.
A disadvantage of radio-controlled movements is that they cannot synchronize if radio reception conditions are poor. Even in this case, however, they will simply run autonomously with the same accuracy as a normal quartz watch until they are next able to synchronize
Tuesday, January 29, 2008
watch
Monday, January 21, 2008
Retro iPod Alarm Clock
Now wake up and listen. We know you weren't in Take That. You know you weren't in Take That. So in the event that you wake up singing Back for Good you can either (a) bury your head under the pillow or (b) invest in the shockingly pink but really rather clever Retro iPod Alarm Clock.
It's a clock. It's a dock. It works superbly, irrespective of your taste in music. Synch it up to your iPod and, hey presto, it'll wake you up to your favourite tune from the Hit Parade, or your toppermost playlist, for that matter. And here's the even cleverer bit. As soon as you pop it in, it switches the iPod to clock mode and even starts charging it up while you're off in the land of nod.
And should the Sigue Sigue Sputnik emanating from the omni-directional speakers be a touch too loud for your delicate early-morning ear drums - and let's face it, there are times when even Roger Whittaker is too much for us - it even comes with that most retro of analogue features, a volume dial.
So, from hereon, on-time arrival at work is absolutely guaranteed. But whether it'll help you to sing in time is another matter entirely...
Features:
Wake up with your favourite music
charges iPod whilst docked
Suitable for most iPods except iPod Shuffle
AC adapter included
Not compatible with iPod Shuffle
Specification
Dimensions: Height: 14.0cm Width: 14.0cm Depth: 8.0cm
Weight: 0.5Kg
Saturday, January 19, 2008
Mobile phones tumour risk to young children
CHILDREN under the age of eight should not use mobile phones, parents were advised last night after an authoritative report linked heavy use to ear and brain tumours and concluded that the risks had been underestimated by most scientists.
Professor Sir William Stewart, chairman of the National Radiological Protection Board (NRPB), said that evidence of potentially harmful effects had become more persuasive over the past five years.
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The news prompted calls for phones to carry health warnings and panic in parts of the industry. One British manufacturer immediately suspended a model aimed at four to eight-year-olds.
The number of mobiles in Britain has doubled to 50 million since the first government-sponsored report in 2000. The number of children aged between five and nine using mobiles has increased fivefold in the same period.
In his report, Mobile Phones and Health, Sir William said that four studies have caused concern. One ten-year study in Sweden suggests that heavy mobile users are more prone to non-malignant tumours in the ear and brain while a Dutch study had suggested changes in cognitive function. A German study has hinted at an increase in cancer around base stations, while a project supported by the EU had shown evidence of cell damage from fields typical of those of mobile phones.
“All of these studies have yet to be replicated and are of varying quality but we can’t dismiss them out of hand,” Sir William said. If there was a health risk — which remained unproven — it would have a greater effect on the young than on older people, he added.
For children aged between 8 and 14, parents had to make their own judgments about the risks and benefits. “I can’t believe that for three to eight year-olds they can be readily justified,” he said.
David Hart, general secretary of the National Association of Headteachers, called last night for a ban on mobiles in schools.
Mobile phone companies reacted furiously, saying that the report fanned public concern without presenting new research. The youth market is highly lucrative because teenagers are more likely to use video downloads and other services.
The World Health Organisation is preparing to publish an international report, drawing on hundreds of studies conducted over a decade, which many hope will give a definitive judgment on mobile phone safety.
The board’s report says that while there is a lack of hard information of damage to health, the approach should be precautionary. Sir William said: “Just because there are 50 million of them out there doesn’t mean they are absolutely safe.”
One school in the North East has begun using mobile scanners to prevent pupils using mobiles in class. “Outside college hours it is up to parents, but in our care if mobiles are found on children, they are confiscated and returned to the parents,” David Riden, vice principal of Tollbar Business and Enterprise College in New Waltham, said.
One group that appears to target young users is Richard Branson’s Virgin Mobile, which derives much of its revenue from the 16s-35s market. It denies targeting under 16s but has cornered a large slice of the youth market with cheap voice and text messages.
Mobile Phone
HistoryThe mobile phone or mobile, also called a cellular phone, or cell phone is a long-range, portable electronic device used for mobile communication that uses a network of specialized base stations known as cell sites. In addition to the standard voice function of a telephone, current mobile phones can support many additional services such as SMS for text messaging, email, packet switching for access to the Internet, and MMS for sending and receiving photos and video. Most current mobile phones connect to a cellular network of base stations (cell sites), which is in turn interconnected to the public switched telephone network (PSTN) (the exception is satellite phones).
There is one U.S. patent, Patent Number 887357 for a wireless telephone, issued 1908 to Nathan B. Stubblefield of Murray, Kentucky. He applied this to "cave radio" telephones and not directly to cellular telephony as the term is currently understood.[1] However, the introduction of cells for mobile phone base stations, invented in 1947 by Bell Labs engineers at AT&T, was further developed by Bell Labs during the 1960s. Radiophones have a long and varied history going back to Reginald Fessenden's invention and shore-to-ship demonstration of radio telephony, through the Second World War with military use of radio telephony links and civil services in the 1950s, while hand-held cellular radio devices have been available since 1973. Due to their low establishment costs and rapid deployment, mobile phone networks have since spread rapidly throughout the world, outstripping the growth of fixed telephony.[citation needed]
In 1945, the zero generation (0G) of mobile telephones was introduced. 0G mobile telephones, such as Mobile Telephone Service, were not officially categorized as mobile phones, since they did not support the automatic change of channel frequency during calls, which allows the user to move from one cell (the base station coverage area) to another cell, a feature called "handover".[citation needed]
In 1984, Bell Labs invented such a "call handoff" feature, which allowed mobile-phone users to travel through several cells during the same conversation. Motorola is widely considered to be the inventor of the first practical mobile phone for handheld use in a non-vehicle setting. Using a modern, if somewhat heavy portable handset, Motorola manager Martin Cooper made the first call on a handheld mobile phone on April 3, 1973.[2]
The first commercial cellular network was launched in Japan by NTT in 1979. Fully automatic cellular networks were first introduced in the early to mid 1980s (the 1G generation) with the Nordic Mobile Telephone (NMT) system in 1981. This was followed by a boom in mobile telephone usage, particularly in Northern Europe.[citation needed]
The first "modern" network technology on digital 2G (second generation) cellular technology was launched by Radiolinja (now part of Elisa Group) in 1991 in Finland on the GSM standard which also marked the introduction of competition in mobile telecoms when Radiolinja challenged incumbent Telecom Finland (now part of TeliaSonera) who ran a 1G NMT network. A decade later, the first commercial launch of 3G (Third Generation) was again in Japan by NTT DoCoMo on the WCDMA standard.[citation needed][3] Until the early 1990s, most mobile phones were too large to be carried in a jacket pocket, so they were typically installed in vehicles as car phones. With the miniaturization of digital components, mobile phones have become increasingly portable over the years.
