1.
Units of information
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In computing and telecommunications, a unit of information is the capacity of some standard data storage system or communication channel, used to measure the capacities of other systems and channels. In information theory, units of information are used to measure the information contents or entropy of random variables. The most common units are the bit, the capacity of a system which can exist in two states, and the byte, which is equivalent to eight bits. Multiples of these units can be formed from these with the SI prefixes or the newer IEC binary prefixes, information capacity is a dimensionless quantity. In particular, if b is an integer, then the unit is the amount of information that can be stored in a system with N possible states. When b is 2, the unit is the shannon, equal to the content of one bit. A system with 8 possible states, for example, can store up to log28 =3 bits of information, other units that have been named include, Base b =3, the unit is called trit, and is equal to log23 bits. Base b =10, the unit is called decimal digit, hartley, ban, decit, or dit, Base b = e, the base of natural logarithms, the unit is called a nat, nit, or nepit, and is worth log2 e bits. Several conventional names are used for collections or groups of bits, a byte can represent 256 distinct values, such as the integers 0 to 255, or -128 to 127. The IEEE 1541-2002 standard specifies B as the symbol for byte, bytes, or multiples thereof, are almost always used to specify the sizes of computer files and the capacity of storage units. Most modern computers and peripheral devices are designed to manipulate data in whole bytes or groups of bytes, a group of four bits, or half a byte, is sometimes called a nibble or nybble. This unit is most often used in the context of number representations. Computers usually manipulate bits in groups of a size, conventionally called words. The number of bits in a word is defined by the size of the registers in the computers CPU. Some machine instructions and computer number formats use two words, or four words, computer memory caches usually operate on blocks of memory that consist of several consecutive words. These units are customarily called cache blocks, or, in CPU caches, virtual memory systems partition the computers main storage into even larger units, traditionally called pages. Terms for large quantities of bits can be formed using the range of SI prefixes for powers of 10, e. g. kilo =103 =1000, mega- =106 =1000000. These prefixes are often used for multiples of bytes, as in kilobyte, megabyte
2.
Byte
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The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of used to encode a single character of text in a computer. The size of the byte has historically been hardware dependent and no standards existed that mandated the size. The de-facto standard of eight bits is a convenient power of two permitting the values 0 through 255 for one byte, the international standard IEC 80000-13 codified this common meaning. Many types of applications use information representable in eight or fewer bits, the popularity of major commercial computing architectures has aided in the ubiquitous acceptance of the 8-bit size. The unit symbol for the byte was designated as the upper-case letter B by the IEC and IEEE in contrast to the bit, internationally, the unit octet, symbol o, explicitly denotes a sequence of eight bits, eliminating the ambiguity of the byte. It is a respelling of bite to avoid accidental mutation to bit. Early computers used a variety of four-bit binary coded decimal representations and these representations included alphanumeric characters and special graphical symbols. S. Government and universities during the 1960s, the prominence of the System/360 led to the ubiquitous adoption of the eight-bit storage size, while in detail the EBCDIC and ASCII encoding schemes are different. In the early 1960s, AT&T introduced digital telephony first on long-distance trunk lines and these used the eight-bit µ-law encoding. This large investment promised to reduce costs for eight-bit data. The development of microprocessors in the 1970s popularized this storage size. A four-bit quantity is called a nibble, also nybble. The term octet is used to specify a size of eight bits. It is used extensively in protocol definitions, historically, the term octad or octade was used to denote eight bits as well at least in Western Europe, however, this usage is no longer common. The exact origin of the term is unclear, but it can be found in British, Dutch, and German sources of the 1960s and 1970s, and throughout the documentation of Philips mainframe computers. The unit symbol for the byte is specified in IEC 80000-13, IEEE1541, in the International System of Quantities, B is the symbol of the bel, a unit of logarithmic power ratios named after Alexander Graham Bell, creating a conflict with the IEC specification. However, little danger of confusion exists, because the bel is a used unit
3.
