iPhone 6

The iPhone 6 and iPhone6 Plus are smartphones designed and marketed by Apple Inc. The devices are part of the iPhone series and were unveiled on September 9, 2014, and released on September 19, 2014. The iPhone 6 and iPhone 6 Plus jointly serve as successors to the iPhone 5C and iPhone 5S.

The iPhone 6 and iPhone 6 Plus include a number of changes over their predecessor, including models with larger 4.7 and 5.5 inches (120 and 140 mm) displays, a faster processor, upgraded cameras, improved LTE and Wi-Fi connectivity and support for anear field communications-based mobile payments offering.

Pre-orders of the iPhone 6 and iPhone 6 Plus exceeded four million within its first 24 hours of availability—an Apple record.More than ten million iPhone 6 and iPhone 6 Plus devices were sold in the first three days, another Apple record.

On September 9, 2015, the 128 GB version of both the iPhone 6 and iPhone 6 Plus was discontinued along with the gold version of both phones, but the 16 GB and 64 GB versions of the iPhone 6 and iPhone 6 Plus in silver and space gray remain available for sale at a reduced price due to the release of the iPhone 6S and iPhone 6S Plus flagship devices

iPhone 4S .

The iPhone 5 is often a smartphone that was designed and marketed by Apple Inc. It is the sixth generation of the iPhone , succeeding theiPhone 4S and preceding the iPhone 5S and iPhone 5C . Formally unveiled as part of a press event on September 12, 2012, it was released in September 21, 2012. [12] It was the first iPhone to be completely developed under the guidance of Tim Cook .
The iPhone 5 featured major design changes in comparison to its predecessor. These included an aluminum-based body which was thinner and lighter than previous models, a taller screen which has a nearly 16: 9 aspect ratio , the Apple A6 system-on-chip , LTE support, and Lightning , a new compact dock connector which replaces the 30-pin design used by previous iPhone models. This was the second Apple phone to include its new Sony made 8MP Digicam, first introduced on the iPhone 4S .
Apple began taking pre-orders on September 14, 2012, [2] and over two million were received within 24 hours. [6] Initial demand for the iPhone 5 exceeded the supply available at launch on September 21, 2012, and was described by Apple while "extraordinary", with pre-orders having sold twenty times faster than its predecessors. While reception to the iPhone 5 was generally positive, consumers and reviewers noted hardware issues, such as an unintended purple hue in photos taken, and the phone's coating being prone to chipping. Reception was also mixed over Apple's decision to switch completely to another dock connector design, as the change affected iPhone 5's compatibility with accessories that were otherwise compatible with previous iterations of the line.
The iPhone 5 was officially discontinued by Apple on September 10, 2013 with the announcement of its successors, the iPhone 5S and the iPhone 5C . [13] The iPhone 5 contains the shortest lifespan of any iPhone ever produced with only twelve months in production.

10. Sony Xperia Z5 Premium

The world's first 4K screen within a phone - with some amazing bits bolted on too
OS: Android 5. 1 | Screen size: 5. 5-inch | Resolution: 2160 x 3840 | RAM: 3GB | Storage: 32GB | Battery: 3, 430mAh | Rear camera: 23MP | Front camera: 5. 1MP
Look, we know it's got a 4K tv screen. And yes, we know that sounds a bit mental. But trust us when we say that it's not as ludicrous as it sounds.
It's a brilliant display - there's nothing more pin-sharp on the market at 806ppi density. We're not convinced you'll be able to SEE those extra pixels, and they're not turned on at all times, but it's there.
What makes this phone great is the fact it's the phablet version of the Xperia Z5, which means it has a great camera, is waterproof and allows you to hear all your audio in beautiful upscaled sound quality.
Battery life could be better, but it's no worse than a lot on this list - if you would like try something different, the Z5 Premium could well be it.