Today, video and TV services are driving forward third generation (3G) deployment. And in the future, low cost, high speed data will drive forward the fourth generation (4G) as short-range communication emerges. Service and application ubiquity, with a high degree of personalization and synchronization between various user appliances,will be another driver. At the same time, it is probable that the radio access network will evolve from a centralized architecture to a distributed one.
ManufacturersNokia Corporation is currently the world's largest manufacturer of mobile telephones, with a global device market share of approximately 36% in Q1 of 2007.[4] Other mobile phone manufacturers include Apple Inc., Audiovox (now UT Starcom), Benefon, BenQ-Siemens, High Tech Computer Corporation (HTC), Fujitsu, Kyocera, LG Mobile, Mitsubishi, Motorola, NEC, Neonode, Panasonic (Matsushita Electric), Pantech Curitel, Philips, Research In Motion, Sagem, Samsung, Sanyo, Sharp, Siemens, Sierra Wireless, SK Teletech, Sonim Technologies, Sony Ericsson, T&A Alcatel, and Toshiba. There are also specialist communication systems related to (but distinct from) mobile phones.
The mobile phone manufacturers can be grouped into two. The top five are available in practically all countries and comprise about 75% of all phones sold. A second tier of small manufacturers exists with phones mostly sold only in specific regions or for niche markets. The top five in order of market share are Nokia, Samsung, Motorola, SonyEricsson and LG.
Several countries, including the UK, now have more mobile phones than people.[5] There are over five hundred million active mobile phone accounts in China, as of 2007.[6] Luxembourg has the highest mobile phone penetration rate in the world, at 164% in December 2001. In Hong Kong the penetration rate reached 139.8% of the population in July 2007.[7] The total number of mobile phone subscribers in the world was estimated at 2.14 billion in 2005.[8] The subscriber count reached 2.7 billion by end of 2006 according to Informa[citation needed], and 3.3 billion by November, 2007[9], thus reaching an equivalent of over half the planet's population. Around 80% of the world's population enjoys mobile phone coverage as of 2006. This figure is expected to increase to 90% by the year 2010.[10]
At present, Africa has the largest growth rate of cellular subscribers in the world,[11] its markets expanding nearly twice as fast as Asian markets.[12] The availability of prepaid or 'pay-as-you-go' services, where the subscriber is not committed to a long term contract, has helped fuel this growth in Africa as well as in other continents.
On a numerical basis, India is the largest growth market, adding about 6 million cell phones every month.[13] With 256.55 million cell phones, market penetration in the country is still low at 22.52%. India expects to reach 500 million subscribers by end of 2010.
There are three major technical standards for the current generation of mobile phones and networks, and two major standards for the next generation 3G phones and networks. All European, African and many Asian countries have adopted a single system, GSM, which is the only technology available on all continents and in most countries and covers over 74% of all subscribers on mobile networks. In many countries, such as the United States, Australia, Brazil, India, Japan, and South Korea GSM co-exists with other internationally adopted standards such as CDMA and TDMA, as well as national standards such as iDEN in the USA and PDC in Japan. Over the past five years several dozen mobile operators (carriers) have abandoned networks on TDMA and CDMA technologies, switching over to GSM.
With third generation (3G) networks, which are also known as IMT-2000 networks, about three out of four networks are on the W-CDMA (also known as UMTS) standard, usually seen as the natural evolution path for GSM and TDMA networks. One in four 3G networks is on the CDMA2000 1x EV-DO technology. Some analysts count a previous stage in CDMA evolution, CDMA2000 1x RTT, as a 3G technology whereas most standardization experts count only CDMA2000 1x EV-DO as a true 3G technology. Because of this difference in interpreting what is 3G, there is a wide variety in subscriber counts. As of June 2007, on the narrow definition there are 200 million subscribers on 3G networks. By using the more broad definition, the total subscriber count of 3G phone users is 475 million.
While some systems of payment are 'pay-as-you-go' where conversation time is purchased and added to a phone unit via an Internet account or in shops or ATMs, other systems are more traditional ones where bills are paid by regular intervals. Pay as you go (also known as "pre-pay") accounts were invented simultaneously in Portugal and Italy and today form more than half of all mobile phone subscriptions. USA, Canada, Japan and Finland are among the rare countries left where most phones are still contract-based.
Culture and customsIn less than twenty years, the mobile telephone has gone from being rare, expensive equipment of the business elite to a pervasive, low-cost personal item. In many countries, mobile telephones outnumber land-line telephones; in the U.S., 50 percent of children have mobile telephones.[14] In many young adults' households it has supplanted the land-line telephone. The mobile phone is banned in some countries, such as North Korea.[15]
Given the high levels of societal mobile telephone service penetration, it is a key means for people to communicate with each other. The SMS feature spawned the "texting" sub-culture.[citation needed] In December 1993, the first person-to-person SMS text message was transmitted in Finland. Currently, texting is the most widely-used data service; 1.8 billion users generated $80 billion of revenue in 2006 (source ITU).
Many telephones offer Instant Messenger services for simple, easy texting. Mobile phones have Internet service (e.g. NTT DoCoMo's i-mode), offering text messaging via e-mail in Japan, South Korea, China, and India. In Europe, 30–40 per cent of internet access is via mobile telephone. Most mobile internet access is much different from computer access, featuring alerts, weather data, e-mail, search engines, instant messages, and game and music downloading; most mobile internet access is hurried and short.