Burroughs large systems
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In the 1970s, Burroughs Corporation was organized into three divisions with very different product line architectures for high-end, mid-range, and entry-level business computer systems. Each divisions product line grew from a different concept for how to optimize a computers instruction set for particular programming languages, the Burroughs Large Systems Group designed large mainframes using stack machine instruction sets with dense syllables and 48-bit data words. The first such design was the B5000 in 1961 and it was optimized for running ALGOL60 extremely well, using simple compilers. Subsequent major redesigns include the B6500/B6700 line and its successors, Burroughs Large Systems referred to all of these product lines together, in contrast to the COBOL-optimized Medium Systems or the flexible-architecture Small Systems. While the B5000 architecture is dead, it inspired the B6500, the third and largest line, the B8500, had no commercial success. In addition to a proprietary CMOS processor design Unisys also uses Intel Xeon processors and runs MCP, Microsoft Windows, the first member of the first series, the B5000, was designed beginning in 1961 by a team under the leadership of Robert Barton. It was a machine, well ahead of its time. It has been listed by the influential computing scientist John Mashey as one of the architectures that he admires the most, I always thought it was one of the most innovative examples of combined hardware/software design Ive seen, and far ahead of its time. The B5000 was succeeded by the B5500 and the B5700, while there was no successor to the B5700, the B5000 line heavily influenced the design of the B6500, and Burroughs ported the Master Control Program to that machine. All code automatically reentrant, programmers dont have to do anything more to have any code in any language spread across processors than to use just the two shown simple primitives, however, ESPOL had statements for each of the syllables in the architecture. This was a departure from the computer system design of the time, where a processor and its instruction set would be designed and then handed over to the software people. The B5000, B5500 and B5700 in Word Mode has two different addressing modes, depending on whether it is executing a program or a subroutine. For a main program, the T field of an Operand Call or Descriptor Call syllable is relative to the Program Reference Table. For subroutines, the type of addressing is dependent on the three bits of T and on the Mark Stack FlipFlop, as shown in B5x00 Relative Addressing. The B5000 was designed to exclusively support high-level languages and this was at a time when such languages were just coming to prominence with FORTRAN and then COBOL. FORTRAN and COBOL were considered weaker languages by some, when it comes to modern techniques, so a newer, mostly untried language was adopted. The ALGOL dialect chosen for the B5000 was Elliott ALGOL, first designed and implemented by C. A. R and this was a practical extension of ALGOL with IO instructions and powerful string processing instructions. Hoares famous Turing Award lecture was on this subject, thus the B5000 was based on a very powerful language
4.
NCR 315
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The NCR315 Data Processing System, released in January 1962 by NCR, was a second-generation computer. All printed circuit boards used resistor-transistor logic to create the various logic elements and it used 12-bit slab memory structure using core memory. The instructions could use a memory slab as either two 6-bit alphanumeric characters or as three 4-bit BCD characters, basic memory was 5000 slabs of handmade core memory, which was expandable to a maximum of 40,000 slabs in four refrigerator-size cabinets. Input/Output was by direct connections to each type of peripheral through a two-cable bundle with 1-inch-thick cables. Some devices like tape and the CRAM were daisy-chained to allow multiple drives to be connected. Later models in this include the 315-100 and the 315-RMC. The addressable unit of memory on the NCR315 series is a slab, short for syllable, consisting of 12 data bits and its size falls between a byte and a typical word. A slab may contain three digits or two characters of six bits each. A slab may contain a value from -99 to +999. A numeric value contains up to eight slabs, if the value is negative then the minus sign is the leftmost digit of this row. There are instructions to transform digits to or from alphanumeric characters and these commands use the accumulator, which has a maximum length of eight slabs. To accelerate the processing the accumulator works with an effective length, the NCR 315-100 was the second version of the original 315. It too had a 6 microsecond clock cycle, and from 10,000 to 40,000 slabs of memory, the 315-100 series console I/O incorporated a Teletype printer and keyboard in place of the original 315s IBM typewriter. The primary difference between the older NCR315 and the 315-100 was the inclusion of the Automatic Recovery Option, one of the problems with early generation of computers was that when a memory or program error occurred, the system would literally turn on a red light and halt. The normal recovery process was to copy all register and counter setting from the light panel. Usually the restart was from the beginning of the program. The upgrade to the 315 required the removal of approximate 1800 wire-wrapped connection on the backplane, the NCR 315-RMC, released in July 1965, was the first commercially available computer to employ thin film memory. This reduced the clock time to 800 nanoseconds
5.
