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Pentium FDIV Bug
The Pentium FDIV bug is a hardware bug affecting the floating-point unit (FPU) of the early Intel Pentium processors. Because of the bug, the processor would return incorrect binary floating point results when dividing certain pairs of high-precision numbers. The bug was discovered in 1994 by Thomas R. Nicely, a professor of mathematics at Lynchburg College. Missing values in a lookup table used by the FPU's floating-point division algorithm led to calculations acquiring small errors. While these errors would in most use-cases only occur rarely and result in small deviations from the correct output values, in certain circumstances the errors can occur frequently and lead to more significant deviations. The severity of the FDIV bug is debated. Though rarely encountered by most users (''Byte'' magazine estimated that 1 in 9 billion floating point divides with random parameters would produce inaccurate results), both the flaw and Intel's initial handling of the matter were heavily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KL Intel Pentium A80501
KL, kL, kl, or kl. may refer to: Businesses and organizations * KLM, a Dutch airline (IATA airline designator KL) * Koninklijke Landmacht, the Royal Netherlands Army * Kvenna Listin ("Women's List"), a political party in Iceland * KL FM, a Malay language radio station Places * Kaiserslautern, Germany (license plate code KL) * Kerala, India (ISO 3166-2:IN subcode KL) * Kirkland Lake, Ontario, Canada * Kowloon, Hong Kong * Kuala Lumpur, Malaysia Science, technology, and mathematics * KL engine, version of the Mazda K engine * Klepton (kl.), a type of species in zoology * Kiloliter (kL), a unit of volume * Kullback–Leibler divergence in mathematics * KL (gene), a gene which encodes the klotho enzyme in humans Other uses * Jeep Cherokee (KL) * Kalaallisut language (ISO 639 alpha-2 language code "kl") * Kl (digraph), used in the Zulu language to write /kʟ̥ʼ/ or /kxʼ/ * Konzentrationslager, or concentration camp, abbreviated KZ or KL * ''KL – A History of the Nazi Concentratio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twin Prime
A twin prime is a prime number that is either 2 less or 2 more than another prime number—for example, either member of the twin prime pair (41, 43). In other words, a twin prime is a prime that has a prime gap of two. Sometimes the term ''twin prime'' is used for a pair of twin primes; an alternative name for this is prime twin or prime pair. Twin primes become increasingly rare as one examines larger ranges, in keeping with the general tendency of gaps between adjacent primes to become larger as the numbers themselves get larger. However, it is unknown whether there are infinitely many twin primes (the so-called twin prime conjecture) or if there is a largest pair. The breakthrough work of Yitang Zhang in 2013, as well as work by James Maynard, Terence Tao and others, has made substantial progress towards proving that there are infinitely many twin primes, but at present this remains unsolved. Properties Usually the pair (2, 3) is not considered to be a pair of twin primes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formal Verification
In the context of hardware and software systems, formal verification is the act of proving or disproving the correctness of intended algorithms underlying a system with respect to a certain formal specification or property, using formal methods of mathematics. Formal verification can be helpful in proving the correctness of systems such as: cryptographic protocols, combinational circuits, digital circuits with internal memory, and software expressed as source code. The verification of these systems is done by providing a formal proof on an abstract mathematical model of the system, the correspondence between the mathematical model and the nature of the system being otherwise known by construction. Examples of mathematical objects often used to model systems are: finite-state machines, labelled transition systems, Petri nets, vector addition systems, timed automata, hybrid automata, process algebra, formal semantics of programming languages such as operational semantics, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Relations
Public relations (PR) is the practice of managing and disseminating information from an individual or an organization (such as a business, government agency, or a nonprofit organization) to the public in order to influence their perception. Public relations and publicity differ in that PR is controlled internally, whereas publicity is not controlled and contributed by external parties. Public relations may include an organization or individual gaining exposure to their audiences using topics of public interest and news items that do not require direct payment. The exposure mostly is media-based. This differentiates it from advertising as a form of marketing communications. Public relations aims to create or obtain coverage for clients for free, also known as earned media, rather than paying for marketing or advertising also known as paid media. But in the early 21st century, advertising is also a part of broader PR activities. An example of good public relations would be ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brun's Constant
In number theory, Brun's theorem states that the sum of the reciprocals of the twin primes (pairs of prime numbers which differ by 2) converges to a finite value known as Brun's constant, usually denoted by ''B''2 . Brun's theorem was proved by Viggo Brun in 1919, and it has historical importance in the introduction of sieve methods. Asymptotic bounds on twin primes The convergence of the sum of reciprocals of twin primes follows from bounds on the density of the sequence of twin primes. Let \pi_2(x) denote the number of primes ''p'' ≤ ''x'' for which ''p'' + 2 is also prime (i.e. \pi_2(x) is the number of twin primes with the smaller at most ''x''). Then, for ''x'' ≥ 3, we have : \pi_2(x) =O\left(\frac \right). That is, twin primes are less frequent than prime numbers by nearly a logarithmic factor. It follows from this bound that the sum of the reciprocals of the twin primes converges, or stated in other words, the twin primes form a small set. In explicit terms the su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science (journal)