The mobile telephone can be a fashion totem custom-decorated to reflect the owner's personality.[16] This aspect of the mobile telephony business is, in itself, an industry, e.g. ringtone sales exceeded $5 billion in 2006EtiquetteMobile telephone use in etiquette is an important matter of social discourtesy, phones ringing during funerals, weddings, in toilets, cinemas, and plays. Users often speak loudly, leading to book shops, libraries, bathrooms, cinemas, doctors' offices, and houses of worship prohibiting their uses, and, in some places, the installation of signal-jamming equipment to prevent their use (though in many countries, including the U.S., such equipment is currently illegal). Some new buildings, such as auditoriums, have installed wire mesh in the walls (making it a Faraday cage), which prevents signal penetration without violating signal jamming laws.
Trains, particularly those involving long-distance services, often offer a "quiet car" where phone use is prohibited, much like the designated non-smoking car in the past. However many users tend to ignore this as it is rarely enforced, especially if the other cars are crowded and they have no choice but to go in the "quiet car". Mobile phone use on aircraft is also prohibited and many airlines claim in their in-plane announcements that this prohibition is due to possible interference with aircraft radio communications. Shut-off mobile phones do not interfere with aircraft avionics. The concern about cell phones is partially based on the crash of Crossair Flight 498.
As of 2007, several airlines are experimenting with base station and antenna systems installed to the airplane, allowing low power, short-range connection of any phones aboard to remain connected to the aircraft's base station.[18] Thus, they would not attempt connection to the ground base stations as during take off and landing.[citation needed] Simultaneously, airlines may offer phone services to their traveling passengers either as full voice and data services, or initially only as SMS text messaging and similar services. Qantas, the Australian airline, is the first airline to run a test airplane in this configuration in the Autumn of 2007.[citation needed] Emirates has announced plans to allow limited mobile phone usage on some flights.[citation needed]
In any case, there are inconsistencies between practices allowed by different airlines and even on the same airline in different countries. For example, Northwest Airlines may allow the use of mobile phones immediately after landing on a domestic flight within the US, whereas they may state "not until the doors are open" on an international flight arriving in the Netherlands. In April 2007 the US Federal Communications Commission officially grounded the idea of allowing passengers to use phones during a flight.[19]
In a similar vein, signs are put up in many countries, such as Canada, The U.K. and the U.S., petrol stations prohibiting the use of mobile phones, due to possible safety issues.[citation needed] Most schools in the United States have prohibited mobile phones in the classroom, due to the large number of class disruptions that result from their use, the potential for cheating via text messaging, and the possibility of photographing someone without consent.[citation needed] In the UK, possession of a mobile phone in an examination can result in immediate disqualification from that subject or from all that student's subjects.[20]
A working group, made up of Finnish telephone companies, public transport operators and communications authorities, have launched a campaign to remind mobile phone users of courtesy, especially when using mass transit – what to talk about on the phone, and how to. In particular, the campaign wants to impact loud mobile phone usage as well as calls regarding sensitive matters.[21]
Many US cities with subway transit systems underground are studying or have implemented cell phone reception in their underground tunnels for their riders. Boston, Massachusetts has investigated such usage in their tunnels, although there is a question of usage etiquette and also how to fairly award contracts to carriers.[22]
The issue of mobile communication and etiquette has also become an issue of academic interest. The rapid adoption of the device has resulted in the intrusion of telephony into situations where this was previously not known. This has exposed the implicit rules of courtesy and opened them to reevaluation. Use by driversMobile-phone use while driving is common but controversial. While few jurisdictions have banned motorists from using mobile phones while driving outright, some have banned or restricted drivers from using hand-held mobile phones while exempting phones operated in a hands-free fashion. Using a hand-held mobile phone while driving is an impediment to vehicle operation that can increase the risk of road traffic accidents. However, some studies have found
Friday, January 18, 2008
First Laptop Computers
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.
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.
Notebook or Laptop
A laptop computer, or simply laptop (also notebook computer or notepad), is a small mobile computer, which usually weighs 2-18 pounds (around 1 to 8 kilograms), depending on size, materials, and other factors.
Laptops usually run on a single main battery or from an external AC/DC adapter which can charge the battery while also supplying power to the computer itself. Many computers also have a 3 volt cell to run the clock and other processes in the event of a power failure.
As Personal computers, laptops are capable of the same tasks as a desktop computer, although they are typically less powerful for the same price. They contain components that are similar to their desktop counterparts and perform the same functions, but are miniaturized and optimized for mobile use and efficient power consumption. Laptops usually have liquid crystal displays and most of them use different memory modules for their random access memory (RAM), for instance, SO-DIMM in lieu of the larger DIMMs. In addition to a built-in keyboard, they may utilize a touchpad (also known as a trackpad) or a pointing stick for input, though an external keyboard or mouse can usually be attached.
Terms sometimes used for subtypes of laptop computers include:
UMPCs
These Ultra-Mobile PCs are mobile computers with a size comparable to PDAs - they are extremely portable. They are now officially called notebooks as the term lap- top insinuated the laptop should be used on the lap, this however caused the hard drive to over heat thus in turn can seriously damage the computer. Because of their small size, they incorporate a 20 cm (7 inch) or smaller touch-screen for the user to interact with it (as with a virtual keyboard), though some are designed with a miniature physical keyboard (a thumbboard) and mouse interface. They house lower performing, power-saving components (in comparison to larger laptops).
Ultraportables
Laptops with screens typically less than 12 inches (30 cm) diagonally and a weight of less than 3 to 5 lb (1.4–2.3 kg). Their keyboards are usually not full-size. Their primary audience is usually business travelers, who need small, light laptops. Ultraportables are often very expensive, have extended battery life, house power-saving CPUs and almost always have integrated graphics.
Thin-and-lights
Laptops usually weighing in between 4 and 6 lb (1.8–2.7 kg) with a screen size of between 12 and 14 inches (30–35 cm) diagonally.
Mainstream
Laptops weighing in between 5 and 7 lb (2.3–3.2 kg), with a screen size of 14.1 inches and 15.4 inches (35 and 39 cm).
