Today i just give some random thoughts, actually as usual

I'm really quite fascinated by the traffic. The turning for example is special. In most countries you just do a 90° turn if you wanna go right or left, here it's different. If you wanna turn left you need to pass the oncoming traffic. To stop here wait for a gap or that people let you pass just doesn't works. So what you do here is that you start turning at the beginning of the junction in a 30° angle while doing so you make your way through the oncoming traffic. They will go around you, just don't be affraid. Sometimes you have to go slower, sometimes to accelerate. If you wanna be a bit more local, than press th honk while turning at least several times. But this multitasking can be difficult, especially for the male fraction... And always remember the right of way goes from big to small. Cars before bikes, and thebigger they are the more/stronger rights they have!

Yesterday i went out to have fundives, not to work. Here are around twelve divingclubs, but one of them are really nice, friendly people and good diver as well. They invited me to come with them and i did. Been to the only reef here where it is for normal people allowed to dive and did three dives. Was quite nice, the visibility was all right and they dives have been relaxed. The coral reefs here are not as good as on other places, but you can still see some nice things (small sized) and if you into corals, you also will get one's money's worth.

The Vietnamse Guide was really good, i think is one of the best divers i ever met and he has eyes which are unbelievable. He sees and finds things.... E.g  he spotted a flunder which  layed around 15 meters away on the sand (really good camouflaged) and not even in our direction... so we saw among other things ghost pipefishes, stonefishes and a frogfish which is not common here.

In the evening we had a Vietnames BBQ with them and after that we went in a bar to have a drink. Due to the outside life here you sit (at least in Vietnamese places) on the small chairs, which i mentioned before. So while we drunk the police showed up. Actually  they drive a small truck and they are sitting on the truck rack. Because you are only allowed to take for your business half of the footpath you allways need to watch for the police. So this time they have been spotted to late, so at the time they jumped of the truck everybody got up, took they chairs and tables and tried to hide them or put them into the shop. Because the police takes everything what is on the wrong half of the footpath. We only lost one chair to them, other groups lost a lot more

They just pick them up put 'em on their truck rack and take off. I heard you can go to their depot and get your stuff back against a nice paiment. But to buy it new is cheaper

So thats for today, keep looking up if you're interested and if you like add a comment, because is also nice to see what people thinking while reading the text....

This article compares the IBM compatible personal computer motherboard form factors – that is, the different sizes and specific or de-facto standards of major system components. In all cases, at least the motherboard footprint, mounting, and connectorization is specified. Less frequently, dimensions for cases and power supplies is also standardized. Power supply voltages and current requirements may also be given.

The specifications are considered a form factor (as opposed to a model) when enough information is available so that FRU-level parts can be sourced from more than one OEM.

There are actually many computer form factors. These can generally be classified according to category of application (especially in embedded systems) or by architecture (e.g. CHRP). However, this comparison is limited to ISA (IBM compatible) PC architectures, compatible evolutions of it (legacy-free), or form factors that have evolved to accommodate ISA-compatible CPUs (e.g. -ITX and ETX).

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Overview of form factors

Pictorial comparison of some common computer form factors.

A PC motherboard is the main circuit board within a typical desktop computer, laptop or server. It has a number of functions of which the main ones are:

• As a central backbone to which all other modular parts (CPU, RAM, hard drives etc) can be attached as required to create a modern computer
• To accept (on many motherboards) different components (in particular CPU and PCI cards) for the purposes of customization.
• To distribute power to many of the PC components
• To electronically co-ordinate the operation of these, and interface all of these with one another.

As new generations of components have been developed, the standards of motherboards have changed too - for example with AGP being introduced, and more recently PCI Express. However the basic standardized size and layout of motherboard have changed much more slowly, and are controlled by their own standards. This is helped by the fact that in many ways, the list of components a motherboard must include changes far slower than the components themselves. For example, north bridge controllers have changed many times since their original introduction, with many manufacturers bringing out their own versions, but in terms of form factor standards, the requirement to allow for a north bridge has remained fairly static for many years.

Although it is a slower process, form factors do evolve regularly in response to changing demands. The original PC standard (AT) was superseded in 1995 by the current industry standard ATX, which still dictates the size and design of the motherboard in most modern PCs. The latest update to the ATX standard was released in 2004. A divergent standard by chipset manufacturer VIA called EPIA (aka -ITX, and not to be confused with EPIC) is based upon smaller form factors and its own standards.

Differences between form factors are most apparent in terms of their intended market sector, and involve variations in size, design compromises and typical features. Most modern computers have very similar requirements, so form factor differences tend to be based upon subsets and supersets of these. For example, a desktop computer may require more sockets for maximal flexibility and many optional connectors and other features on-board, whereas a computer to be used in a multimedia system may need to be optimized for heat and size, with additional plug-in cards being less common. The smallest motherboards may sacrifice CPU flexibility in favor of a fixed manufacturer's choice.

Comparisons

Tabular information

Please help improve this article or section by expanding it. Further information might be found on the talk page or at requests for expansion. (November 2007)

Graphical comparison of physical sizes

This image compares the sizes of common form factors to ISO 216 paper sizes (e.g. A4) (Sizes are in mm):

Visual examples of different form factors

Example images of different form factors

ATX (Abit KT7)

mini-ITX (VIA EPIA 5000AG)

Pico-ITX (VIA EPIA PX10000G)

PC/104 and EBX

PC/104 is an embedded computer standard which defines both a form factor and computer bus. PC/104 is intended for embedded computing environments. Single board computers built to this form factor are often sold by COTS vendors, which benefits users who want a customized rugged system, without months of design and paper work.