''Science'', also widely referred to as ''Science Magazine'', is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals. It was first published in 1880, is currently circulated weekly and has a subscriber base of around 130,000. Because institutional subscriptions and online access serve a larger audience, its estimated readership is over 400,000 people. ''Science'' is based in Washington, D.C., United States, with a second office in Cambridge, UK. Contents The major focus of the journal is publishing important original scientific research and research reviews, but ''Science'' also publishes science-related news, opinions on science policy and other matters of interest to scientists and others who are concerned with the wide implications of science and technology. Unlike most scientific journals, which focus on a specific field, ''Science'' and its rival ''Nature (journal), Nature'' c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PowerPC
PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple Inc., Apple–IBM–Motorola alliance, known as AIM alliance, AIM. PowerPC, as an evolving instruction set, has been named Power ISA since 2006, while the old name lives on as a trademark for some implementations of Power Architecture–based processors. PowerPC was the cornerstone of AIM's PReP and Common Hardware Reference Platform (CHRP) initiatives in the 1990s. Originally intended for personal computers, the architecture is well known for being used by Apple's Power Macintosh, PowerBook, iMac, iBook, eMac, Mac Mini, and Xserve lines from 1994 until 2005, when Mac transition to Intel processors, Apple migrated to Intel's x86. It has since become a niche in personal computers, but remains popular for embedded system, embedded and high-performanc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Engineering Times
''EE Times'' (''Electronic Engineering Times'') is an electronics industry magazine published in the United States since 1972. EE Times is currently owned by AspenCore, a division of Arrow Electronics since August 2016. Since its acquisition by AspenCore, EE Times has seen major editorial and publishing technology investment and a renewed emphasis on investigative coverage. New features include The Dispatch, which profiles frontline engineers and unpacks the real-life design problems and their solutions in technical yet conversational reporting. Ownership and status ''EE Times'' was launched in 1972 by Gerard G. Leeds of CMP Publications Inc. In 1999, the Leeds family sold CMP to United Business Media for $900 million. After 2000, ''EE Times'' moved more into web publishing. The shift in advertising from print to online began to accelerate in 2007 and the periodical shed staff to adjust to the downturn in revenue. In July 2013, the digital edition migrated to UBM TechWeb's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X86 Instruction Listings
The x86 instruction set refers to the set of instructions that x86-compatible microprocessors support. The instructions are usually part of an executable program, often stored as a computer file and executed on the processor. The x86 instruction set has been extended several times, introducing wider registers and datatypes as well as new functionality. x86 integer instructions Below is the full 8086/8088 instruction set of Intel (81 instructions total). Most if not all of these instructions are available in 32-bit mode; they just operate on 32-bit registers (eax, ebx, etc.) and values instead of their 16-bit (ax, bx, etc.) counterparts. The updated instruction set is also grouped according to architecture (i386, i486, i686) and more generally is referred to as (32-bit) x86 and (64-bit) x86-64 (also known as AMD64). Original 8086/8088 instructions Added in specific Intel processors Added with 80186/ 80188 Added with 80286 Added with 80386 Compared to ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mail, telephony, and file sharing. The origins of the Internet date back to the development of packet switching and research commissioned by the United States Department of Defense in the 1960s to enable time-sharing of computers. The primary precursor network, the ARPANET, initially served as a backbone for interconnection of regional academic and military networks in the 1970s to enable resource shari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentium Compatible Processor
The Pentium (also referred to as P5, its microarchitecture, or i586) is a fifth generation, 32-bit x86 microprocessor that was introduced by Intel on March 22, 1993, as the very first CPU in the Pentium brand. It was instruction set compatible with the 80486 but was a new and very different microarchitecture design from previous iterations. The P5 Pentium was the first superscalar x86 microarchitecture and the world's first superscalar microprocessor to be in mass productionmeaning it generally executes at least 2 instructions per clock mainly because of a design-first dual integer pipeline design previously thought impossible to implement on a CISC microarchitecture. Additional features include a faster floating-point unit, wider data bus, separate code and data caches, and many other techniques and features to enhance performance and support security, encryption, and multiprocessing, for workstations and servers when compared to the next best previous industry standard proces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel 80486DX4
IntelDX4 is a clock-tripled i486 microprocessor with 16-kB Level 1 cache.http://www.pld.ttu.ee/~prj/486dev.pdf Intel named it DX4 (rather than ''DX3'') as a consequence of litigation with AMD over trademarks. The product was officially named IntelDX4, but OEMs continued using the i486 naming convention. Intel produced IntelDX4s with two clock speed steppings: A 75-MHz version (3× 25 MHz multiplier), and a 100-MHz version (3× 33.3 MHz). Both chips were released in March 1994. A version of IntelDX4 featuring write-back cache was released in October 1994. The original write-through versions of the chip are marked with a laser-embossed “&E,” while the write-back-enabled versions are marked “&EW.” i486 OverDrive editions of IntelDX4 had locked multipliers, and therefore can only run at 3× the external clock speed. The 100-MHz model of the processor had an iCOMP rating of 435, while the 75-MHz processor had a rating of 319. IntelDX4 was an OEM-only prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