Saturn Launch Vehicle Digital Computer
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The Saturn Launch Vehicle Digital Computer was a computer that provided the autopilot for the Saturn V rocket from launch to Earth orbit insertion. It was one of the components of the Instrument Unit, fitted to the S-IVB stage of the Saturn V. The LVDC also supported pre- and post-launch checkout of the Saturn hardware, the LVDC was used in conjunction with the Launch Vehicle Data Adaptor which performed signal conditioning to the sensor inputs to the computer from the launch vehicle. The LVDC was capable of executing 12190 instructions per second, for comparison, a 2012-era microprocessor can execute 4 instructions per cycle at 3 GHz, achieving 12 billion instructions per second, one million times faster. Its master clock ran at 2, memory was in the form of 13-bit syllables, each with a 14th parity bit. Instructions were one syllable in size, while data words were two syllables, main memory was random access magnetic core, in the form of 4, 096-word memory modules. Up to 8 modules provided a maximum of 32,768 words of memory, ultrasonic delay lines provided temporary storage. For reliability, the LVDC used triple-redundant logic and a voting system, the computer included three identical logic systems. Each logic system was split into a seven-stage pipeline, at each stage in the pipeline, a voting system would take a majority vote on the results, with the most popular result being passed on to the next stage in all pipelines. This meant that, for each of the seven stages, one module in any one of the three pipelines could fail, and the LVDC would still produce the correct results. The result was a reliability of 99. 6% over 250 hours of operation. With four memory modules, giving a capacity of 16,384 words. LVDC instruction words were split into a 4-bit opcode field and a 9-bit operand address field, memory was broken into 256-word sectors. 8 bits of the address specified a word within a sector, the eighteen possible LVDC instructions were, Unlike the Apollo Guidance Computer software, the software which ran on the LVDC seems to have vanished. The LVDC could also respond to a number of interrupts triggered by external events. For a Saturn IB these interrupts were, For a Saturn V these interrupts were, The LVDC was approximately 30 inches wide,12.5 inches high, and 10.5 inches deep and weighed 80 pounds. The chassis was made of magnesium-lithium alloy LA141, chosen for its stiffness, low weight. The chassis was divided into a 3 x 5 matrix of cells separated by walls through which coolant was circulated to remove the 138 Watts of power dissipated by the computer, slots in the cell walls held “pages” of electronics
6.
Nibble
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In computing, a nibble is a four-bit aggregation, or half an octet. It is also known as half-byte or tetrade, in a networking or telecommunication context, the nibble is often called a semi-octet, quadbit, or quartet. A nibble has sixteen possible values, a nibble can be represented by a single hexadecimal digit and called a hex digit. A full byte is represented by two digits, therefore, it is common to display a byte of information as two nibbles. Sometimes the set of all 256 byte values is represented as a 16×16 table, four-bit computer architectures use groups of four bits as their fundamental unit. Such architectures were used in microprocessors, pocket calculators and pocket computers. They continue to be used in some microcontrollers, the term nibble originates from its representing half a byte, with byte a homophone of the English word bite. The alternative spelling nybble reflects the spelling of byte, as noted in editorials of Kilobaud, another early recorded use of the term nybble was in 1977 within the consumer-banking technology group at Citibank. It created a pre-ISO8583 standard for transactional messages between cash machines and Citibanks data centers that used the basic informational unit NABBLE, the nibble is used to describe the amount of memory used to store a digit of a number stored in packed decimal format within an IBM mainframe. This technique is used to make faster and debugging easier. An 8-bit byte is split in half and each nibble is used to one decimal digit. The last nibble of the variable is reserved for the sign, thus a variable which can store up to nine digits would be packed into 5 bytes. Ease of debugging resulted from the numbers being readable in a hex dump where two hex numbers are used to represent the value of a byte, as 16×16 =28, for example, a five-byte BCD value of 31415926 5C represents a decimal value of +314159265. Historically, there are cases where nybble was used for a group of bits greater than 4, in the Apple II microcomputer line, much of the disk drive control and group-coded recording was implemented in software. Writing data to a disk was done by converting 256-byte pages into sets of 5-bit nibbles, moreover,1982 documentation for the Integrated Woz Machine refers consistently to an 8 bit nibble. The term byte once had the same ambiguity and meant a set of bits but not necessarily 8, hence the distinction of bytes and octets or of nibbles and quartets. Today, the terms byte and nibble almost always refer to 8-bit and 4-bit collections respectively and are rarely used to express any other sizes. The terms semi-nibble or nibblet have occasionally used to refer to half a nibble
7.
