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Hardware Bug
A hardware bug is a defect in the design, manufacture, or operation of computer hardware that causes incorrect operation. It is the counterpart of software bugs which refer to flaws in the code which operates computers, and is the original context in which " bug" was used to refer to such flaws. Intermediate between hardware and software are microcode and firmware which may also have such defects. In common usage, a bug is subtly different from a "glitch" which may be more transient than fundamental, and somewhat different from a "quirk" which may be considered useful or intrinsic. Errata (corrections to the documentation) may be published by the manufacturer to reflect such unintended operation, and "errata" is sometimes used as a term for the flaws themselves. History The Middle English word ''bugge'' is the basis for the terms "bugbear" and " bugaboo" as terms used for a monster. The term "bug" to describe defects has been a part of engineering jargon since the 1870s and preda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Hardware
Computer hardware includes the physical parts of a computer, such as the case, central processing unit (CPU), random access memory (RAM), monitor, mouse, keyboard, computer data storage, graphics card, sound card, speakers and motherboard. By contrast, software is the set of instructions that can be stored and run by hardware. Hardware is so-termed because it is " hard" or rigid with respect to changes, whereas software is "soft" because it is easy to change. Hardware is typically directed by the software to execute any command or instruction. A combination of hardware and software forms a usable computing system, although other systems exist with only hardware. Von Neumann architecture The template for all modern computers is the Von Neumann architecture, detailed in a 1945 paper by Hungarian mathematician John von Neumann. This describes a design architecture for an electronic digital computer with subdivisions of a processing unit consisting of an arithmetic log ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isaac Asimov
yi, יצחק אזימאװ , birth_date = , birth_place = Petrovichi, Russian SFSR , spouse = , relatives = , children = 2 , death_date = , death_place = Manhattan, New York City, U.S. , nationality = Russian (1920–1922)Soviet (1922–1928)American (1928–1992) , occupation = Writer, professor of biochemistry , years_active = 1939–1992 , genre = Science fiction ( hard SF, social SF), mystery, popular science , subject = Popular science, science textbooks, essays, history, literary criticism , education = Columbia University ( BA, MA, PhD) , movement = Golden Age of Science Fiction , module = , signature = Isaac Asimov signature.svg Isaac Asimov ( ; 1920 – April 6, 1992) was an American writer and professor of biochemistry at Boston University. During his lifetime, Asimov was considered one of the "Big Three" science fiction writers, along with Robert A. Heinlein and Arthur C. Clarke. A prolific writer, he wrote or edited more than 500 book ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple II
The Apple II (stylized as ) is an 8-bit home computer and one of the world's first highly successful mass-produced microcomputer products. It was designed primarily by Steve Wozniak; Jerry Manock developed the design of Apple II's foam-molded plastic case, Rod Holt developed the switching power supply, while Steve Jobs's role in the design of the computer was limited to overseeing Jerry Manock's work on the plastic case. It was introduced by Jobs and Wozniak at the 1977 West Coast Computer Faire, and marks Apple's first launch of a personal computer aimed at a consumer market—branded toward American households rather than businessmen or computer hobbyists. ''Byte'' magazine referred to the Apple II, Commodore PET 2001, and TRS-80 as the "1977 Trinity". As the Apple II had the defining feature of being able to display color graphics, the Apple logo was redesigned to have a spectrum of colors. The Apple II is the first model in the Apple II series, followed by A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MOS Technology 6502
The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small team led by Chuck Peddle for MOS Technology. The design team had formerly worked at Motorola on the Motorola 6800 project; the 6502 is essentially a simplified, less expensive and faster version of that design. When it was introduced in 1975, the 6502 was the least expensive microprocessor on the market by a considerable margin. It initially sold for less than one-sixth the cost of competing designs from larger companies, such as the 6800 or Intel 8080. Its introduction caused rapid decreases in pricing across the entire processor market. Along with the Zilog Z80, it sparked a series of projects that resulted in the home computer revolution of the early 1980s. Popular video game consoles and home computers of the 1980s and early 1990s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore 64
The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness World Records as the highest-selling single computer model of all time, with independent estimates placing the number sold between 12.5 and 17 million units. Volume production started in early 1982, marketing in August for . Preceded by the VIC-20 and Commodore PET, the C64 took its name from its of RAM. With support for multicolor sprites and a custom chip for waveform generation, the C64 could create superior visuals and audio compared to systems without such custom hardware. The C64 dominated the low-end computer market (except in the UK and Japan, lasting only about six months in Japan) for most of the later years of the 1980s. For a substantial period (1983–1986), the C64 had between 30% and 40% share of the US market and two mil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MOS Technology 6510
300px, Image of the internals of a Commodore 64 showing the 6510 CPU (40-pin DIP, lower left). The chip on the right is the 6581 SID. The production week/year (WWYY) of each chip is given below its name. The MOS Technology 6510 is an 8-bit microprocessor designed by MOS Technology. It is a modified form of the very successful 6502. The 6510 is widely used in the Commodore 64 (C64) home computer and its variants. The primary change from the 6502 is the addition of an 8-bit general purpose I/O port, although 6 I/O pins are available in the most common version of the 6510. In addition, the address bus can be made tristate and the CPU can be halted cleanly. Use In the C64, the extra I/O pins of the processor are used to control the computer's memory map by bank switching, and for controlling three of the four signal lines of the Datasette tape recorder (the electric motor control, key-press sensing and write data lines; the read data line went to another I/O chip). It is poss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Museum Of American History