Best phone 2015: the 10 best smartphones we've reviewed

Replace: If you're not taken by any of these phones in the list, we're kind enough to have given you a decent list of phones to also consider - with the Nexus 5X and iPhone 6 now in the list, we've given you even more choices below!
You're here for one thing: to find the best phone. Luckily for you, at TechRadar we look into every phone under the sun, putting the ones that matter through our rigorously vigorous testing process to create our indepth mobile phone reviews .
However, with so many to choose from, we've spent hours whittling them down to a top ten, taking into account the power, specs, design and just remember: value for money, although we'll always point you in the direction of the latest handsets.

Etymology

The primary known use of the word "computer" was in 1613 within a book called The Yong Mans Gleanings by English writer Richard Braithwait: "I haue read the truest computer of Times, along with the best Arithmetician that euer breathed, and he reduceth thy dayes in a short number. " It referred to a person who executed calculations, or computations. The word continued with the same meaning until center of the 20th century. From the end of the 19th century the word began to consider its more familiar meaning, a machine that carries out computations.

History

Pre-twentie

                                                                                                                                    Devices have been used to aid computation for many years, mostly using one-to-one correspondence with fingers . The earliest counting device was probably a variety of tally stick . Later record keeping aids throughout the Fertile Crescent bundled calculi (clay spheres, cones, etc. ) which represented numbers of items, probably livestock or grains, sealed in hollow unbaked clay containers. The use of counting rods is one case.                                                                                 

The abacus wasinitially 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 are invented. In a medieval European counting house , a checkered cloth could well be placed on a table, and markers moved around on it in line with certain rules, as an aid to calculating sums of dollars.

The Antikythera mechanism is regarded as the earliest mechanical analog "computer", according to Derek J. de Solla Price tag . [6] It was designed to calculate astronomical roles. It was discovered in 1901 in the Antikythera wreck off your Greek island of Antikythera , between Kythera and Crete , and possesses been dated to circa 100 BC. Devices of a a higher level complexity comparable to that of the Antikythera mechanism would not reappear until lots of years later.
Many mechanical aids to calculation and measurement ended up constructed for astronomical and navigation use. The planisphere was a star chart invented by Abū Rayhān al-Bīrūnī inside early 11th century. [7] The astrolabe was invented inside Hellenistic world in either the 1st or 2nd centuries BC and is also often attributed to Hipparchus . A combination of the planisphere along with dioptra , the astrolabe was effectively an analog computer capable of working out several kinds of problems in spherical astronomy . An astrolabe incorporating a hardware calendar computer[8] [9] and gear -wheels was conceived by Abi Bakr of Isfahan , Persia in 1235. [10] Abū Rayhān al-Bīrūnī invented the 1st mechanical geared lunisolar calendar astrolabe, [11] an early fixed-wired knowledge processing machine [12] which has a gear train and gear-wheels, [13] circa 1000 ADVERTISING.
The sector , a calculating instrument used for solving problems equal in shape, trigonometry, multiplication and division, and for various functions, such while squares and cube roots, was developed in the late sixteenth century and found application in gunnery, surveying and navigation.

Your slide rule was invented around 1620-1630, shortly after the publication of the very idea of the logarithm . It is a hand-operated analog computer pertaining to doing multiplication and division. As slide rule development progressed, included scales provided reciprocals, squares and square roots, cubes and dice roots, as well as transcendental functions such as logarithms along with exponentials, circular and hyperbolic trigonometry and other functions . Aviation is just about the few fields where slide rules are still in widespread employ, particularly for solving time-distance problems in light aircraft. To save space and for easier reading, these are typically circular devices rather than the basic linear slide rule shape. A popular example is the E6B .
Inside 1770s Pierre Jaquet-Droz , a Swiss watchmaker , built a mechanical doll (automata ) that can write holding a quill pen. By switching the number along with order of its internal wheels different letters, and hence distinct messages, could be produced. In effect, it could be mechanically "programmed" you just read instructions. Along with two other complex machines, the doll is a the Musée d'Art et d'Histoire of Neuchâtel , Switzerland , nevertheless operates. [14]
The tide-predicting machine invented by Sir William Thomson in 1872 was of great utility for you to navigation in shallow waters. It used a system of pulleys and wires to automatically calculate predicted tide levels for the set period at a particular location.
The differential analyser , a mechanical analog computer meant to solve differential equations by integration , used wheel-and-disc mechanisms to complete the integration. In 1876 Lord Kelvin had already mentioned the possible construction of such calculators, but he had been stymied with the limited output torque of the ball-and-disk integrators . [15] In a very differential analyzer, the output of one integrator drove the input in the next integrator, or a graphing output. The torque amplifier was the advance that allowed these machines to function. Starting in the 1920s, Vannevar Bush and others designed mechanical differential analyzers.

