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π Jadi
Amir Emad Mirmirani (Persian: Ψ§Ω ΫΨ±ΨΉΩ Ψ§Ψ― Ω ΫΨ±Ω ΫΨ±Ψ§ΩΫ) known by the nickname Jadi, is a programmer, blogger and internet activist in the field of Free and open-source software and Linux in Iran. He was arrested in October 2022 during the Iranian protests following the death of Mahsa Amini.
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- "Jadi" | 2022-11-01 | 11 Upvotes 1 Comments
π Pizza box form factor
In computing, a pizza box is a style of case design for desktop computers or network switches. Pizza box cases tend to be wide and flat, normally 1.5 to 4 inches or 4 to 10 centimetres in height, resembling pizza delivery boxes and thus the name. This is in contrast to a tower system, whose case height is much greater than the width and has an "upright" appearance. In modern usage, the term "pizza box" is normally reserved for very flat cases with height no more than 2 inches (51Β mm), while those taller than 2 inches are referred to as desktop cases instead.
The common setup of a pizza box system is to have the display monitor placed directly on top of the case, which serves as a podium to elevate the monitor more towards the user's eye level, and to have other peripherals placed in front and alongside the case. Occasionally, the pizza box may be laid on its sides in a tower-like orientation.
Data General's Aviion Unix server was the first to coin the expression when it advertised in 1991 with the tagline "Who just fit mainframe power in a pizza box?", but most computers generally referred to as pizza box systems were high-end desktop systems such as Sun Microsystems workstations sold in the 1990s, most notably the SPARCstationΒ 1 and SPARCstationΒ 5. Other notable examples have been among the highest-performing desktop computers of their generations, including the SGIΒ Indy, the NeXTstation, and the Amiga 1000, but the form factor was also seen in budget and lower-end lines such as the Macintosh LC family.
The original SPARCstationΒ 1 design included an expansion bus technology, SBus, expressly designed for the form factor; expansion cards were small, especially in comparison to other expansion cards in use at the time such as VMEbus, and were mounted horizontally instead of vertically. PC-compatible computers in this type of case typically use the PCI expansion bus and are usually either a)Β limited to one or two horizontally placed expansion cards or b)Β require special low-profile expansion cards, shorter than the PCIΒ cards regular PCs use.
The density of computing power and stackability of pizza box systems also made them attractive for use in data centers. Systems originally designed for desktop use were placed on shelves inside of 19-inch racks, sometimes requiring that part of their cases be cut off for them to fit. Since the late 1990s, pizza boxes have been a common form factor in office cubicles, data centers or industrial applications, where desktop space, rack room and density are critical. Servers in this form factor, as well as higher-end Ethernet switches, are now designed for rack mounting. Rack mount 1U computers come in all types of configurations and depths.
The pizza box form factor for smaller personal systems and thin clients remains in use well into the 21st century, though it is increasingly being superseded by laptops, nettops or All-in-One PC designs that embed the already size-reduced computer onto the keyboard or display monitor.
π MKUltra
Project MKUltra was an illegal human experiments program designed and undertaken by the U.S. Central Intelligence Agency (CIA) to develop procedures and identify drugs that could be used during interrogations to weaken people and force confessions through brainwashing and psychological torture. It began in 1953 and was halted in 1973. MKUltra used numerous methods to manipulate its subjects' mental states and brain functions, such as the covert administration of high doses of psychoactive drugs (especially LSD) and other chemicals without the subjects' consent, electroshocks, hypnosis, sensory deprivation, isolation, verbal and sexual abuse, and other forms of torture.
MKUltra was preceded by Project Artichoke. It was organized through the CIA's Office of Scientific Intelligence and coordinated with the United States Army Biological Warfare Laboratories. The program engaged in illegal activities, including the use of U.S. and Canadian citizens as unwitting test subjects.:β74β MKUltra's scope was broad, with activities carried out under the guise of research at more than 80 institutions aside from the military, including colleges and universities, hospitals, prisons, and pharmaceutical companies. The CIA operated using front organizations, although some top officials at these institutions were aware of the CIA's involvement.
MKUltra was revealed to the public in 1975 by the Church Committee of the United States Congress and Gerald Ford's United States President's Commission on CIA activities within the United States (the Rockefeller Commission). Investigative efforts were hampered by CIA Director Richard Helms's order that all MKUltra files be destroyed in 1973; the Church Committee and Rockefeller Commission investigations relied on the sworn testimony of direct participants and on the small number of documents that survived Helms's order. In 1977, a Freedom of Information Act request uncovered a cache of 20,000 documents relating to MKUltra, which led to Senate hearings. Some surviving information about MKUltra was declassified in 2001.
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- "MKUltra" | 2024-05-16 | 97 Upvotes 94 Comments
π Pink Noise
Pink noise or β1βf noise is a signal or process with a frequency spectrum such that the power spectral density (energy or power per frequency interval) is inversely proportional to the frequency of the signal. In pink noise, each octave (halving or doubling in frequency) carries an equal amount of noise energy.
Pink noise is one of the most common signals in biological systems.
The name arises from the pink appearance of visible light with this power spectrum. This is in contrast with white noise which has equal intensity per frequency interval.
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- "Pink Noise" | 2019-09-27 | 10 Upvotes 4 Comments
π Poppy Seed Defence
The poppy seed defence is a commonly cited reason to avoid any sanction for failing a drug test. The defence asserts that a suspect's positive result was a result of the person having consumed poppy seeds prior to taking the test. It has been recognised in medical and legal fields as a valid defence.