The PC/104 form factor was standardized by the PC/104 Consortium in 1992.[3] An IEEE standard corresponding to PC/104 was drafted as IEEE P996.1, but never ratified.

The 5.75 x 8.0 in. Embedded Board eXpandable (EBX) specification, which was derived from Ampro's proprietary Little Board form-factor, resulted from a collaboration between Ampro and Motorola Computer Group.

As compared with PC/104 modules, these larger (but still reasonably embeddable) SBCs tend to have everything of a full PC on them, including application oriented interfaces like audio, analog, or digital I/O in many cases. Also it's much easier to fit Pentium CPUs -- whereas it's a tight squeeze (or expensive) to do so on a PC/104 SBC. Typically, EBX SBCs contain: the CPU; upgradeable RAM subassemblies (e.g. DIMM); Flash memory for solid state disk; multiple USB, serial, and parallel ports; onboard expansion via a PC/104 module stack; off-board expansion via ISA and/or PCI buses (from the PC/104 connectors); networking interface (typically Ethernet); and video (typically CRT, LCD, and TV).

Mini PC

Mini PC is a PC form factor very close in size to an external CD or DVD drive.

Varifocal Lens

Toner Catridge

Toy Telescope

vedio camera

Head Magnifier

HP C8728A

Folding Magnifier

Educational Microscope

Pen Cameras

Reversing Cameras

Playstation Lens

caf2 lens

Flat Magnifier

canon cl41

laboratory microscope

Motorola Lens

led magnifier

ophthalmic instrument

optical pick-up

optical jumper

nutri guide

optical pickup

optical prisms

xerox c525a

Zoom Microscope

Auto reset

auto lensmeter

Stereoscopic Microscope

frame warmer

carbonless copy

A basic calculator

An old mechanical calculator.

A scientific calculator.

Modern electronic calculators are generally small, digital, (often pocket-sized) and usually inexpensive. In addition to general purpose calculators, there are those designed for specific markets; for example, there are scientific calculators which focus on advanced math like trigonometry and statistics, or even have the ability to do computer algebra. Modern calculators are more portable than most computers, though most PDAs are comparable in size to handheld calculators.

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Overview

In the past, mechanical clerical aids such as abaci, comptometers, Napier's bones, books of mathematical tables, slide rules, or mechanical adding machines were used for numeric work. This semi-manual process of calculation was tedious and error-prone.

Modern calculators are electrically powered (usually by battery and/or solar cell) and vary from cheap, give-away, credit-card sized models to sturdy adding machine-like models with built-in printers. They first became popular in the late 1960s as decreasing size and cost of electronics made possible devices for calculations, avoiding the use of scarce and expensive computer resources. By the 1980s, calculator prices had reduced to a point where a basic calculator was affordable to most. By the 1990s they had become common in math classes in schools, with the idea that students could be freed from basic calculations and focus on the concepts.

Computer operating systems as far back as early Unix have included interactive calculator programs such as dc and hoc, and calculator functions are included in almost all PDA-type devices (save a few dedicated address book and dictionary devices).

Use in education

In most countries, students use calculators for schoolwork. There was some initial resistance to the idea out of fear that basic arithmetic skills would suffer. There remains disagreement about the importance of the ability to perform calculations by hand or "in the head", with some curricula restricting calculator use until a certain level of proficiency has been obtained, while others concentrate more on teaching estimation techniques and problem-solving. Research suggests that inadequate guidance in the use of calculating tools can restrict the kind of mathematical thinking that students engage in.^[1] Others have argued that calculator use can even cause core mathematical skills to atrophy, or that such use can prevent understanding of advanced algebraic concepts.

There are other concerns - for example, that a pupil could use the calculator in the wrong fashion but believe the answer because that was the result given. Teachers try to combat this by encouraging the student to make an estimate of the result manually and ensuring it roughly agrees with the calculated result. Also, it is possible for a child to type in −1 × −1 and obtain the correct answer '1' without realizing the principle involved. In this sense, the calculator becomes a crutch rather than a learning tool, and it can slow down students in exam conditions as they check even the most trivial result on a calculator.

Other concerns on usage

Errors are not restricted to school pupils. Any user could carelessly rely on the calculator's output without double-checking the magnitude of the result — i.e., where the decimal point is positioned. This problem was all but nonexistent in the era of slide rules and pencil-and-paper calculations, when the task of establishing the magnitudes of results had to be done by the user. In addition, algorithmic flaws and rounding techniques can sometimes lead to minor precision errors.^[2]

Some fractions such as 2/3 are awkward to display on a calculator display as they are usually rounded to 0.66666667. Also, some fractions such as 1/7 which is 0.14285714285714 can be difficult to recognize in decimal form; as a result, many scientific calculators are able to work in vulgar fractions and/or mixed numbers.

Calculating vs. computing

The fundamental difference between calculators and computers is that computers can be programmed to perform different tasks while calculators are pre-designed with specific functions built in, for example addition, multiplication, logarithms, etc. While computers may be used to handle numbers, they can also manipulate words, images or sounds and other tasks they have been programmed to handle. However, the distinction between the two is quite blurred; some calculators have built-in programming functions, ranging from simple formula entry to full programming languages such as RPL or TI-BASIC. Graphing calculators in particular can, along with PDAs, be viewed as direct descendants of the 1980s pocket computers, essentially calculators with full keyboards and programming capability.

The market for calculators is extremely price-sensitive, to an even greater extent than the personal computer market; typically the user desires the least expensive model having a specific feature set, but does not care much about speed (since speed is constrained by how fast the user can press the buttons). Thus designers of calculators strive to minimize the number of logic elements on the chip, not the number of clock cycles needed to do a computation.