University of Iowa
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The University of Iowa is a flagship public research university in Iowa City, Iowa. Founded in 1847, Iowa is the oldest university in the state, the University of Iowa is organized into eleven colleges offering more than 200 areas of study and seven professional degrees. The university was the developer of the Master of Fine Arts degree. The Iowa alumni network exceeds 250,000, and the university budgeted revenues and expenses of $3.513 billion for 2015, the University of Iowas athletic teams, the Hawkeyes, compete in Division I of the NCAA and are members of the Big Ten Conference. The Hawkeyes field 24 varsity teams and have won 27 national championships, the University of Iowa was founded on February 25,1847, just 59 days after Iowa was admitted to the Union. The Constitution of the State of Iowa refers to a State University to be established in Iowa City without branches at any other place. The legal name of the university is the State University of Iowa, the first faculty offered instruction at the university beginning in March 1855 to students in the Old Mechanics Building, located where Seashore Hall is now. In September 1855, there were 124 students, of whom forty-one were women, the first president of the university was Amos Dean. The original campus consisted of the Iowa Old Capitol Building and the 10 acres of land on which it stood, until that date, it had been the third capitol of the Territory of Iowa. When the capitol of Iowa was moved to Des Moines in 1857, in 1855, Iowa became the first public university in the United States to admit men and women on an equal basis. The university offered its first doctorate in 1898, the university was the first state university to recognize the Gay, Lesbian, Bisexual, Transgender, and Allied Union. Also, the University of Iowa was the first Big Ten institution to promote an African American to the position of vice president. A shooting took place on campus on November 1,1991, in the summer of 2008, flood waters breached the Coralville Reservoir spillway, damaging more than 20 major campus buildings. Several weeks after the waters receded university officials placed a preliminary estimate on flood damage at $231.75 million. Later, the university estimated that repairs would cost about $743 million, later in 2008, UNESCO designated Iowa City the worlds third City of Literature, making it part of the UNESCO Creative Cities Network. Iowa legislators ultimately did not support the plan, in 2015, the Iowa Board of Regents selected Bruce Harreld, a business consultant with limited experience in academic administration, to succeed Sally Mason as president. In July 2016, the university took over the former AIB College of Business in Des Moines, Four bachelors programs are offered in Des Moines, an additional four masters-level programs are offered in Des Moines at the universitys site in the citys Western Gateway Park. The University of Iowas main campus, located in Iowa City, was designed by architect D. Elwood Cook
8.
