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Base 8
Octal (base 8) is a numeral system with eight as the base. In the decimal system, each place is a power of ten. For example: : \mathbf_ = \mathbf \times 10^1 + \mathbf \times 10^0 In the octal system, each place is a power of eight. For example: : \mathbf_8 = \mathbf \times 8^2 + \mathbf \times 8^1 + \mathbf \times 8^0 By performing the calculation above in the familiar decimal system, we see why 112 in octal is equal to 64+8+2=74 in decimal. Octal numerals can be easily converted from binary representations (similar to a quaternary numeral system) by grouping consecutive binary digits into groups of three (starting from the right, for integers). For example, the binary representation for decimal 74 is 1001010. Two zeroes can be added at the left: , corresponding to the octal digits , yielding the octal representation 112. Usage In China The eight bagua or trigrams of the I Ching correspond to octal digits: * 0 = ☷, 1 = ☳, 2 = ☵, 3 = ☱, * 4 = ☶, 5 = � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Numeral System
A numeral system is a writing system for expressing numbers; that is, a mathematical notation for representing numbers of a given set, using digits or other symbols in a consistent manner. The same sequence of symbols may represent different numbers in different numeral systems. For example, "11" represents the number ''eleven'' in the decimal or base-10 numeral system (today, the most common system globally), the number ''three'' in the binary or base-2 numeral system (used in modern computers), and the number ''two'' in the unary numeral system (used in tallying scores). The number the numeral represents is called its ''value''. Additionally, not all number systems can represent the same set of numbers; for example, Roman, Greek, and Egyptian numerals don't have a representation of the number zero. Ideally, a numeral system will: *Represent a useful set of numbers (e.g. all integers, or rational numbers) *Give every number represented a unique representation (or a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
An Essay Towards A Real Character, And A Philosophical Language
''An Essay Towards a Real Character, and a Philosophical Language'' (London, 1668) is the best-remembered of the numerous works of John Wilkins, in which he expounds a new universal language, meant primarily to facilitate international communication among scholars, but envisioned for use by diplomats, travelers, and merchants as well. Unlike many universal language schemes of the period, it was meant merely as an auxiliary to—not a replacement of—existing natural languages. Background One of the aims of the ''Essay'' was to provide a replacement for the Latin language, which had been the international language of scholars in Western Europe by then for 1000 years. Comenius and others interested in international languages had criticisms of the arbitrary features of Latin that made it harder to learn, and Wilkins also made such points. A scheme for a ''lingua franca'' based on numerical values had been published by John Pell (1630); and in his 1640 work ''Mercury or the Secret ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Mainframe
IBM mainframes are large computer systems produced by IBM since 1952. During the 1960s and 1970s, IBM dominated the computer market with the 7000 series and the later System/360, followed by the System/370. Current mainframe computers in IBM's line of business computers are developments of the basic design of the System/360. First and second generation From 1952 into the late 1960s, IBM manufactured and marketed several large computer models, known as the IBM 700/7000 series. The first-generation 700s were based on vacuum tubes, while the later, second-generation 7000s used transistors. These machines established IBM's dominance in electronic data processing ("EDP"). IBM had two model categories: one (701, 704, 709, 7030, 7090, 7094, 7040, 7044) for engineering and scientific use, and one (702, 705, 705-II, 705-III, 7080, 7070, 7072, 7074, 7010) for commercial or data processing use. The two categories, scientific and commercial, generally used common peripherals but had co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ICT 1900 Series
ICT 1900 was a family of mainframe computers released by International Computers and Tabulators (ICT) and later International Computers Limited (ICL) during the 1960s and 1970s. The 1900 series was notable for being one of the few non-American competitors to the IBM System/360, enjoying significant success in the European and British Commonwealth markets. Origins In early 1963, ICT was engaged in negotiations to buy the computer business of Ferranti. In order to sweeten the deal, Ferranti demonstrated to ICT the Ferranti-Packard 6000 (FP6000) machine, which had been developed by its Canadian subsidiary Ferranti-Packard, to a design known as Harriac that had been initiated in Ferranti by Harry Johnson and fleshed out by Stanley Gill and John Iliffe. The FP6000 was an advanced design, notably including hardware support for multiprogramming. ICT considered using the FP6000 as their medium-sized processor in the 1965–1968 timeframe, replacing the ICT 1302. Anoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-8
The PDP-8 is a family of 12-bit minicomputers that was produced by Digital Equipment Corporation (DEC). It was the first commercially successful minicomputer, with over 50,000 units sold during the model's lifetime. Its basic design follows the pioneering LINC but has a smaller instruction set, which is an expanded version of the PDP-5 instruction set. Similar machines from DEC are the PDP-12 which is a modernized version of the PDP-8 and LINC concepts, and the PDP-14 industrial controller system. Overview The earliest PDP-8 model, informally known as a "Straight-8", was introduced on 22 March 1965 priced at $18,500 (). It uses diode–transistor logic packaged on flip chip cards in a machine about the size of a small household refrigerator. It was the first computer to be sold for under $20,000, making it the best-selling computer in history at that time. The Straight-8 was supplanted in 1966 by the PDP-8/S, which was available in desktop and rack-mount models. Using a on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNIVAC 1050