Desktop replacement computers
Powerful laptops meant to be mainly used in a fixed location and infrequently carried out due to their weight and size; the latter provides more space for powerful components and a big screen, usually measuring 17–20 inches (43–51 cm). Desktop replacements tend to have limited battery life, rarely exceeding three hours, because the hardware is not optimized for efficient power usage. Sometimes called a luggable laptop. An example of a desktop replacement computers are gaming notebooks, which are designed to handle 3D graphic-intensive processing for gamers.
Thursday, January 17, 2008
Network Satellite Receiver
Your new Dish Network digital high definition satellite receiver is the single most important piece of equipment in your home entertainment system. This is the 'enabler' for signals to be received from Dish Network's fleet of nine satellites in orbit around the Earth and transmitted into your home. Dish Network offers more in the way of home entertainment than any other satellite provider, and their ever-growing subscriber base of 12 million attests to this fact.
Satellite television receivers are manufactured by several companies and are easily connected to televisions. The rear panel of the receiver contains all the important features and operations of the receiver: card access, receiver identification number, AC power input, Dolby digital output, phone jack and antenna inputs, Component Video output (DVR), TV/VCR output, S-video output, and Sat In. The Sat In connects the cable from the satellite dish to the receiver. All this information is contained in the instruction manual should you ever need to install or re-install it on the occasion of moving place of residence. All the required component parts and connectors are included with your Dish Network digital high definition satellite dish.
The receiver may become overheated from time to time, losing the decoder message and on occasion it may completely expire. Overheating is caused by a surge in the receiver and can be avoided by putting two capacitors on the power supply board. This should be done rather quickly before the receiver completely stops functioning.
The main function of the Dish Network satellite television receiver is to maximize incoming digital high definition signaling from satellites. The receiver comes with many features, including an Advanced Program Guide, a Parental control, universal remote, digital audio and video output for recording, and DVR features. Whether digital or standard signaling, the receiver allows for the best transmission of signals from the satellite to your television screen.
Crystal-clear imaging and CD quality sound are produced every time you turn your television on to enjoy one of the over 256 channels of diverse programming offered by Dish Network. Dish Network features 500 commercial-free premium movies each month and 50 channels of digital Sirius music. Their programming lineup includes an offer of five different packages with something to please everyone. From sports to educational, interactive gaming with national and local weather and traffic updates, children's and adult programming, multi-cultural international channels in different languages, life-style channels, pay-per-view availability, and soon to be karaoke channeling - all for your viewing selection and enjoyment. Their free gift of a Dish Network Digital Video Recorder only enhances your viewing pleasure. It allows you to seamlessly record up to 100 hours of choice programs creating your own library of favorites - be it movies, sports events, or music. All digitally reco rded and stored on the DVR hard drive. You can record, fast-forward, rewind, and pause - even pausing live shows for interruptions. Click on Dish Network now to get more information and details of Current offers, pricing information, and instructions ordering installation.
The Dish Network digital high definition satellite receiver is the most important component followed by your choice in programming. Relax and enjoy the best advanced technology has to offer: Dish Network Satellite television services.
Capturing Special
Capturing Special Moments With A Digital Camera
There are millions of people around the world who share a keen interest in photography. The charm of capturing a moment in a camera is truly amazing. Probably, this is one of the strongest reasons why a growing number of people are joining the cult of professional photographic pursuit. Traditionally, taking photographs, film processing and developing them in the dark room was a painfully long process. But as digital technology evolved, it enabled camera manufacturing companies to come up with high-end digital cameras. Digital cameras are an ideal gadget for taking pictures without having to worry about running out of snaps of roll which is the case with the traditional film cameras. This apart, there is no need of having to wait till the entire roll of film gets used just to find the blown-up pictures in the dark room. Digital cameras allow you to take any number of photographs and see each one of them right after you take them. Also you can connect your camera to the USB port of you Personal Computer and store your snaps there in a folder. What is more is that you can customize each photograph, thru software, just the way like it. In case, you want to take a hard-copy of the pictures, you can always use the printer to get your favorite photograph printed out. Buying a digital camera is a matter of serious deliberation. Since different brands of companies are offering cameras with special features, you have be aware of the standard features of the digital cameras in order to be able to make the right purchase. The following are some of the must-know tips that you should be familiar with before you swipe you credit card in a digital camera kiosk of a shopping mall or punch in the CVV number in the box while shopping online for a captivating camera. Price Range: The price of digital photographic cameras can usually range anything from US$100 to $1000. If you are buying a digital compact camera for the first time, then don`t go for an expensive one. It is quite easy to get tempted into spending a lot of money to buy a digital SLR camera offering features that are just of no use to you. Get to know your needs and settle for a prudent purchase. Ensure that the digital camera you pick should be light-weighted and easy-to-use. Later on, after you learn the basics of digital camera photograph, you may opt for an high-end edition. Features: The standard features of digital cameras of all make are almost similar except for some special features introduced by some renowned brands in the market. Features such as zoom, automatic functions, special effects, black & white images and video recording facilities are usually offered by most brands. However, as a prudent buyer you have be careful of the claims some manufactures might be making. For instance, the feature of digital zoom magnifications may not actually live up to your expectation level if you are hoping to get the optimal clarity especially if you are aiming at say 8x10 or larger size photos. Do not be tempted by the flashy promotional gimmickry of the brands. Consider the features keeping your pre-established price range in mind. Lens: All digital cameras provide two types of zoom features: optical and digital. While the optical zoom feature is based on the lens magnification and gives you images with a sharp and crystal-clear clarity, digital zoom relies on the magnification of the digital image which results in less sharp and fuzzy images. Make sure that the digital camera you buy should at least have the optical zoom features. However, as mentioned earlier, you have to be careful of the digital zoom magnification claim. You can look for digital cameras having lens auto focus and image stabilization features. Image Resolution: Image Resolution or Pixel Resolution is one of the most striking features of digital cameras. For personal and email purpose digital cameras having 2.0 mega pixels will deliver clear photos. However, many manufactures are now offering digital cameras with 8.0 and above mega pixels. You get better and clearer images with higher mega pixels. High mega pixel resolution plays a key role in image enlargement. So if size matters to you, consider this aspect seriously. Battery Type and Longevity: If you are likely to use the digital camera for outdoor activities, it is important to consider how long the built-in batteries will last. Even if you think of using some extra rechargeable batteries, just make sure whether the digital camera you are buying support the same batteries. LCD Screen: Every digital camera has the LCD Screen feature. Just make sure that the screen size should be at least 2 inches or above. It will give you better and clear images.