Association for Computing Machinery
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The Association for Computing Machinery is an international learned society for computing. It was founded in 1947 and is the worlds largest scientific and it is a not-for-profit professional membership group. Its membership is more than 100,000 as of 2011 and its headquarters are in New York City. The ACM is an organization for academic and scholarly interests in computer science. Its motto is Advancing Computing as a Science & Profession, ACM is organized into over 171 local chapters and 37 Special Interest Groups, through which it conducts most of its activities. Additionally, there are over 500 college and university chapters, the first student chapter was founded in 1961 at the University of Louisiana at Lafayette. Many of the SIGs, such as SIGGRAPH, SIGPLAN, SIGCSE and SIGCOMM, sponsor regular conferences, the groups also publish a large number of specialized journals, magazines, and newsletters. ACM publishes over 50 journals including the prestigious Journal of the ACM, other publications of the ACM include, ACM XRDS, formerly Crossroads, was redesigned in 2010 and is the most popular student computing magazine in the US. ACM Interactions, an interdisciplinary HCI publication focused on the connections between experiences, people and technology, and the third largest ACM publication, ACM Computing Surveys ACM Computers in Entertainment A number of journals, specific to subfields of computer science, titled ACM Transactions. ACM has made almost all of its publications available to subscribers online at its Digital Library. Individual members additionally have access to Safari Books Online and Books24x7, ACM also offers insurance, online courses, and other services to its members. In 1997, ACM Press published Wizards and Their Wonders, Portraits in Computing, written by Christopher Morgan, the book is a collection of historic and current portrait photographs of figures from the computer industry. The ACM Portal is a service of the ACM. Its core are two sections, ACM Digital Library and the ACM Guide to Computing Literature. The ACM Digital Library is the collection of all articles published by the ACM in its articles, magazines. The Guide is a bibliography in computing with over one million entries, the ACM Digital Library contains a comprehensive archive starting in the 1950s of the organizations journals, magazines, newsletters and conference proceedings. Online services include a forum called Ubiquity and Tech News digest, there is an extensive underlying bibliographic database containing key works of all genres from all major publishers of computing literature. This secondary database is a rich discovery service known as The ACM Guide to Computing Literature, ACM adopted a hybrid Open Access publishing model in 2013
9.
International Standard Book Number
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The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces. Separating the parts of a 10-digit ISBN is also done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker
10.
Decimal digit
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A digit is a numeric symbol used in combinations to represent numbers in positional numeral systems. The name digit comes from the fact that the 10 digits of the hands correspond to the 10 symbols of the common base 10 numeral system, i. e. the decimal digits. In a given system, if the base is an integer. For example, the system has ten digits, whereas binary has two digits. In a basic system, a numeral is a sequence of digits. Each position in the sequence has a value, and each digit has a value. The value of the numeral is computed by multiplying each digit in the sequence by its place value, each digit in a number system represents an integer. For example, in decimal the digit 1 represents the one, and in the hexadecimal system. A positional number system must have a digit representing the integers from zero up to, but not including, thus in the positional decimal system, the numbers 0 to 9 can be expressed using their respective numerals 0 to 9 in the rightmost units position. The Hindu–Arabic numeral system uses a decimal separator, commonly a period in English, or a comma in other European languages, to denote the place or units place. Each successive place to the left of this has a value equal to the place value of the previous digit times the base. Similarly, each place to the right of the separator has a place value equal to the place value of the previous digit divided by the base. For example, in the numeral 10, the total value of the number is 1 ten,0 ones,3 tenths, and 4 hundredths. Note that the zero, which contributes no value to the number, the place value of any given digit in a numeral can be given by a simple calculation, which in itself is a compliment to the logic behind numeral systems. And to the right, the digit is multiplied by the base raised by a negative n, for example, in the number 10. This system was established by the 7th century in India, but was not yet in its modern form because the use of the digit zero had not yet widely accepted. Instead of a zero, a dot was left in the numeral as a placeholder, the first widely acknowledged use of zero was in 876. The original numerals were very similar to the ones, even down to the glyphs used to represent digits
11.