For instance, instead of a hardware multiplier, a calculator might implement floating point mathematics with code in ROM, and compute trigonometric functions with the CORDIC algorithm because CORDIC does not require hardware floating-point. Bit serial logic designs are more common in calculators whereas bit parallel designs dominate general-purpose computers, because a bit serial design minimizes the chip complexity, but takes many more clock cycles. (Again, the line blurs with high-end calculators, which use processor chips associated with computer and embedded systems design, particularly the Z80, MC68000, and ARM architectures, as well as some custom designs specifically made for the calculator market.)

Personal computers and personal digital assistants can perform general calculations in a variety of ways:

• Most computer operating systems, at least those that support some kind of multitasking, include calculator programs, both text mode (such as the Unix bc (1) language) and graphical mode (Mac OS Calculator, Microsoft Calculator, KCalc, Grapher). Most, though not all, imitate the interface of a physical calculator. Some shell programs and interpreted programming languages also provide interactive calculation functions.
• For more complex calculations requiring large amounts of organized data, spreadsheet programs such as Excel or OpenOffice.org Calc provide calculation and sometimes reporting functions.
• Computer algebra programs such as Mathematica, and others can handle advanced calculations.
• Client-side scripting can be used for calculations, e.g. by entering "javascript:alert('calculation written in JavaScript')" in a web browser's address bar (as opposed to "http://website name"). Such calculations can be embedded in a separate Javascript or HTML file as well.
• Online calculators such as the calculator feature of the Google search engine can perform calculations server-side.

History

Origin: the abacus

Chinese abacus.

Main article: Abacus

The first calculators were abaci, and were often constructed as a wooden frame with beads sliding on wires. Abacuses were in use centuries before the adoption of the written Arabic numerals system and are still used by some merchants, fishermen and clerks in China and elsewhere.

Other early calculators

Devices have been used to aid computation for thousands of years, using one-to-one correspondence with our fingers.^[3] The earliest counting device was probably a form of tally stick. Later record keeping aids throughout the Fertile Crescent included clay shapes, which represented counts of items, probably livestock or grains, sealed in containers.^[4] The abacus was used for arithmetic tasks. The Roman abacus was used in Babylonia as early as 2400 BC. Since then, many other forms of reckoning boards or tables have been invented. In a medieval counting house, a checkered cloth would be placed on a table, and markers moved around on it according to certain rules, as an aid to calculating sums of money (this is the origin of "Exchequer" as a term for a nation's treasury).

A number of analog computers were constructed in ancient and medieval times to perform astronomical calculations. These include the Antikythera mechanism and the astrolabe from ancient Greece (c. 150-100 BC), which are generally regarded as the first mechanical analog computers.^[5] Other early versions of mechanical devices used to perform some type of calculations include the planisphere and other mechanical computing devices invented by Abū Rayhān al-Bīrūnī (c. AD 1000); the equatorium and universal latitude-independent astrolabe by Abū Ishāq Ibrāhīm al-Zarqālī (c. AD 1015); the astronomical analog computers of other medieval Muslim astronomers and engineers; and the astronomical clock tower of Su Song (c. AD 1090) during the Song Dynasty. The "castle clock", an astronomical clock invented by Al-Jazari in 1206, is considered to be the earliest programmable analog computer.^[6]

Scottish mathematician and physicist John Napier noted multiplication and division of numbers could be performed by addition and subtraction, respectively, of logarithms of those numbers. While producing the first logarithmic tables Napier needed to perform many multiplications, and it was at this point that he designed Napier's bones, an abacus-like device used for multiplication and division.^[7] Since real numbers can be represented as distances or intervals on a line, the slide rule was invented in the 1620s to allow multiplication and division operations to be carried out significantly faster than was previously possible.^[8] Slide rules were used by generations of engineers and other mathematically inclined professional workers, until the invention of the pocket calculator. The engineers in the Apollo program to send a man to the moon made many of their calculations on slide rules, which were accurate to three or four significant figures.^[9]

German polymath Wilhelm Schickard built the first digital mechanical calculator in 1623, and thus became the father of the computing era.^[10] Since his calculator used techniques such as cogs and gears first developed for clocks, it was also called a 'calculating clock'. It was put to practical use by his friend Johannes Kepler, who revolutionized astronomy when he condensed decades of astronomical observations into algebraic expressions. An original calculator by Pascal (1640) is preserved in the Zwinger Museum. Machines by Blaise Pascal (the Pascaline, 1642) and Gottfried Wilhelm von Leibniz (1671) followed. Leibniz once said "It is unworthy of excellent men to lose hours like slaves in the labour of calculation which could safely be relegated to anyone else if machines were used."^[11]

The 17th century

In 1622 William Oughtred invented the slide rule, which was revealed by his student Richard Delamain in 1630.^[12] Wilhelm Schickard built what may have been the first mechanical calculator in 1623. He called it the "Calculating Clock". ^[13] Some 20 years later, in 1643, French philosopher Blaise Pascal invented the calculation device later known as the Pascaline, which was used for taxes in France until 1799. The German philosopher G.W.v. Leibniz also produced a calculating machine.

The 19th century

The London Science Museum's working difference engine, built from Charles Babbage's design.

