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π Mach kernel
Mach () is a kernel developed at Carnegie Mellon University to support operating system research, primarily distributed and parallel computing. Mach is often mentioned as one of the earliest examples of a microkernel. However, not all versions of Mach are microkernels. Mach's derivatives are the basis of the operating system kernel in GNU Hurd and of Apple's XNU kernel used in macOS, iOS, iPadOS, tvOS, and watchOS.
The project at Carnegie Mellon ran from 1985 to 1994, ending with Mach 3.0, which is a true microkernel. Mach was developed as a replacement for the kernel in the BSD version of Unix, so no new operating system would have to be designed around it. Mach and its derivatives exist within a number of commercial operating systems. These include all using the XNU operating system kernel which incorporates an earlier non-microkernel Mach as a major component. The Mach virtual memory management system was also adopted in 4.4BSD by the BSD developers at CSRG, and appears in modern BSD-derived Unix systems, such as FreeBSD.
Mach is the logical successor to Carnegie Mellon's Accent kernel. The lead developer on the Mach project, Richard Rashid, has been working at Microsoft since 1991 in various top-level positions revolving around the Microsoft Research division. Another of the original Mach developers, Avie Tevanian, was formerly head of software at NeXT, then Chief Software Technology Officer at Apple Inc. until March 2006.
Discussed on
- "Mach kernel" | 2019-09-05 | 139 Upvotes 95 Comments
π Crimson Contagion
Crimson Contagion was a simulation administered by the U.S. Department of Health and Human Services from January to August 2019 that tested the capacity of the U.S. federal government and twelve U.S. states to respond to a severe influenza pandemic originating in China. The exercise involves a scenario in which tourists returning from China spread a respiratory virus in the United States, beginning in Chicago. In less than two months the virus had infected 110 million Americans, killing more than half a million. The report issued at the conclusion of the exercise outlines the government's limited capacity to respond to a pandemic, with federal agencies lacking the funds, coordination, and resources to facilitate an effective response to the virus.
Discussed on
- "Crimson Contagion" | 2020-04-20 | 175 Upvotes 91 Comments
π Posterous
Posterous was a simple blogging platform started in May 2008. It supported integrated and automatic posting to other social media tools such as Flickr, Twitter, and Facebook, a built-in Google Analytics package, and custom themes. It was based in San Francisco and funded by Y Combinator.
Updating to Posterous was similar to other blogging platforms. Posting could be done by logging into the website's rich text editor, but it was particularly designed for mobile blogging. Mobile methods include sending an email, with attachments of photos, MP3s, documents, and video (both links and files). Many social media pundits considered Posterous to be the leading free application for lifestreaming. The platform received wide attention when leading social media expert Steve Rubel declared he was moving his blogging activity entirely to Posterous.
Posterous also had its own URL shortening service, which as of March 2010 could post to Twitter.
Posterous allowed users to point the DNS listing for a domain name or subdomain they already owned to their Posterous account, allowing them to have a site hosted by Posterous that used their own domain name.
In January 2010, the3six5, a Posterous-based storytelling project, launched. It was nominated for a Webby Award in 2011.
In May 2010, Posterous was recognized as one of the β2010 Hottest Silicon Valley Companiesβ by Lead411.
Discussed on
- "Posterous" | 2020-03-11 | 10 Upvotes 4 Comments
π Nuclear Football
The nuclear football (also known as the atomic football, the president's emergency satchel, the Presidential Emergency Satchel, the button, the black box, or just the football) is a briefcase, the contents of which are to be used by the President of the United States to authorize a nuclear attack while away from fixed command centers, such as the White House Situation Room. It functions as a mobile hub in the strategic defense system of the United States. It is held by an aide-de-camp.
π Low-Background Steel
Low-background steel is any steel produced prior to the detonation of the first nuclear bombs in the 1940s and 1950s. With the Trinity test and the nuclear bombings of Hiroshima and Nagasaki in 1945, and then subsequent nuclear weapons testing during the early years of the Cold War, background radiation levels increased across the world. Modern steel is contaminated with radionuclides because its production uses atmospheric air. Low-background steel is so-called because it does not suffer from such nuclear contamination. This steel is used in devices that require the highest sensitivity for detecting radionuclides.
The primary source of low-background steel is ships that were constructed before the Trinity test, most famously the scuttled German World War I warships in Scapa Flow.