Traffic Mapping
Traffic Mapping For Your Mobile Phone
In late July, Google announced that it will be offering live traffic information to mobile phones in more than thirty U.S. cities. Plans to provide the traffic feature to PCs are still in the works. The Google traffic feature will be released as an update to the free Google Maps for Mobile service, which has been available for 18 months for download on the Google web site. Google would not disclose how many subscribers it has, but it says the number is growing rapidly. The feature expands Google's mapping technology into an area where Microsoft Corp. and Yahoo already have a presence, but in different ways. Yahoo and Microsoft offer real-time traffic information on their Web-based mapping services for PCs. Microsoft has chosen to move into the mobile “space” by licensing traffic-monitoring technology for mobile devices to a Kirkland-based startup, InRix Inc. Yahoo currently has no mobile traffic service. MapQuest, an AOL property, offers traffic reports over cell phones for $2.99 per month. With typical bombast, Microsoft announced that when operable, the InRix mobile service will actually predict upcoming traffic problems – however currently the MSN mobile mapping technology provides no traffic information at all. In the cities where it works, the Google feature will show traffic conditions on most major highways - indicating green for clear roadways, yellow for medium congestion and red for high congestion or stopped traffic. Google Maps will work on most Java-enabled phones offered by Cingular and Sprint and all color BlackBerry devices. The service does not currently work on phones from other major carriers such as Verizon or T-Mobile USA. Google Maps sends the data – obtained from an undisclosed source - every five minutes. Although Google's free service doesn't identify traffic hazards or accidents, it will let drivers know if there is a clogged road. Google also shows the expected drive time for a route when phone users search for driving directions. It has introduced a feature that lets users save their favorite locations and frequently used driving directions for future use. The three search engines are not alone, however. In February, Rand McNally Traffic began offering a downloadable mobile application that delivers news of real-time traffic flow, accidents, weather conditions and road closures to 94 cities. Rand McNally Traffic is available on Sprint, Nextel, AT&T Wireless and other services for $3.99 a month. Media giant Clear Channel Communications' Total Traffic Network feeds content in 125 markets in the country to 15 services. One of them provides the information to subscribers with Sprint mobile phones for a $9.99 monthly subscription. That service is relatively new. In addition to weather conditions and traffic information, the service also provides data on gas station prices. Cell phones are rapidly turning into GPS devices, with localized information as an added feature. It remains to be seen how many people will turn to their cell phone screens for traffic news, one eye on the road and another on the phone. In some states and several local jurisdictions, it is already illegal to use a handheld cell phone while driving. Some of these jurisdictions allow hands free use, but that won’t help with a visual feature. It will be interesting to see if this new functionality is limited by governmental concern over safe driving habits.
Cell Phones for Children
There was a time that many parents balked at the idea of buying their child a cell phone. Fortunately, many now see that cell phones are the best way for your busy kids to contact you and for you to keep tabs on them. How do you choose which cell phone to buy them with all of the great options out there? It is important that you do your research and think about the needs of your child as well as what you want out of the phone. All of the companies claim to have a superior product, but you should do a little digging in order to see beyond the hype. There are several brands to choose from. Some of the most popular include: Firefly Phones Kajeet Phones LG Migo Leapfrog’s Tic Talk phone. Firefly Phones The Firefly cell phone is a great option. It is very simple to use because it actually doesn’t have a camera, MP3 player, or video. This phone doesn’t weigh very much as a direct result of losing those features. This will be a relief for many kids and parents as we are used to having to carry quite a bit for our busy lives. The Firefly kid’s cell phone has a neat display screen that will show how much battery power is left as well as the signal strength that is available. For those parents who are worried about their children answering from unknown callers, phone number ID is displayed for incoming calls. Your kids may not care so much about the actually functionality of the phone, but they’ll all want their Firefly mobile phone to look cool. There are some neat color skins that you can purchase for your kids to instantly change the look of their cell phone. The Firefly kids cell phone is a wonderful option for you if you want to have a lot of control over the phone calls your children make and receive. There is no need to worry that your child will spend hours and hours talking on their phone. Parents can control who can call in. This function offers a great piece of mind. Despite those great features, there are many people who will not be happy with the Firefly prepaid phone. It is missing many of the “cool” features your children have come to appreciate and enjoy. There is no way to organize the phone or send text messages. Kajeet Phones Another phone you may want to consider is from Kajeet phones. This phone is unique in that it was designed by parents and beta tested by kids. Many parents who’ve tested this phone have been very impressed with all that it offers. It can be very dangerous to just give your child a regular cell phone. With regular phones they can call anyone and receive calls from anyone. Kajeet phones really helps to eliminate this problem. With this phone you can set whom your kids can call. This is important if you don’t want them wasting away their minutes on calling friends for hours on end. Another neat feature is the ability to set the hours when your children can make phone calls. There are some children who will try and sneak in calls here and there at school. With Kajeet phones you can allow them to call home and 911, but block all other calls during the school day. Another great feature is that you can give your children a phone allowance. They may miss the ability to buy ringtones and other “fun” things. With Kajeet phone’s cell phone allowance they will have the ability to buy these things if you want them to. Once they’ve spent their allotment, they cannot spend any more money until you’re ready for them to. Kajeet phones are neat because they’ve really listened to their target audience and their parents. Even a quick visit to their website show that they really do pay attention to what kids in this day and age need and want. LG Migo Phone The LG Migo phone is another option in the world of cell phones for kids. It is a bright green color that will immediately attract children who want a cool looking phone to impress their friends. This phone is geared towards a slightly younger audience, which is something to keep in mind. The phone has five speed dial buttons that you can program. This is a great option for younger children who are unable to remember phone numbers. LG Migo also has a Chaperone service that is ideal for parents. The system acts as a kind of GPS device. You set the boundaries that are ok for your child to be in. If they leave that area your phone will be notified with a text message. This is something to keep in mind for safe use of cell phones for children Leapfrog’s TicTalk Phone Another entry into the world of cell phones for children is Leapfrog’s Tic Talk phone. The TicTalk phone is probably one of the most unique looking cell phones out there. It looks a bit like a stopwatch and is very durable. This is a good model for parents who are worried that their children will immediately break the phone. Leapfrog’s TicTalk phone should stand up to even the most active of children. The TicTalk works by scrolling through numbers in a phonebook. There is no dialing involved for the child. This may or may not be easy to get used to, but can actually be quite convenient once they learn the ropes. Parents set the actual phone up online. This is a great way to add convenience for those who prefer the simplicity of typing online. Kids will want to scoop Leapfrog’s TicTalk phone up because it has games on it that are pre-installed by Leapfrog. The phone is overall more full featured than some other cell phones for kids that are available today. How Should I Choose? There are many different cell phones for children that are on the market today. It is up to you and your child to decide which features are the most valuable to you. Your first priority should be the safe use of cell phones for children. Then, pick the best option for your family.