• In 1822 Charles Babbage proposed a mechanical calculator, called a difference engine, which was capable of holding and manipulating seven numbers of 31 decimal digits each. Babbage produced two designs for the difference engine and a further design for a more advanced mechanical programmable computer called an analytical engine. None of these designs were completely built by Babbage. In 1991 the London Science Museum followed Babbage's plans to build a working difference engine using the technology and materials available in the 19th century.
• In 1853 Per Georg Scheutz completed a working difference engine based on Babbage's design. The machine was the size of a piano, and was demonstrated at the Exposition Universelle in Paris in 1855. It was used to create tables of logarithms.
• In 1872, Frank Baldwin in the U.S.A. invented the pinwheel calculator, which was also independently invented two years later by W.T. Odhner in Russia. The Odhner models, and similar designs from other companies, sold many thousands into the 1970s.
• In 1875 Martin Wiberg re-designed the Babbage/Scheutz difference engine and built a version that was the size of a sewing machine.
• Dorr E. Felt, in the U.S.A., invented the Comptometer in 1884, the first successful key-driven adding and calculating machine ["key-driven" refers to the fact that just pressing the keys causes the result to be calculated, no separate lever has to be operated]. In 1886 he joined with Robert Tarrant to form the Felt & Tarrant Manufacturing Company which went on to make thousands of Comptometers.
• In 1891 William S. Burroughs began commercial manufacture of his printing adding calculator. Burroughs Corporation became one of the leading companies in the accounting machine and computer businesses.
• The "Millionaire" calculator was introduced in 1893. It allowed direct multiplication by any digit - "one turn of the crank for each figure in the multiplier".

1900s to 1960s

Mechanical calculators reach their zenith

Mechanical calculator from 1914

The first half of the 20th century saw the gradual development of the mechanical calculator mechanism.

The Dalton adding-listing machine introduced in 1902 was the first of its type to use only ten keys, and became the first of many different models of "10-key add-listers" manufactured by many companies.

An Addiator could be used for addition and subtraction.

In 1948 the miniature Curta calculator, that was held in one hand for operation, was introduced after being developed by Curt Herzstark in a Nazi concentration camp. This was an extreme development of the stepped-gear calculating mechanism.

From the early 1900s through the 1960s, mechanical calculators dominated the desktop computing market (see History of computing hardware). Major suppliers in the USA included Friden, Monroe, and SCM/Marchant. (Some comments about European calculators follow below.) These devices were motor-driven, and had movable carriages where results of calculations were displayed by dials. Nearly all keyboards were full — each digit that could be entered had its own column of nine keys, 1..9, plus a column-clear key, permitting entry of several digits at once. (See the illustration of a 1914 mechanical calculator.) One could call this parallel entry, by way of contrast with ten-key serial entry that was commonplace in mechanical adding machines, and is now universal in electronic calculators. (Nearly all Friden calculators had a ten-key auxiliary keyboard for entering the multiplier when doing multiplication.) Full keyboards generally had ten columns, although some lower-cost machines had eight. Most machines made by the three companies mentioned did not print their results, although other companies, such as Olivetti, did make printing calculators.

In these machines, Addition and subtraction were performed in a single operation, as on a conventional adding machine, but multiplication and division were accomplished by repeated mechanical additions and subtractions. Friden made a calculator that also provided square roots, basically by doing division, but with added mechanism that automatically incremented the number in the keyboard in a systematic fashion. Friden and Marchant (Model SKA) made calculators with square root. Handheld mechanical calculators such as the 1948 Curta continued to be used until they were displaced by electronic calculators in the 1970s.

Facit NTK (1954)

Triumphator CRN1 (1958)

Walther WSR160 (1960)

Olivetti Divisumma 24 (1964)

The Facit, Triumphator, and Walther calculators are typical European machines. Similar-looking machines included the Odhner and Brunsviga. Although these are operated by handcranks, there were motor-driven versions. Most machines that look like these use the Odhner mechanism, or variations of it. The Olivetti Divisumma did all four basic operations of arithmetic, and has a printer. Full-keyboard machines, including motor-driven ones, were also used in Europe for many decades. Some European machines had as many as 20 columns in their full keyboards.

The development of electronic calculators

The first main-frame computers, using firstly vacuum tubes and later transistors in the logic circuits, appeared in the late 1940s and 1950s. This technology was to provide a stepping stone to the development of electronic calculators.

In 1954, IBM, in the U.S.A., demonstrated a large all-transistor calculator and, in 1957, the company released the first commercial all-transistor calculator, the IBM 608, though it was housed in several cabinets and cost about $80,000.^[14]

The Casio Computer Co., in Japan, released the Model 14-A calculator in 1957, which was the world's first all-electric "compact" calculator. It did not use electronic logic but was based on relay technology, and was built into a desk.

In October 1961, the world's first all-electronic desktop calculator, the Bell Punch/Sumlock Comptometer ANITA (A New Inspiration To Arithmetic/Accounting) was announced.^[15][16] This British designed-and-built machine used vacuum tubes, cold-cathode tubes and Dekatrons in its circuits, with 12 cold-cathode "Nixie"-type tubes for its display. Two models were displayed, The Mk VII for continental Europe and the Mk VIII for Britain and the rest of the world, both for delivery from early 1962. The Mk VII was a slightly earlier design with a more complicated mode of multiplication and was soon dropped in favour of the simpler Mark VIII version. The ANITA had a full keyboard, similar to mechanical Comptometers of the time, a feature that was unique to it and the later Sharp CS-10A among electronic calculators. Bell Punch had been producing key-driven mechanical calculators of the Comptometer type under the names "Plus" and "Sumlock", and had realised in the mid-1950s that the future of calculators lay in electronics. They employed the young graduate Norbert Kitz, who had worked on the early British Pilot ACE computer project, to lead the development. The ANITA sold well since it was the only electronic desktop calculator available, and was silent and quick.