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- "Low-Background Steel" | 2021-10-24 | 27 Upvotes 3 Comments
- "Low-Background Steel" | 2020-07-19 | 359 Upvotes 107 Comments
- "Low-background steel" | 2016-06-19 | 159 Upvotes 28 Comments
- "Low-background Steel" | 2013-10-25 | 30 Upvotes 13 Comments
π Quantum tic tac toe: A teaching metaphor for superposition in quantum mechanics
Quantum tic-tac-toe is a "quantum generalization" of tic-tac-toe in which the players' moves are "superpositions" of plays in the classical game. The game was invented by Allan Goff of Novatia Labs, who describes it as "a way of introducing quantum physics without mathematics", and offering "a conceptual foundation for understanding the meaning of quantum mechanics".
Discussed on
- "Quantum tic tac toe: A teaching metaphor for superposition in quantum mechanics" | 2009-07-22 | 23 Upvotes 3 Comments
π Greater Fool Theory
In finance, the greater fool theory suggests that one can sometimes make money through the purchase of overvalued assetsβββitems with a purchase price drastically exceeding the intrinsic valueβββif those assets can later be resold at an even higher price.
In this context, one "fool" might pay for an overpriced asset, on the assumption that he can probably sell it to an even "greater fool" and make a profit. This only works as long as there are new "greater fools" willing to pay higher and higher prices for the asset. Eventually, investors can no longer deny that the price is out of touch with reality, at which point a sell-off can cause the price to drop significantly until it is closer to its fair value.
Discussed on
- "Greater Fool Theory" | 2022-01-30 | 12 Upvotes 2 Comments
π Buddhas of Bamiyan
The Buddhas of Bamiyan were two 6th-century monumental statues of Vairocana Buddha and Gautama Buddha carved into the side of a cliff in the Bamyan valley of central Afghanistan, 130 kilometres (81Β mi) northwest of Kabul at an elevation of 2,500 metres (8,200Β ft). Carbon dating of the structural components of the Buddhas has determined that the smaller 38Β m (125Β ft) "Eastern Buddha" was built around 570 AD, and the larger 55Β m (180Β ft) "Western Buddha" was built around 618 AD.
The statues represented a later evolution of the classic blended style of Gandhara art. The statues consisted of the male Salsal ("light shines through the universe") and the (smaller) female Shamama ("Queen Mother"), as they were called by the locals. The main bodies were hewn directly from the sandstone cliffs, but details were modeled in mud mixed with straw, coated with stucco. This coating, practically all of which wore away long ago, was painted to enhance the expressions of the faces, hands, and folds of the robes; the larger one was painted carmine red and the smaller one was painted multiple colors. The lower parts of the statues' arms were constructed from the same mud-straw mix supported on wooden armatures. It is believed that the upper parts of their faces were made from great wooden masks or casts. The rows of holes that can be seen in photographs held wooden pegs that stabilized the outer stucco.
The Buddhas are surrounded by numerous caves and surfaces decorated with paintings. It is thought that the period of florescence was from the 6th to 8th century AD, until the onset of Islamic invasions. These works of art are considered as an artistic synthesis of Buddhist art and Gupta art from India, with influences from the Sasanian Empire and the Byzantine Empire, as well as the country of Tokharistan.
The statues were blown up and destroyed in March 2001 by the Taliban, on orders from leader Mullah Mohammed Omar, after the Taliban government declared that they were idols. International and local opinion strongly condemned the destruction of the Buddhas. Some Taliban sources credited Omar's decision to blow up the Buddha statues to the growing influence of Osama bin Laden.
π Bribery of Senior Wehrmacht Officers
From 1933 to the end of the Second World War, high-ranking officers of the Armed Forces of Nazi Germany accepted vast bribes in the form of cash, estates, and tax exemptions in exchange for their loyalty to Nazism. Unlike bribery at lower ranks in the Wehrmacht, which was also widespread, these payments were regularized, technically legal and made with the full knowledge and consent of the leading Nazi figures.
π ST3000DM001
The ST3000DM001 is a hard disk drive released by Seagate Technology in 2011 as part of the Seagate Barracuda series. It has a capacity of 3 terabytes (TB) and a spindle speed of 7200Β RPM. This particular drive model was reported to have unusually high failure rates, approximately 5.7 times higher fail rates in comparison to other 3 TB drives.
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- "ST3000DM001" | 2021-06-07 | 270 Upvotes 250 Comments