Bluetooth GPS Receiver Review
This is a tiny bluetooth GPS receiver which I bought from Mobile Fun Ltd, I bought this to connect to my O2 XDA 2i PDA and it cost around £40. I was intially looking on google for cheap GPS receivers and this came up as the cheapest. I thought at that price they'll be a catch, and the catch usually being poor performance, but I was pleasantly surprised! This thing really does work, and works well! After searching for initial reviews on this device I came up with very little other than the reviews from Mobile Fun Ltd, which I was reluctant to trust for fear of them being somewhat biased. I thought for £40 I'll take a chance and so bought it, all credit to Mobile Fun the receiver arrived the very next morning. Upon opening the box I was a little disappointed, all the there was by means of instructions was a small sheet of paper that had been loosely translated from Japanese to English by a dyslexic toddler. You can download the user manual from here and the Tomtom pairing manual from here. After following these instructions you will have it set up in no time. Another thing I noticed was that there is no manufaturer's name or marks anywhere on the device or the packaging, which makes searching for support quite difficult. A nice touch with this little device is that it is supplied with a battery that is common to a lot of Nokia phones (3.7V 850mAh Li-polymer battery, BL-5C), a quick search on ebay means that you can get replacement batteries for these receivers for about £4 which is good to know should you need one. What's In The Box? Bluetooth GPS Receiver x1 12v In Car Adapter (USB) x1 Basic Instructions x1 Battery x1 USB Charging Cable x1 Installation Provided you follow the limited instructions for pairing with your device, and the Tomtom setup instructions, you should be up and running in less than 5 minutes. I have only charged the receiver once since I bought it about 2 months ago, the battery just seems to last forever! The supplied in car charger and USB cable means that the receiver can be charged on the move from a 12v source and can also be charged from any PC or laptop. From cold start up the receiver aquires a usuable GPS signal exremely quickly, quicker than most of the really expensive GPS receivers that I've come in contact with. The device is extremely small and can easily fit into any space in your car, or even your pocket if you're using it for walking or cycling. One small problem I did have is that when using it with my XDA 2i the Tomtom software would often freeze and cause me to stop the car, reboot my phone, then carry on my journey. At first I thought this was the result of the XDA losing its connection with the bluetooth receiver and hence confirming my fears about the price of this product. It quickly became apparent that this was not the case and it was in fact an issue with my PDA and the Tomtom software. I quickly discovered a workaround for this issue between the Tomtom software and my XDA that enables the whole system to work flawlessly. I shall write a 'how to' on this workaround shortly as I'm sure many other XDA 2i users share the same problem. I do know that there is a known issue when using any bluetooth GPS receivers with the O2 XDA 2 (note not XDA 2i) due to the bluetooth stack settings that are shipped with the phone, please be aware of this before buying this device as you are sure to encounter problems. Key Features Compatible with TomTom, Navicore, and all major GPS software packages. 12 parallel satellite-tracking channels for fast acquisition and reacquisition. Provides superior navigation performance in city environments. Built-in rechargeable Lithium-polymer battery provides more than 10 hours of constant use. Unit can be charged with the included car charger while still in use. Mini-USB charger compatiblty, charge not only the Bluetooth GPS Receiver but also compatible PDAs & Smart Phones with the same charger. 3 colours LED to show the status of Bluetooth/GPS/Power activities of this device. Specifications GPS receiver: L1, C/A code, 12 channels Tracking sensitivity: –152dBm (average) or better Acquisition sensitivity: –139dBm (average) or better TTFF (Time to First Fix): Cold Start: 50s (average) / 60s (95 possibility) Hot Start: 2s (minimum) / 6s (95% possibility) Positioning accuracy: Standard Positioning Service (SPS), WAAS (optional) 2DRMS: approx. 5m Measurement data output: Update time: 1 second NMEA output protocol: V.3.01 Baud rate: 38400 bps (8-N-1) Datum: WGS-84 Type: GGA, GSA, GSV, RMC Power consumption: 75mA (average) Bluetooth: Bluetooth version 1.2 compliant Class 2 operation (up to 10 metre range) Serial Port Profile (SPP) Output terminal: Type B Mini-USB (TTL Level) Antenna Type: Built in Patch Antenna Battery: 3.7V 850mAh Li-polymer battery, built-in charger LED: Power (red), GPS (green), Bluetooth (blue) Dimension: 64(L) x 39(W) x18.5(H) mm Operating temperature: -20°C ~ +60°C Storage temperature: -20°C ~ +60°C; Battery: -20°C ~ +45°C Conclusion A great little device that performs well beyond its price range. Check if there is any known issues with your device and bluetooth GPS receivers before purchase as this will save you a lot of headaches. The only thing that lets this product down is a lack of documentation and online support, other than this well worth the buy!