The UNIVAC 1050 was a variable word-length (computer hardware), variable word-length (one to 16 characters) decimal and binary computer. It was initially announced in May 1962 as an off-line input-output processor for larger UNIVAC systems. Instruction set, Instructions were fixed length (30 bits – five characters), consisting of a five-bit "opcode, op code", a three-bit index register specifier, one reserved bit, a 15-bit address, and a six-bit "detail field" whose function varies with each instruction. The memory was up to 32K of six-bit characters. The first 256 memory positions were group into 64 fields of 4 characters each, called "tetrads", it is possible to address any of these positions either by tetrad or by individual character. These Tetrads were used to implement the following: * 2 x Arithmetic Registers (each 16 characters wide) * 7 x Index Registers (each 3 characters wide) * Multiplier and Quotient (each 4 characters wide) * 6 x I/O Channels Like the IBM 1401 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
English Units
English units were the units of measurement used in England up to 1826 (when they were replaced by Imperial units), which evolved as a combination of the Anglo-Saxons, Anglo-Saxon and Ancient Roman units of measurement, Roman systems of units. Various standards have applied to English units at different times, in different places, and for different applications. Use of the term "English units" can be ambiguous, as, in addition to the meaning used in this article, it is sometimes used to refer to the units of the descendant Imperial system as well to those of the descendant system of United States customary units. The two main sets of English units were the Winchester measure, Winchester Units, used from 1495 to 1587, as affirmed by Henry VII of England, King Henry VII, and the Exchequer Standards, in use from 1588 to 1825, as defined by Queen Elizabeth I. In England (and the British Empire), English units were replaced by Imperial units in 1824 (effective as of 1 January 1826) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metric System
The metric system is a system of measurement that standardization, standardizes a set of base units and a nomenclature for describing relatively large and small quantities via decimal-based multiplicative unit prefixes. Though the rules governing the metric system have changed over time, the modern definition, the International System of Units (SI), defines the metric prefixes and seven base units: metre (m), kilogram (kg), second (s), ampere (A), kelvin (K), Mole (unit), mole (mol), and candela (cd). An SI derived unit is a named combination of base units such as hertz (cycles per second), Newton (unit), newton (kg⋅m/s2), and tesla (unit), tesla (1 kg⋅s−2⋅A−1) and in the case of Celsius a shifted scale from Kelvin. Certain units have been Non-SI units mentioned in the SI#Units officially accepted for use with the SI, officially accepted for use with the SI. Some of these are decimalised, like the litre and electronvolt, and are considered "metric". Others, like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Anderson Of Hermiston
James Anderson Fellow of the Royal Society of Edinburgh, FRSE FSAScot (1739 – 15 October 1808) was a Scottish agriculturist, journalist and economist. A member of the Edinburgh Philosophical Society, Anderson was a prominent figure in the Scottish Enlightenment. He invented the Scotch plough. As a writer he adopted the nom de plume of Agricola. Life Anderson was born at Hermiston, Midlothian the son of a farmerGrant's Old and New Edinburgh vol.6 p.335 and while still young attended lectures on chemistry by William Cullen, at the University of Edinburgh. At the age of 15, after the death of his father, he took over the working of the ancestral farm. In 1768 he moved to Aberdeenshire to manage the farm of Monkshill on land owned by Mr. Udny of Udny Green, Udny under a long lease granted to him for the purpose of demonstrating the benefits of Agricultural improvement, improved agriculture. Economic theorist In 1777 Anderson published ''An Enquiry into the Nature of the Corn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hugh Jones (reverend)
The Reverend Hugh Jones (1691–1760) is the most famous and accomplished of a sometimes confusing array of Anglican clergymen of the same name from the American colonies of Virginia and Maryland. Jones is best known for his authorship of The Present State of Virginia, and a short view of Maryland and North Carolina' (London, 1724). For several years he taught mathematics at The College of William and Mary, in Williamsburg, Virginia, wherJones Hallis named for him. Birth and education He appears to have been born in Herefordshire, England, just east of Wales, in the parish of Little Dewchurch. Alumni records at Oxford University list his matriculation to Jesus College, Oxford, Jesus College in March 1708, age 17, placing his birth around 1691. He received the B.A. in 1712, according to these records, and the M.A. in 1716. In a deposition given at age 49 (1740), he said "That he learnt Arithmetick at School, studied Geometry, Geography and Astronomy in the University of Oxford;" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Gentleman's Magazine
''The Gentleman's Magazine'' was a monthly magazine founded in London, England, by Edward Cave in January 1731. It ran uninterrupted for almost 200 years, until 1907, ceasing publication altogether in 1922. It was the first to use the term ''magazine'' (from the French language, French ''magazine'', meaning "storehouse") for a periodical. Samuel Johnson's first regular employment as a writer was with ''The Gentleman's Magazine''. History The original complete title was ''The Gentleman's Magazine: or, Trader's monthly intelligencer''. Cave's innovation was to create a monthly digest of news and commentary on any topic the educated public might be interested in, from commodity prices to Latin poetry. It carried original content from a stable of regular contributors, as well as extensive quotations and extracts from other periodicals and books. Cave, who edited ''The Gentleman's Magazine'' under the pen name "Sylvanus Urban", was the first to use the term ''magazine'' (meaning "st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Art Of Computer Programming
''The Art of Computer Programming'' (''TAOCP'') is a comprehensive multi-volume monograph written by the computer scientist Donald Knuth presenting programming algorithms and their analysis. it consists of published volumes 1, 2, 3, 4A, and 4B, with more expected to be released in the future. The Volumes 1–5 are intended to represent the central core of computer programming for sequential machines; the subjects of Volumes 6 and 7 are important but more specialized. When Knuth began the project in 1962, he originally conceived of it as a single book with twelve chapters. The first three volumes of what was then expected to be a seven-volume set were published in 1968, 1969, and 1973. Work began in earnest on Volume 4 in 1973, but was suspended in 1977 for work on typesetting prompted by the second edition of Volume 2. Writing of the final copy of Volume 4A began in longhand in 2001, and the first online pre-fascicle, 2A, appeared later in 2001. The first published installment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