The tube technology of the ANITA was superseded in June 1963, by the U.S. manufactured Friden EC-130, which had an all-transistor design, 13-digit capacity on a 5-inch CRT, and introduced reverse Polish notation (RPN) to the calculator market for a price of $2200, which was about triple the cost of an electromechanical calculator of the time. Like Bell Punch, Friden was a manufacturer of mechanical calculators that had decided that the future lay in electronics. In 1964 more all-transistor elctronic calculators were introduced: Sharp introduced the CS-10A, which weighed 25 kg (55 lb) and cost 500,000 yen (~US$2500), and Industria Macchine Elettroniche of Italy introduced the IME 84, to which several extra keyboard and display units could be connected so that several people could make use of it (but apparently not at the same time).

There followed a series of electronic calculator models from these and other manufacturers, including Canon, Mathatronics, Olivetti, SCM (Smith-Corona-Marchant), Sony, Toshiba, and Wang. The early calculators used hundreds of Germanium transistors, since these were then cheaper than Silicon transistors, on multiple circuit boards. Display types used were CRT, cold-cathode Nixie tubes, and filament lamps. Memory technology was usually based on the delay line memory or the magnetic core memory, though the Toshiba "Toscal" BC-1411 appears to use an early form of dynamic RAM built from discrete components. Already there was a desire for smaller and less power-hungry machines.

The Olivetti Programma 101 was introduced in late 1965; it was a stored program machine which could read and write magnetic cards and displayed results on its built-in printer. Memory, implemented by an acoustic delay line, could be partitioned between program steps, constants, and data registers. Programming allowed conditional testing and programs could also be overlaid by reading from magnetic cards. It is regarded as the first personal computer produced by a company (that is, a desktop electronic calculating machine programmable by non-specialists for personal use). The Olivetti Programma 101 won many industrial design awards.

The Monroe Epic programmable calculator came on the market in 1967. A large, printing, desk-top unit, with an attached floor-standing logic tower, it was capable of being programmed to perform many computer-like functions. However, the only branch instruction was an implied unconditional branch (GOTO) at the end of the operation stack, returning the program to its starting instruction. Thus, it was not possible to include any conditional branch (IF-THEN-ELSE) logic. During this era, the absence of the conditional branch was sometimes used to distinguish a programmable calculator from a computer.

The first handheld calculator was developed by Texas Instruments in 1967. It could add, multiply, subtract, and divide, and its output device was a paper tape.^[17][18]

1970s to mid-1980s

Old calculator LED display.

The electronic calculators of the mid-1960s were large and heavy desktop machines due to their use of hundreds of transistors on several circuit boards with a large power consumption that required an AC power supply. There were great efforts to put the logic required for a calculator into fewer and fewer integrated circuits (chips) and calculator electronics was one of the leading edges of semiconductor development. U.S. semiconductor manufacturers led the world in Large Scale Integration (LSI) semiconductor development, squeezing more and more functions into individual integrated circuits. This led to alliances between Japanese calculator manufacturers and U.S. semiconductor companies: Canon Inc. with Texas Instruments, Hayakawa Electric (later known as Sharp Corporation) with North-American Rockwell Microelectronics, Busicom with Mostek and Intel, and General Instrument with Sanyo.

Pocket calculators

Adler 81S pocket calculator with vacuum fluorescent display from the mid 1970's.

By 1970 a calculator could be made using just a few chips of low power consumption, allowing portable models powered from rechargeable batteries. The first portable calculators appeared in Japan in 1970, and were soon marketed around the world. These included the Sanyo ICC-0081 "Mini Calculator", the Canon Pocketronic, and the Sharp QT-8B "micro Compet". The Canon Pocketronic was a development of the "Cal-Tech" project which had been started at Texas Instruments in 1965 as a research project to produce a portable calculator. The Pocketronic has no traditional display; numerical output is on thermal paper tape. As a result of the "Cal-Tech" project Texas instruments was granted master patents on portable calculators.

Sharp put in great efforts in size and power reduction and introduced in January 1971 the Sharp EL-8, also marketed as the Facit 1111, which was close to being a pocket calculator. It weighed about one pound, had a vacuum fluorescent display, rechargeable NiCad batteries, and initially sold for $395.

However, the efforts in integrated circuit development culminated in the introduction in early 1971 of the first "calculator on a chip", the MK6010 by Mostek,^[19] followed by Texas Instruments later in the year. Although these early hand-held calculators were very expensive, these advances in electronics, together with developments in display technology (such as the vacuum fluorescent display, LED, and LCD), lead within a few years to the cheap pocket calculator available to all.

The first truly pocket-sized electronic calculator was the Busicom LE-120A "HANDY", which was marketed early in 1971. Made in Japan, this was also the first calculator to use an LED display, the first hand-held calculator to use a single integrated circuit (then proclaimed as a "calculator on a chip"), the Mostek MK6010, and the first electronic calculator to run off replaceable batteries. Using four AA-size cells the LE-120A measures 4.9x2.8x0.9 in (124x72x24 mm).

The first American-made pocket-sized calculator, the Bowmar 901B (popularly referred to as The Bowmar Brain), measuring 5.2×3.0×1.5 in (131×77×37 mm), came out in the fall of 1971, with four functions and an eight-digit red LED display, for $240, while in August 1972 the four-function Sinclair Executive became the first slimline pocket calculator measuring 5.4×2.2×0.35 in (138×56×9 mm) and weighing 2.5 oz (70g). It retailed for around $150 (GB£79). By the end of the decade, similar calculators were priced less than $10 (GB£5).

The first Soviet-made pocket-sized calculator, the "Elektronika B3-04" was developed by the end of 1973 and sold at the beginning of 1974.