First general-purpose computing device

Charles Babbage , an English mechanical engineer and polymath , originated the thought of a programmable computer. Considered the "father of the computer ", [16] he conceptualized and invented the initial mechanical computer in the early 19th century. After taking care of his revolutionary difference engine , designed to aid in navigational data, in 1833 he realized that a much more general layout, anAnalytical Engine , was possible. The input of programs and data was being provided to the machine via punched cards , a method being used during the time to direct mechanical looms such as the Jacquard loom . Regarding output, the machine would have a printer, a curve plotter plus a bell. The machine would also be able to punch numbers onto cards being read in later. The Engine incorporated an arithmetic logic product , control flow in the form of conditional branching and also loops , and integrated memory , making it the first design for a general-purpose computer that might be described in modern terms as Turing-complete . [17] [18]
The device was about a century ahead of its time. All the parts for his machine must be made by hand - this was a major problem to get a device with thousands of parts. Eventually, the project was dissolved with all the decision of the British Government to cease funding. Babbage's failure to perform the analytical engine can be chiefly attributed to difficulties not merely of politics and financing, but also to his desire to produce an increasingly sophisticated computer and to move ahead faster than someone else could follow. Nevertheless, his son, Henry Babbage, completed a simplified version with the analytical engine's computing unit (the mill) in 1888. He gave a prosperous demonstration of its use in computing tables in 1906.

Later analog computers

Later analog computers

In the first half of the 20th century, many scientific computing requires were met by increasingly sophisticated analog computers , which used a principal mechanical or electrical model of the problem as a time frame for computation . However, these were not programmable and normally lacked the versatility and accuracy of modern digital computers. [19]
The 1st modern analog computer was a tide-predicting machine , invented by simply Sir William Thomson in 1872. The differential analyser , a mechanical analog computer meant to solve differential equations by integration using wheel-and-disc mechanisms, was conceptualized throughout 1876 by James Thomson , the brother of the additional famous Lord Kelvin. [15]
The art of mechanical analog computing reached its zenith while using differential analyzer , built by H. L. Hazen and Vannevar Bush at MIT starting in 1927. This built on the mechanical integrators of James Thomson plus the torque amplifiers invented by H. W. Nieman. A dozen of such devices were built before their obsolescence became obvious.
By the 1950s the success of digital electronic computers had spelled the final for most analog computing machines, but analog computers remain available in some specialized applications such as education 

Digital computer development

Digital computer development

The principle in the modern computer was first described by mathematician and revolutionary computer scientist Alan Turing , who set out the thought in his seminal 1936 paper, [20] On Computable Figures. Turing reformulated Kurt Gödel 's 1931 results on the boundaries of proof and computation, replacing Gödel's universal arithmetic-based formal language while using formal and simple hypothetical devices that became known as Turing models . He proved that some such machine would be competent at performing any conceivable mathematical computation if it were representable just as one algorithm . He went on to prove that there was no strategy to the Entscheidungsproblem by first showing that the halting problem pertaining to Turing machines is undecidable : in general, it is impossible to decide algorithmically whether a given Turing machine will ever before halt.
He also introduced the notion of a 'Universal Machine' (now generally known as a Universal Turing machine ), with the idea that a real machine could perform the tasks of any other machine, or basically, it is provably capable of computing anything that is computable by executing a plan stored on tape, allowing the machine to be programmable. Von Neumann acknowledged that the central concept of the modern computer was just for this paper. Turing machines are to this day a central. object of study in theory of computation . Except for the limitations imposed by his or her finite memory stores, modern computers are said to be Turing-complete , and that is to say, they have algorithm execution capability equivalent to your universal Turing machine .