π List of Countries by Vehicles per Capita
This article is a list of countries by the number of road motor vehicles per 1,000 inhabitants. This includes cars, vans, buses, and freight and other trucks; but excludes motorcycles and other two-wheelers.
China has the largest fleet of motor vehicles in the world in 2021, with 292 million cars, and in 2009 became the world's largest new car market as well. In 2011, a total of 80 million cars and commercial vehicles were built, led by China, with 18.4 million motor vehicles manufactured.
π Williamson Amplifier
The Williamson amplifier is a four-stage, push-pull, Class A triode-output valve audio power amplifier designed by D. T. N. Williamson during World War II. The original circuit, published in 1947 and addressed to the worldwide do it yourself community, set the standard of high fidelity sound reproduction and served as a benchmark or reference amplifier design throughout the 1950s. The original circuit was copied by hundreds of thousands amateurs worldwide. It was an absolute favourite on the DIY scene of the 1950s, and in the beginning of the decade also dominated British and North American markets for factory-assembled amplifiers.
The Williamson circuit was based on the 1934 Wireless World Quality Amplifier by Walter Cocking, with an additional error amplifier stage and a global negative feedback loop. Deep feedback, triode-connected KT66 power tetrodes, conservative choice of standing currents, and the use of wide-bandwidth output transformer all contributed to the performance of the Williamson. It had a modest output power rating of 15Β Watts but surpassed all contemporary designs in having very low harmonic distortion and intermodulation, flat frequency response throughout the audible frequency range, and effective damping of loudspeaker resonances. The 0.1% distortion figure of the Williamson amplifier became the criterion for high fidelity performance that remains valid in the 21st century.
The Williamson amplifier was sensitive to selection and matching of passive components and valves, and prone to unwanted oscillations at infrasonic and ultrasonic frequencies. Enclosing four valve stages and an output transformer in a negative feedback loop was a severe test of design, resulting in a very narrow phase margin or, quite often, no margin at all. Attempts to improve stability of the Williamson could not fix this fundamental flaw. For this reason, and due to high costs of required quality components, manufacturers soon abandoned the Williamson circuit in favour of inherently more stable, cheaper and efficient three-stage, ultralinear or pentode-output designs.
π Wikipedia's robots.txt
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- "Wikipedia's Robot.txt" | 2021-03-26 | 17 Upvotes 3 Comments
- "Wikipedia's robots.txt" | 2019-07-16 | 105 Upvotes 38 Comments
- "The wikipedia robots.txt" | 2011-10-28 | 42 Upvotes 3 Comments
π Secure Remote Password protocol
The Secure Remote Password protocol (SRP) is an augmented password-authenticated key agreement (PAKE) protocol, specifically designed to work around existing patents.
Like all PAKE protocols, an eavesdropper or man in the middle cannot obtain enough information to be able to brute force guess a password without further interactions with the parties for each guess. Furthermore, being an augmented PAKE protocol, the server does not store password-equivalent data. This means that an attacker who steals the server data cannot masquerade as the client unless they first perform a brute force search for the password.
In layman's terms, during SRP (or any other PAKE protocol) authentication, one party (the "client" or "user") demonstrates to another party (the "server") that they know the password, without sending the password itself nor any other information from which the password can be derived. The password never leaves the client and is unknown to the server.
Furthermore, the server also needs to know about the password (but not the password itself) in order to instigate the secure connection. This means that the server also authenticates itself to the client, without reliance on the user parsing complex URLs. This prevents Phishing.
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- "Secure Remote Password protocol" | 2017-04-11 | 17 Upvotes 19 Comments
π The 480
The 480 is a political fiction novel by Eugene Burdick (1964).
The plot evolves around the political turmoil after John F. Kennedy assassination in 1963. In the novel, a fictitious charismatic character, John Thatch, an engineer, is seeking nomination for the Republican Party candidate at 1964 presidential elections. He is described as being contaminated with the "political virus". A handful of political professionals are promoting his nomination, in confrontation with the Party establishment. There exist apparent parallels between Thatch and Henry Cabot Lodge, Jr., a write-in hero at New Hampshire primary.
The novel criticizes the socio-political effects on society at large from the use of computers to run massive simulations, which predict the public reaction to certain (proposed) political moves before implementing them. Such simulations make it easy to manipulate the public consciousness.
The "480" in the title denotes the number of groups (by party affiliation, socioeconomic status, location, origin, etc.) that the computer simulation uses to classify the American electorate. The full list of these is reproduced in the Appendix, claimed by the author to be the true list used by the Simulmatics Corporation (real name) in Senator John F. Kennedy's Presidential campaign in 1960. The cover features an IBM 5081 punched card.
The Simulmatics Corporation was created by MIT Professor Ithiel de Sola Pool, who provided a non-fiction backup to "The 480" in "Candidates, Issues, and Strategies: A Computer Simulation of the 1960 Presidential Election," MIT Press, 1964 (with co-authors Robert P. Abelson and Samuel L. Popkin). They built their model from 130,000 archived interviews in Gallup and Roper polls over a ten-year period. Based on its output, they advised Kennedy that he would benefit from a strong civil rights stand and that he had nothing to lose, and much to gain, by attacking religious bigotry and dealing frankly with his Catholicism.
The 480 has been cited as prefiguring the effect of modern social media and data gathering on politics.
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- "The 480" | 2020-03-25 | 148 Upvotes 70 Comments