One of the first low-cost calculators was the Sinclair Cambridge, launched in August 1973. It retailed for £29.95, or some £5 less in kit form. The Sinclair calculators were successful because they were far cheaper than the competition; however, their design was flawed and their accuracy in some functions was questionable. The scientific programmable models were particularly poor in this respect, with the programmability coming at a heavy price in transcendental accuracy.

Meanwhile Hewlett Packard (HP) had been developing its own pocket calculator. Launched in early 1972 it was unlike the other basic four-function pocket calculators then available in that it was the first pocket calculator with scientific functions that could replace a slide rule. The $395 HP-35, along with all later HP engineering calculators, used reverse Polish notation (RPN), also called postfix notation. A calculation like "8 plus 5" is, using RPN, performed by pressing "8", "Enter↑", "5", and "+"; instead of the algebraic infix notation: "8", "+", "5", "=").

The first Soviet scientific pocket-sized calculator the "B3-18" was completed by the end of 1975.

In 1973, Texas Instruments(TI) introduced the SR-10, (SR signifying slide rule) an algebraic entry pocket calculator for $150. It was followed the next year by the SR-50 which added log and trig functions to compete with the HP-35, and in 1977 the mass-marketed TI-30 line which is still produced.

The first programmable pocket calculator was the HP-65, in 1974; it had a capacity of 100 instructions, and could store and retrieve programs with a built-in magnetic card reader. A year later the HP-25C introduced continuous memory, i.e. programs and data were retained in CMOS memory during power-off. In 1979, HP released the first alphanumeric, programmable, expandable calculator, the HP-41C. It could be expanded with RAM (memory) and ROM (software) modules, as well as peripherals like bar code readers, microcassette and floppy disk drives, paper-roll thermal printers, and miscellaneous communication interfaces (RS-232, HP-IL, HP-IB).

The first Soviet programmable calculator Elektronika "B3-21" was developed by the end of 1977 and sold at the beginning of 1978. The successor of B3-21, the Elektronika B3-34 wasn't backward compatible with B3-21, even if it kept the reverse Polish notation (RPN). Thus B3-34 defined a new command set, which later was used in all programmable soviet calculators. There are hundreds of developed programs for science, business and even games for these machines. The Elektronika MK-52 calculator (using the extended B3-34 command set, and featuring internal EEPROM memory for storing programs and external interface for EEPROM cards and other periphery) was used in soviet spacecraft program (for Soyuz TM-7 flight) as a backup of the board computer.

Mechanical calculators continued to be sold, though in rapidly decreasing numbers, into the early 1970s, with many of the manufacturers closing down or being taken over. Comptometer type calculators were often retained for much longer to be used for adding and listing duties, especially in accounting, since a trained and skilled operator could enter all the digits of a number in one movement of the hands on a Comptometer quicker than was possible serially with a 10-key electronic calculator. The spread of the computer rather than the simple electronic calculator put an end to the Comptometer. Also, by the end of the 1970s, the slide rule had become obsolete.

Technical improvements

Through the 1970s the hand-held electronic calculator underwent rapid development. The red LED and blue/green vacuum fluorescent displays consumed a lot of power and the calculators either had a short battery life (often measured in hours, so rechargeable nickel-cadmium batteries were common) or were large so that they could take larger, higher capacity batteries. In the early 1970s Liquid crystal displays (LCDs) were in their infancy and there was a great deal of concern that they only had a short operating lifetime. Busicom introduced the Busicom LE-120A "HANDY" calculator, the first pocket-sized calculator and the first with an LED display, and announced the Busicom LC with LCD display. However, there were problems with this display and the calculator never went on sale. The first successful calculators with LCDs were manufactured by Rockwell International and sold from 1972 by other companies under such names as: Dataking LC-800, Harden DT/12, Ibico 086, Lloyds 40, Lloyds 100, Prismatic 500 (aka P500), Rapid Data Rapidman 1208LC. The LCDs were an early form with the numbers appearing as silver against a dark background. To present a high-contrast display these models illuminated the LCD using a filament lamp and solid plastic light guide, which negated the low power consumption of the display. These models appear to have been sold only for a year or two.

A more successful series of calculators using the reflective LCD display was launched in 1972 by Sharp Inc with the Sharp EL-805, which was a slim pocket calculator. This, and another few similar models, used Sharp's "COS" (Crystal on Substrate) technology. This used a glass-like circuit board which was also an integral part of the LCD. In operation the user looked through this "circuit board" at the numbers being displayed. The "COS" technology may have been too expensive since it was only used in a few models before Sharp reverted to conventional circuit boards, though all the models with the reflective LCD displays are often referred to as "COS".

In the mid-1970s the first calculators appeared with the now "normal" LCDs with dark numerals against a grey background, though the early ones often had a yellow filter over them to cut out damaging UV rays. The big advantage of the LCD is that it is passive and reflects light, which requires much less power than generating light. This led the way to the first credit-card-sized calculators, such as the Casio Mini Card LC-78 of 1978, which could run for months of normal use on a couple of button cells.

There were also improvements to the electronics inside the calculators. All of the logic functions of a calculator had been squeezed into the first "Calculator on a chip" integrated circuits in 1971, but this was leading edge technology of the time and yields were low and costs were high. Many calculators continued to use two or more integrated circuits (ICs), especially the scientific and the programmable ones, into the late 1970s.

The power consumption of the integrated circuits was also reduced, especially with the introduction of CMOS technology. Appearing in the Sharp "EL-801" in 1972, the transistors in the logic cells of CMOS ICs only used any apreciable power when they changed state. The LED and VFD displays had often required additional driver transistors or ICs, whereas the LCD displays were more amenable to being driven directly by the calculator IC itself.