The National Museum of American History: Kenneth E. Behring Center collects, preserves, and displays the heritage of the United States in the areas of social, political, cultural, scientific, and military history. Among the items on display is the original Star-Spangled Banner. The museum is part of the Smithsonian Institution and located on the National Mall at 14th Street and Constitution Avenue NW in Washington, D.C. History The museum opened in 1964 as the Museum of History and Technology. It was one of the last structures designed by the renowned architectural firm McKim Mead & White. In 1980, the museum was renamed the National Museum of American History to represent its mission of the collection, care, study, and interpretation of objects that reflect the experience of the American people. The museum site had previously held two temporary war buildings constructed in 1942. In May 2012, John Gray became the new director. He retired from the post in May 2018 and was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dahlgren, Virginia
Dahlgren is an unincorporated community and census-designated place (CDP) in King George County, Virginia, United States. The population was 2,946 at the time of the 2020 census, up from 2,653 at the 2010 census, and up from 997 in 2000. History Since 1918, Dahlgren has been the site of a U.S. naval base named for Rear Admiral John A. Dahlgren. It was first the "U.S. Naval Proving Ground" but was renamed the "U.S. Naval Weapons Laboratory" after 1950, the "Naval Surface Weapons Center" in 1974, the "Naval Surface Warfare Center" in 1987, and the "U.S. Naval Surface Warfare Center Dahlgren Division (NSWCDD)" around 1990. In 2006, it was renamed "Naval Support Activity-South Potomac (NSA-SP)", with NSWCDD becoming a tenant command of the base. The U.S. Naval Space Surveillance Systems command was located at that base, but that responsibility was transferred to the Air Force in 2004. The AEGIS Training and Readiness Center is currently a tenant command at NSA-SP. The naval base lies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naval Surface Warfare Center Dahlgren Division
The United States Naval Surface Warfare Center Dahlgren Division (NSWCDD), named for Rear Admiral John A. Dahlgren, is located in King George County, Virginia, in close proximity to the largest fleet concentration area in the Navy. NSWCDD is part of the Naval Surface Warfare Centers under the Naval Sea Systems Command (NAVSEA). NSWCDD was initially established 16 October 1918 as a remote extension of Maryland's Indian Head Proving Ground used for testing naval guns. The Dahlgren site was named the Lower Station, Dahlgren Naval Proving Ground when it first opened. The location on the Potomac River was specifically chosen for the development of a long ballistic test range on the Potomac River, required for the testing of modern, high-powered munitions.http://namdc.ahf.nmci.navy.mil/site%20pages/news/03-29-13_NSF_Dahlgren_profile_2013.pdf The NSWCDD employs approximately 4,700 scientists, engineers and support personnel at the Dalhgren organization and more than 350 at NSWCDD ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moth
Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of which have yet to be described. Most species of moth are nocturnal, but there are also crepuscular and diurnal species. Differences between butterflies and moths While the butterflies form a monophyletic group, the moths, comprising the rest of the Lepidoptera, do not. Many attempts have been made to group the superfamilies of the Lepidoptera into natural groups, most of which fail because one of the two groups is not monophyletic: Microlepidoptera and Macrolepidoptera, Heterocera and Rhopalocera, Jugatae and Frenatae, Monotrysia and Ditrysia.Scoble, MJ 1995. The Lepidoptera: Form, function and diversity. Oxford, UK: Oxford University Press; 404 p. Although the rules for distinguishing moths from butterflies are not well establishe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harvard Mark III
The Harvard Mark III, also known as ADEC (for Aiken Dahlgren Electronic Calculator) was an early computer that was partially electronic and partially electromechanical. It was built at Harvard University under the supervision of Howard Aiken for the U.S. Navy. Technical overview The Mark III processed numbers of 16 decimal digits (plus sign), each digit encoded with four bits, though using a form of encoding that is different to conventional binary-coded decimal today. Numbers were read and processed serially, meaning one decimal digit at a time, but the four bits for the digit were read in parallel. The instruction length, however, was 38 bits, read in parallel. It used 5,000 vacuum tubes and 1,500 crystal diodes. It weighed . It used magnetic drum memory of 4,350 words. Its addition time was 4,400 microseconds and the multiplication time was 13,200 microseconds (times include memory access time). Aiken boasted that the Mark III was the fastest electronic computer in the world. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harvard Mark II
The Harvard Mark II, also known as the Aiken Relay Calculator, was an electromechanical computer built under the direction of Howard Aiken at Harvard University, completed in 1947. It was financed by the United States Navy and used for ballistic calculations at Naval Proving Ground Dahlgren. Howard Aiken and Grace Hopper worked together to build and program the Mark II. Overview The contract to build the Mark II was signed with Harvard in February 1945, after the successful demonstration of the Mark I in 1944. It was completed and debugged in 1947, and delivered to the US Navy Proving Ground at Dahlgren, Virginia in March 1948, becoming fully operational by the end of that year. The Mark II was constructed with high-speed electromagnetic relays instead of the electro-mechanical counters used in the Mark I, making it much faster than its predecessor. It weighed and occupied over of floor space. Its addition time was 0.125 seconds (8 Hz) and the multiplication time was 0. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