Floating-point arithmetic
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In computing, floating-point arithmetic is arithmetic using formulaic representation of real numbers as an approximation so as to support a trade-off between range and precision. A number is, in general, represented approximately to a number of significant digits and scaled using an exponent in some fixed base. For example,1.2345 =12345 ⏟ significand ×10 ⏟ base −4 ⏞ exponent, the term floating point refers to the fact that a numbers radix point can float, that is, it can be placed anywhere relative to the significant digits of the number. This position is indicated as the exponent component, and thus the floating-point representation can be thought of as a kind of scientific notation. The result of dynamic range is that the numbers that can be represented are not uniformly spaced. Over the years, a variety of floating-point representations have been used in computers, however, since the 1990s, the most commonly encountered representation is that defined by the IEEE754 Standard. A floating-point unit is a part of a computer system designed to carry out operations on floating point numbers. A number representation specifies some way of encoding a number, usually as a string of digits, there are several mechanisms by which strings of digits can represent numbers. In common mathematical notation, the string can be of any length. If the radix point is not specified, then the string implicitly represents an integer, in fixed-point systems, a position in the string is specified for the radix point. So a fixed-point scheme might be to use a string of 8 decimal digits with the point in the middle. The scaling factor, as a power of ten, is then indicated separately at the end of the number, floating-point representation is similar in concept to scientific notation. Logically, a floating-point number consists of, A signed digit string of a length in a given base. This digit string is referred to as the significand, mantissa, the length of the significand determines the precision to which numbers can be represented. The radix point position is assumed always to be somewhere within the significand—often just after or just before the most significant digit and this article generally follows the convention that the radix point is set just after the most significant digit. A signed integer exponent, which modifies the magnitude of the number, using base-10 as an example, the number 7005152853504700000♠152853.5047, which has ten decimal digits of precision, is represented as the significand 1528535047 together with 5 as the exponent. In storing such a number, the base need not be stored, since it will be the same for the range of supported numbers. Symbolically, this value is, s b p −1 × b e, where s is the significand, p is the precision, b is the base
12.
Exponentiation
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Exponentiation is a mathematical operation, written as bn, involving two numbers, the base b and the exponent n. The exponent is usually shown as a superscript to the right of the base, Some common exponents have their own names, the exponent 2 is called the square of b or b squared, the exponent 3 is called the cube of b or b cubed. The exponent −1 of b, or 1 / b, is called the reciprocal of b, when n is a positive integer and b is not zero, b−n is naturally defined as 1/bn, preserving the property bn × bm = bn + m. The definition of exponentiation can be extended to any real or complex exponent. Exponentiation by integer exponents can also be defined for a variety of algebraic structures. The term power was used by the Greek mathematician Euclid for the square of a line, archimedes discovered and proved the law of exponents, 10a 10b = 10a+b, necessary to manipulate powers of 10. In the late 16th century, Jost Bürgi used Roman numerals for exponents, early in the 17th century, the first form of our modern exponential notation was introduced by Rene Descartes in his text titled La Géométrie, there, the notation is introduced in Book I. Nicolas Chuquet used a form of notation in the 15th century. The word exponent was coined in 1544 by Michael Stifel, samuel Jeake introduced the term indices in 1696. In the 16th century Robert Recorde used the square, cube, zenzizenzic, sursolid, zenzicube, second sursolid. Biquadrate has been used to refer to the power as well. Some mathematicians used exponents only for greater than two, preferring to represent squares as repeated multiplication. Thus they would write polynomials, for example, as ax + bxx + cx3 + d, another historical synonym, involution, is now rare and should not be confused with its more common meaning. In 1748 Leonhard Euler wrote consider exponentials or powers in which the exponent itself is a variable and it is clear that quantities of this kind are not algebraic functions, since in those the exponents must be constant. With this introduction of transcendental functions, Euler laid the foundation for the introduction of natural logarithm as the inverse function for y = ex. The expression b2 = b ⋅ b is called the square of b because the area of a square with side-length b is b2, the expression b3 = b ⋅ b ⋅ b is called the cube of b because the volume of a cube with side-length b is b3. The exponent indicates how many copies of the base are multiplied together, for example,35 =3 ⋅3 ⋅3 ⋅3 ⋅3 =243. The base 3 appears 5 times in the multiplication, because the exponent is 5
13.