With this low power consumption came the possibility of using solar cells as the power source, realised around 1978 by such calculators as the Royal Solar 1, Sharp EL-8026, and Teal Photon.

A pocket calculator for everyone

At the beginning of the 1970s hand-held electronic calculators were very expensive, costing two or three weeks' wages, and so were a luxury item. The high price was due to their construction requiring many mechanical and electronic components which were expensive to produce, and production runs were not very large. Many companies saw that there were good profits to be made in the calculator business with the margin on these high prices. However, the cost of calculators fell as components and their production techniques improved, and the effect of economies of scale were felt.

By 1976 the cost of the cheapest 4-function pocket calculator had dropped to a few dollars, about one twentieth of the cost five years earlier. The consequences of this were that the pocket calculator was affordable, and that it was now difficult for the manufacturers to make a profit out of calculators, leading to many companies dropping out of the business or closing down altogether. The companies that survived making calculators tended to be those with high outputs of higher quality calculators, or producing high-specification scientific and programmable calculators.

Mid-1980s to present

The first calculator capable of symbolic computation was the HP-28, released in 1987. It was able to, for example, solve quadratic equations symbolically. The first graphing calculator was the Casio fx7000G released in 1985.

The two leading manufacturers, HP and TI, released increasingly feature-laden calculators during the 1980s and 1990s. At the turn of the millennium, the line between a graphing calculator and a handheld computer was not always clear, as some very advanced calculators such as the TI-89, the Voyage 200 and HP-49G could differentiate and integrate functions, solve differential equations, run word processing and PIM software, and connect by wire or IR to other calculators/computers.

The CASIO CM-602 Mini Electronic Calculator provided basic functions in the 1970s

The HP 12c financial calculator is still produced. It was introduced in 1981 and is still being made with few changes. The HP 12c featured the reverse Polish notation mode of data entry. In 2003 several new models were released, including an improved version of the HP 12c, the "HP 12c platinum edition" which added more memory, more built-in functions, and the addition of the algebraic mode of data entry.

Online calculators are programs designed to work just like a normal calculator does. Usually the keyboard (or the mouse clicking a virtual numpad) is used, but other means of input (e.g. slide bars) are possible.

Thanks to the Internet, many new types of calculators are possible for calculations that would otherwise be much more difficult or impossible, such as for real time currency exchange rates, loan rates and statistics.

mp4 camcorder

rifle telescope

plastic pp

side camera

stand camera

rechargeable camera

mini binocular

xerox dc

gem loupe

coin telescope

currency discriminator

medical microscope

plate camera

reading lens

ophthalmic unit

hp q5949a

infared lens

night vison

water-resistant camera

cc camera

flexible camera

folding telescope

wirless camera

roland 540

helmet lens

xerox 3117

pelco cameras

iridology camera

TFT Camcorder

Webcam Lens

Look up bulletin board, notice board in Wiktionary, the free dictionary.

Well-used bulletin board on the Infinite Corridor at MIT, November 2004.

Cork, a common bulletin board material

A bulletin board (pinboard, pin board or notice board in British English) is a place where people can leave public messages, for example, to advertise things to buy or sell, announce events, or provide information. Bulletin boards are often made of a material such as cork to facilitate addition and removal of messages or it can be placed on the computer so people can leave and erase messages for other people to read and see.

Bulletin boards are particularly prevalent at universities. Many sport dozens, if not hundreds or thousands of public bulletin boards, used for everything from advertisements by extracurricular groups and local shops to official notices. Dormitory corridors, well-trafficked hallways, lobbies, and freestanding kiosks often have cork boards attached to facilitate the posting of notices. At some universities, lampposts, bollards, trees, and walls often become impromptu postering sites in areas where official boards are sparse in number.

toshiba 1710

Mini Lens

Chip Camera

Endoscope Camera

Plastic Magnifier

Binocular Lens

8X Monocular

10X Binocular

Promotional Magnifier

8X Binoculars

Plastic Binoculars

Highlighter Set

WLAN Camera

PVC Pockets

Office Suppliers

Cr Lens

Plastic Telescope

Tube Lens

7X Binoculars

4X Binoculars

Projector Optical

Pencil Accessories

Laboratory Microscopes

Rubber Binoculars

artcut 2005

gel sticky

epson 7800

lcd projetor

ibm 9068

day/night cameras

A single, large sized binder clip.

A binder clip, or a banker's clip, is a simple device for binding a few to many sheets of paper. It leaves the paper intact and can be removed quickly and easily unlike the staple. The term bulldog clip is used in the United Kingdom to describe both this invention and an older device with the same function, which is stronger and has rigid rather than folding handles.

Characteristics and methods of use

The handles can be folded down once the clip has been attached, and can also be removed for permanent binding.

An assortment of binder clips, with an AA battery for scale.

A binder clip is a strip of stainless sheet steel bent into the shape of an isosceles triangle with loops at the apex. Tension along the base of the triangle forces the two sides closed, and the loops prevent the sharp steel edges from cutting into the paper. The loops also serve to hold two pieces of stiff wire, which serve as handles and allow the clip to be opened. The two slots cut in each loop are shaped so that the wire handles can be folded down once the clip has been attached, and the spring force of the wire holds them down on the surface of the paper. This holds the clip relatively flat, for easier stacking of paper. One handle can also be folded down while the other remains ups to allow the stack of papers to be hung up. The handles can also be removed altogether by squeezing them sideways and pulling them out, allowing for more permanent binding. As compared to a paper clip, the binder clip is able to bind sheets of paper more securely, and is also resistant to rust^[1].