Nokia 6500 Classic
A Complete Blend Of Multimedia Technology
Want a silver screen to watch movie on your palm! The Nokia 6500 Classic can offer fun imaging feature, allowing users to record, playback and stream video on the phone. Born with the best; the Nokia 6500 Classic Phone receives praises from the users because of its compact casing, 3G technology and a 2 inches QVGA LCD screen to provide sophistication while phoning, high speed broadband connection along with fast data transfer, multitasking capabilities and video streaming, and to provide excellent visual presentation respectively. Order Nokia 6500 Classic from the retailing sites to get the excellent phoning, imaging, and web browsing at an affordable price. The Nokia 6500 Classic Phone encompassed with 2-mega pixel camera and music player provides users with the ultimate imaging and music experiences. The camera can steal the show by offering beautiful images and portraying videos on the screen. The music player can soothe the minds through its tuneful sound and melodious music. As far as messaging is considered; the Nokia 6500 Classic Phone has put much emphasis on text messaging, multimedia messaging and email to assess non-verbal communication. The clarity of communication is determined with wireless connectivity and networking. Order Nokia 6500 Classic online as it does not rely on cables t download games and applications, transmit data and files, send multimedia messages and email and browse internet on the move. In fact, the Nokia 6500 Classic Phone supports Bluetooth, USB, EDGE, Quad Band technology, HSCSD, WAP and XHTML to render wire free communication in the form of multimedia and mobile computing. When multimedia communication is at its offing; the introduction of the Nokia 6500 Classic Phone has set a new trend of communication to develop computer-generated performance on the mobile phone. In short, the Nokia N6500 Classic is regarded as a sophisticated device designed with all the latest technology you could need.
What Satellite TV Can Offer You?
Do you know what are the offers that satellite tv gives you? It will definitely give you and your family more fun and excitement. Not only that you can watch hundreds of channels, complete movie and sports packages, but also those channels that are available from across the country or even across the globe. There are times when you are so much busy and you intend to miss your favorite show. That show may be your ever favorite and you haven't miss any episode of it in your entire life. But with satellite tv, you better not to worry at all. Because you could have both the East Coast and the West Coast versions of a channel so you can watch it later. Compare to cable tv, satellite tv offers many more channels with some packages and hundreds more of channels. Other than that, we all know that cable is not available in some areas in the country. And sure you don't like that. Of course you can't stick watching with just one channel and you definitely want to have more. Satellite tv is one great choice. Unlike with cable, which typically only has one provider per area, in sateliite tv you can choose from any number of satellite television providers. Although for some reasons, cable tv may have its advantages, but some of cable customers actually experience more frequent loss of their programming than satellite television customers. And charges for installation for hooking the cable up to more than one TV. So that's not good to hear right? Yes there are so many satellite tv providers out there, but which one would you choose? We all know that competitions are every where and it is also common in choosing satellite tv providers. But you don't have to worry, you will surely get a better price, more than what cable tv can offer. Just try to ask these questions: First, are there channels that are not available in cable that you really want? Second, are there shows that you are craving to watch and you don't want to miss any episode on them? And lastly, are you willing to pay extra for local channels or can you find a satellite television package that includes them at no extra cost? Think about it. Everywhere, there are reviews from different consumer that you can find from magazines, internet and many other. Reviews of the top satellite television provider such as Dish Network. Reviews from fellow consumers will make you easy to decide. Choosing satellite tv from any of its providers will always assure you to enjoy and love what you are watching. You can get you favorite channels such as, family channels, movie channels, sports channels, international channels, HDTV channels and even more. Satellite tv has all these that you will watch and sure you'll not gonna let them go away.
Tuesday, January 15, 2008
Wireless
Wireless was the next significant step in telecommunication after the telephone. Scientists and engineers began to fathom electromagnetic waves, they also discovered how to manipulate and exploit them. This success meant that you didn't need to have a physical connection between the sender and the receiver, enabling you to send information across huge distances - around the world, or even across space.Wireless works because an electromagnetic wave, passing through the air at the speed of light, can create - or 'induce' - an electrical signal in an aerial. If you can control this electromagnetic wave, then you can use it to communicate or to broadcast information.So in a radio system, information is sent from one place - the transmitter - and picked up in another - the receiver - using an electromagnetic wave to carry it.
When scientists first realised that electromagnetic waves could be transmitted through the air, they didn't understand the full extent or impact of what they'd discovered. As our knowledge of the electromagnetic spectrum and the properties of electromagnetic waves has increased, we have learnt to manipulate and exploit them in different ways for many different uses, from early transatlantic phone calls to today's satellite and mobile communications.
sAlthough you can communicate over long distances with wireless, there are limits because the Earth's surface is curved and electromagnetic waves may be lost before reaching their intended destination. The solution to these limitations is to use communication satellites high above the Earth's surface to relay information around the world. Although there are now hundreds of satellites in orbit around the Earth, this scientific solution to the problem of long distance communication was thought up many years before the technology existed to achieve it.
phonesMobiles phones have changed our lives since the first ones appeared in 1985. Today's mobile phones are triumphs of miniaturisation - there's nothing else you own that's likely to fit so much technology into such a small package. It's a great combination of electronics and design, but what makes it work behind the scenes is just as important. The widespread use of mobile phones has meant huge additions to the old telephone system in the form of base stations, transmitters and antenna towers, as well as clever techniques for getting the most out of the electromagnetic spectrum. And the network also has to know where you are . . . .
Mobile telephone networks are organised in geographic cells, and each cell has an antenna that transmits to all the mobile phones that are in its geographic area. For this reason the network must know exactly where you are as you move around.
When you move from one cell to another your identity (which is contained inside your SIM card) and your new location are automatically reported to the network's control system. Your telephone also 'reports in' to the local network every couple of minutes. You can sometimes hear the communication, as interference, if your mobile is near a loudspeaker or landline telephone.
Conversations on the move are transferred without a break from one base station to the next. And because the network knows at all times where you are (as long as you're in range of one of its base stations and switched on), you can always be contacted if someone calls you.
Each network operator - such as Vodafone, 02, Orange and so on - has been given a share of the electromagnetic spectrum - a band of frequencies - for their network and their customers. But this band is not enough to give everyone a permanent connection, so advanced techniques are used to make sure that it's all being used as well as it can be, to ensure there's a slot available when you want to make a call.
When you make a call you're allocated a channel - a small part of the frequency band - but it's not permanent. When you move around and change from one cell to another this frequency may not be available, so you are changed to a vacant slot. And when you finish the call, the slot you've been using is made available for someone else. This is called frequency reuse and the concept forms the basis of having a workable cellular system. Unfortunately there's a fixed maximum capacity for each cell so sometimes you can't get a connection when all frequecy slots are already in use.