NCR Corporation
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They also provide IT maintenance support services. NCR had been based in Dayton, Ohio, starting in 1884, NCR was founded in 1884 and acquired by AT&T in 1991. A restructuring of AT&T in 1996 led to NCRs re-establishment January 1,1997 as a separate company, NCR is the only AT&T spin-off company that has retained its original name—all the others have either been purchased or renamed following subsequent mergers. The company began as the National Manufacturing Company of Dayton, Ohio, was established to manufacture, in 1884, the company and patents were bought by John Henry Patterson and his brother Frank Jefferson Patterson, and the firm was renamed the National Cash Register Company. Patterson formed NCR into one of the first modern American companies by introducing new, aggressive sales methods and he established the first sales training school in 1893 and introduced a comprehensive social welfare program for his factory workers. Other significant figures in the history of the company were Charles F. Kettering, Thomas J. Watson, Sr. Deeds and Kettering went on to found Dayton Engineering Laboratories Company which later became Delco Products Division of General Motors, Watson eventually worked his way up to general sales manager. At an uninspiring sales meeting, Watson interrupted, saying The trouble with one of us is that we dont think enough. We dont get paid for working with our feet — we get paid for working with our heads, Watson then wrote THINK on the easel. Signs with this motto were erected in factory buildings, sales offices, THINK later became a widely known symbol of IBM. Kettering designed the first cash register powered by a motor in 1906. Within a few years he developed the Class 1000 register which was in production for 40 years, telephone Credit Authorization system for verifying credit in department stores. When John H. Patterson and his brother took over the company, cash registers were expensive, there was little demand for the expensive device, but Patterson believed the product would sell once shopkeepers understood it would drastically decrease theft by salesclerks. He created a team known as the American Selling Force which worked on commissions and followed a standard sales script. The philosophy was to sell a business rather than just a piece of machinery. Sales demonstrations were set up in hotels depicting a store interior complete with real merchandise, the sale prospect was described as the P. P. or Probable Purchaser. Once initial objections were swept aside and the P. P. admitted to internal theft losses, the deal was sealed with a 25 cent cigar. NCR expanded quickly and became multi-national in 1888, between 1893 and 1906 it acquired a number of smaller cash register companies
14.
Triad (computing)
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In computing and telecommunications, a unit of information is the capacity of some standard data storage system or communication channel, used to measure the capacities of other systems and channels. In information theory, units of information are used to measure the information contents or entropy of random variables. The most common units are the bit, the capacity of a system which can exist in two states, and the byte, which is equivalent to eight bits. Multiples of these units can be formed from these with the SI prefixes or the newer IEC binary prefixes, information capacity is a dimensionless quantity. In particular, if b is an integer, then the unit is the amount of information that can be stored in a system with N possible states. When b is 2, the unit is the shannon, equal to the content of one bit. A system with 8 possible states, for example, can store up to log28 =3 bits of information, other units that have been named include, Base b =3, the unit is called trit, and is equal to log23 bits. Base b =10, the unit is called decimal digit, hartley, ban, decit, or dit, Base b = e, the base of natural logarithms, the unit is called a nat, nit, or nepit, and is worth log2 e bits. Several conventional names are used for collections or groups of bits, a byte can represent 256 distinct values, such as the integers 0 to 255, or -128 to 127. The IEEE 1541-2002 standard specifies B as the symbol for byte, bytes, or multiples thereof, are almost always used to specify the sizes of computer files and the capacity of storage units. Most modern computers and peripheral devices are designed to manipulate data in whole bytes or groups of bytes, a group of four bits, or half a byte, is sometimes called a nibble or nybble. This unit is most often used in the context of number representations. Computers usually manipulate bits in groups of a size, conventionally called words. The number of bits in a word is defined by the size of the registers in the computers CPU. Some machine instructions and computer number formats use two words, or four words, computer memory caches usually operate on blocks of memory that consist of several consecutive words. These units are customarily called cache blocks, or, in CPU caches, virtual memory systems partition the computers main storage into even larger units, traditionally called pages. Terms for large quantities of bits can be formed using the range of SI prefixes for powers of 10, e. g. kilo =103 =1000, mega- =106 =1000000. These prefixes are often used for multiples of bytes, as in kilobyte, megabyte