There are several sizes of binder clips, ranging from a base size of 9 millimetres (0.35 in) to 50 mm (1.97 in). The sheet steel portion is customarily painted black, with the handles chrome plated, but a variety of decorative color schemes are also available. The sheet steel portion is usually made of stainless steel, but can also be finished in nickel, silver or gold^[1].

Uses

The binder clip is commonly used in the modern office. It can hold a few to many sheets of paper, and is usually used in place of the paper clip for large volumes of paper. It can also be used to hold pieces of quilt together and to balance machinery or as a bookmark.^[1].

History

The binder clip was invented by Washingtonian Louis E. Baltzley in 1911. At that time, the method of binding sheets of paper together was to punch holes in them and sew them together, making it tedious to remove a single sheet of paper. Baltzley invented the binder clip to help his father, Edwin Baltzley, a writer and inventor, hold his manuscripts together easily. While the original design has since been changed five times, the basic mechanism has remained the same^[2].

Screw Camera

Magnetic Lens

TV Magnifier

Image Lens

ENt Microscope

oem products.

operating microscope

Ophthalmic Microscope

Motor Zoom

French Curve

Industrial Microscope

Yarn Supply

Telescope Binoculars

Gift Binoculars

used photocopy

toner import

kyocera tk17

Sporting Scope

LCD DC

Wall Camera

Optical Polarizer

LCD Polarizer

pen factory

HP Compatable

Punch Hole

MMC 32MB

Printer Brand

Stationery Supply

Parking Cameras

PD Meter

An address book or a name and address book (NAB) is a book or a database used for storing entries called contacts. Each contact entry usually consists of a few standard fields (for example: first name, last name, company name, address, telephone number, e-mail address, fax number, mobile phone number). Most such systems store the details in alphabetical order of people's names, although in paper-based address books entries can easily end up out of order as the owner inserts details of more individuals or as people move. Many address books use small ring binders that allow adding, removing and shuffling of pages to make room.

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Little black book

A related term that has entered the popular lexicon is little black book (or simply black book). Such books are used as dating guides, listing people who the owner has dated in the past or hopes to in the future. More explicit variations are guides for sexual encounters. It is unclear how prevalent this is in practice or when it originated, though such books have been mentioned in many pieces of popular culture. For example, the 1953 film version of Kiss Me, Kate features a musical scene in which Howard Keel's character laments the loss of the social life he enjoyed before marriage, naming numerous female romantic encounters whilst perusing a miniature black book. More recently, the mid-2000s Guinness Brewmasters advertising campaign features the "little black book" as an invention of one of the brewmasters.

Software address book

Address books can also appear as software designed for this purpose, such as the "Address Book" application included with Apple Computer's Mac OS X. Simple address books have been incorporated into e-mail software for many years, though more advanced versions have emerged in the 1990s and beyond; and also in mobile phones.

A personal information manager (PIM) integrates an address book, calendar, task list, and sometimes other features.

Entries can be imported and exported from the software in order to transfer them between programs or computers. The common file formats for these operations are:

• LDIF (*.ldif, *.ldi)
• Tab delimited (*.tab, *.txt)
• Comma separated (*.csv)
• vCard (*.vcf)

Individual entries are frequently transferred as vCards (*.vcf), which are roughly comparable to physical business cards. And some software applications like Lotus Notes and Open Contacts can handle a vCard file containing multiple vCard records.

Glitter Pencils

bone pen

conductive glue

animal erasers

Children Stationery

cartoon bags

bubble sticker

Diamond Stickers

zipper binder

Dustless Chalk

fiber-glass tape

KERATIN GLUE

Jewel Sticker

jumbo pens

Liquid Glue

looseleaf notebook

chinese pens

home sticker

chinese stationery

extensions glue

desk file

copper drawing

equatorial telescope

edger lens

hot camera

dome magnifier

chinese camera

dual cameras

collimator lens

ip66 camera

Thats just the inside view of a puplic transportation unit. Which provides actually a lot of work: 1 Busdriver, 1 Ticketseller, 2-3 controller = up to 5 people... is amazing isn't it Ah yeah and by the way is air conditioned and cost about 1/5 of a dollar...
And i nearly hit the roof and i am 172 short

Hey,

just a few things i wanted to add...

I mean everybody knows germans or at least heard of them... And all the people which have allready been to Viet Nam know about Motorbike taxidriver, so it just happend a couple days ago that a group germans  've been standing in front of a bar, as on the sudden one of this group pushed a taxidriver in the back (don't ask me why). There are a few things you shouldn't do and thats for sure one of those. To put it in a nutshell: Around 30 Taxidriver armed with sticks and helmets beat the germans up until they needed to go for hospital...So be aware of what you are doing, especially in foreign countrys.

Second one i wanted to add is that some of these Vietnamese people can even see the human behind the appearance. So there is on eldery sellswoman couple doors away from my living place which is just amiable, waving and smiling if i pass by. Not trying to sell anything, or maybe is just a new strategy to be nice until the persons comes up and buys something

 And third i am still disappointed with my first fieldtrip, keeps holding me busy to redo everything and i can't get rid of the feeling that the alternative plan delivers to less data to come up with good results, but the best plan is just not working here, like many other things too. So you need to be aware that energy drops out every now and than or internet is just not working for days... so but you can ind always a place where is w-lan access. Nearly every Hotel has one and mostly they are not locked or just secured with something like 12345abcde

Thats about it... i take a swim in the ocean know and will do some of my twirling practices...

in other usage