Telecommunication
The telephone came about as scientists tried to squeeze more out of the telegraph. They began to understand how to influence sound, and how to send it over longer and longer distances to more and more people. Although the telephone itself hasn't really changed much in the last hundred years - and the telegraph's 'ons' and 'offs' live on in the binary codes used by today's digital technology - considerable adaption was needed to accomodate new devices like fax machines and modems.
The telephone combined the knowledge of how sound works together with a variable electric signal that could be sent over great distances. Instead of the telegraph's simple electrical pulse - on or off - the telephone uses an electrical signal that changes in amplitude (volume) and frequency (pitch) across time - in other words, a 'continuously varying signal'. This is more like real life, and means that the telephone is able to carry a human voice. But for the scientists of the day it required a better understanding of electricity as well as technological progress in the areas of cables and switches.
The sound waves that you hear are quite simply movements or vibrations of air. These sound waves travel through air, like the wind, by changes in air pressure.
Different sounds come about because the air vibrates at different frequencies. And as the trailer for the film 'Alien' made clear - 'in space, no-one can hear you scream ...' - sound can't travel in a vacuum because there's no air.
The substance that a sound wave travels through is called its 'transmission medium'. Sound waves can, in fact, travel through almost any medium, such as water or the bricks in your house, and in many cases much further than in air. Whale songs can travel for hundreds of miles underwater, although you'd need special equipment to listen to them if you were more than about 10 miles away.
Cables and wires are the unsung heroes or 'facilitators' of the age of telecommunication. In the space of twenty years, cables changed from two mile long wooden troughs containing copper wire in grooves to cables that could be laid underwater across the Atlantic. This required enormous technological feats. Perhaps more surprisingly, copper cables have also stood the test of time, as scientists and engineers have developed techniques to squeeze more and more out of them.
The complexity of a network - telephone or computer - rises dramatically with the number of people connected to it. This was not something that had bothered people until the telephone became widespread, when it suddenly became really important. If there are only a few people with telephones, the network is quite simple and everyone can be connected to everyone else. If there are more people, you need some sort of exchange to connect a call to another person through a central system. But if there are thousands of people it gets much more complicated
One thing that has extended the use of the telephone system is the way that new machines, like computers and faxes, have been connected to the existing network - the cables and exchanges that form the telephone infrastructure. To take advantage of this infrastructure, the machines are designed to work with the existing system. This means that the signals have to be in a range that the telephone wire can handle. As the telephone is designed to carry speech, you can hear strange whistling sounds coming out of modems and fax machines - they are communicating with each other in the range of the human ear.
Pioneer Digital Phone
Another secret wartime computer whose existence was finally revealed many years later was SIGSALY - the secret 'scrambling' system devised to protect the security of high level Allied telephone traffic.
SIGSALY - originally codenamed Project X - was also known as 'Green Hornet'. It was the first unbreakable speech coding system, using digital cryptography techniques, with one time digital keys being supplied by synchronised gramophone discs.
SIGSALY was built in the USA, though using pulse code modulation (PCM) digital encoding techniques invented in 1937 by the English engineer Alec Reeves.
The first priority was to protect the hotline between the Cabinet War Room bunker under Downing Street and the White House in Washington D.C. The 50-ton London terminal was shipped over in 1943 and housed in the basement of the Selfridges annexe in Oxford Street, under tight guard.
Colossus
During the Second World War the Germans used a Lorenz encoding teleprinter to transmit their high-command radio messages. The teleprinter used something called the 5-bit Baudot code, which enciphered the original text by adding to it successively two characters before transmission. The same two characters were applied to the received text at the other end to reveal the original message.
Gilbert Vernam had developed this scheme in America, using two synchronised tapes to generate the additional random characters. Lorenz replaced the tapes with mechanical gearing - so it wasn't a genuinely random sequence - just extremely complex.
But in August 1941 the Germans made a bad mistake. A tired operator sent almost the same message again, using the same wheel settings. It meant the British were able to calculate the logical structure inside the Lorenz.
Colossus was then built to find the Lorenz wheel settings used for each message, using a large electronic programmable logic calculator, driven by up to 2,500 thermionic valves. The computer was fast, even by today's standards. It could break the combination in about two hours - the same as today's modern Pentium PC.
First Computer
By designing a huge machine now generally regarded as the world's first programmable electronic computer, the then Post Office Research Branch played a crucial but secret role in helping to win the Second World War. The purpose of Colossus was to decipher messages that came in on a German cipher machine, called the Lorenz SZ.
The original Colossus used a vast array of telephone exchange parts together with 1,500 electronic valves and was the size of a small room, weighing around a ton. This 'string and sealing wax affair' could process 5,000 characters a second to run through the many millions of possible settings for the code wheels on the Lorenz system in hours - rather than weeks.
Both machines were designed and constructed by a Post Office Research team headed by Tommy Flowers at Dollis Hill and transported to the secret code-breaking centre at Bletchley Park, near Milton Keynes, where it was demonstrated on December 8, 1943. We have to fast forward nearly thirty years to 1972 for the arrival of the first desktop all-in-one computer, which are more familar to us today. That honour falls to the HP9830. But unfortunately few people got to hear about it because Hewlett Packard marketed it primarily to scientists and engineers - by nature very quiet people!
Monday, January 14, 2008
Computer history
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Computers take numerous physical forms. 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. Modern computers are based on comparatively tiny integrated circuits and are millions to billions of times more capable while occupying a fraction of the space. 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 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 capa
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. Examples of early mechanical computing 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. 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.
In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer that he called "The Analytical Engine".[3] 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.
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.Microprocessors are miniaturized devices that often implement stored program CPUs.Vacuum tube-based computers were in use throughout the 1950s, but were largely replaced in the 1960s by transistor-based devices, which were smaller, faster, cheaper, used less power and were more reliable. These factors allowed computers to be produced on an unprecedented commercial scale. By the 1970s, the adoption of integrated circuit technology and the subsequent creation of microprocessors such as the Intel 4004 caused another leap in size, speed, cost and reliability. By the 1980s, computers had become sufficiently small and cheap to replace simple mechanical controls in domestic appliances such as washing machines. Around the same time, computers became widely accessible for personal use by individuals in the form of home computers and the now ubiquitous personal computer. In conjunction with the widespread growth of the Internet since the 1990s, personal computers are becoming as common as the television and the telephone and almost all modern electronic devices contain a computer of some kind.
