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🔗 Computing 🔗 Telecommunications 🔗 Computing/Software 🔗 Computing/Networking

ZMODEM is a file transfer protocol developed by Chuck Forsberg in 1986, in a project funded by Telenet in order to improve file transfers on their X.25 network. In addition to dramatically improved performance compared to older protocols, ZMODEM also offered restartable transfers, auto-start by the sender, an expanded 32-bit CRC, and control character quoting supporting 8-bit clean transfers, allowing it to be used on networks that would not pass control characters.

In contrast to most transfer protocols developed for bulletin board systems (BBSs), ZMODEM was not directly based on, nor compatible with, the seminal XMODEM. Many variants of XMODEM had been developed in order to address one or more of its shortcomings, and most remained backward compatible and would successfully complete transfers with "classic" XMODEM implementations.

ZMODEM eschewed backward compatibility in favor of producing a radically improved protocol. It performed as well or better than any of the high-performance varieties of XMODEM, did so over links that previously didn't work at all, like X.25, or had poor performance, like Telebit modems, and included useful features found in few or no other protocols. ZMODEM became extremely popular on bulletin board systems (BBS) in the early 1990s, becoming a standard as widespread as XMODEM had been before it.

🔗 Aviation 🔗 Military history 🔗 Military history/Military aviation 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/Military science, technology, and theory 🔗 Aviation/aircraft 🔗 Military history/Cold War

The Ryan Model 147 Lightning Bug is a jet-powered drone, or unmanned aerial vehicle, produced and developed by Ryan Aeronautical from the earlier Ryan Firebee target drone series.

Beginning in 1962, the Model 147 was introduced as a reconnaissance RPV (Remotely Piloted Vehicle, nomenclature of that era) for a United States Air Force project named Fire Fly. Over the next decade — assisted with secret funding from the recently formed National Reconnaissance Office along with support of the Strategic Air Command and Ryan Aeronautical's own resources — the basic Model 147 design would be developed into a diverse series of variants configured for a wide array of mission-specific roles, with multiple new systems, sensors and payloads used, modified and improved upon during the operational deployment of these drones in Southeast Asia. Missions performed by the Model 147 series RPVs included high- and low-altitude photographic and electronic aerial reconnaissance, surveillance, decoy, electronic warfare, signals intelligence, and psychological warfare.

The Ryan drones were designed without landing gear for simplicity and to save weight. Like its Firebee predecessor, the Model 147 could either be air-launched from a larger carrier aircraft or launched from the ground using a solid rocket booster; at completion of its mission the drone deployed its own recovery parachute which could be snatched in mid-air by a recovery helicopter (in a combat environment it was naturally not desired to recover the drone on, from or near enemy territory and ground or water impact could also cause damage to or loss of the drone or its payload).

At the end of the Vietnam War in 1975 the U.S. military's available funding and need for combat drones severely declined, even as Teledyne Ryan introduced further advanced developments of the Model 147 series such as the BGM-34 strike and defense suppression RPVs. Costs of maintaining the Lightning Bugs at full readiness could no longer be justified. Only by the 1990s did substantial interest, organization and funding again emerge from the U.S. Air Force and intelligence agencies to develop, acquire and widely deploy combat UAVs.

🔗 Computing 🔗 Perl

The WikiWikiWeb is the first-ever wiki, or user-editable website. It was launched on 25 March 1995 by its inventor, programmer Ward Cunningham, to accompany the Portland Pattern Repository website discussing software design patterns. The name WikiWikiWeb originally also applied to the wiki software that operated the website, written in the Perl programming language and later renamed to "WikiBase". The site is frequently referred to by its users as simply "Wiki", and a convention established among users of the early network of wiki sites that followed was that using the word with a capitalized W referred exclusively to the original site.

🔗 Paranormal 🔗 Scientology

Xenu (), also called Xemu, was, according to Scientology founder L. Ron Hubbard, the dictator of the "Galactic Confederacy" who brought billions of his people to Earth (then known as "Teegeeack") in DC-8-like spacecraft 75 million years ago, stacked them around volcanoes, and killed them with hydrogen bombs. Official Scientology scriptures hold that the thetans (immortal spirits) of these aliens adhere to humans, causing spiritual harm.

These events are known within Scientology as "Incident II", and the traumatic memories associated with them as "The Wall of Fire" or "R6 implant". The narrative of Xenu is part of Scientologist teachings about extraterrestrial civilizations and alien interventions in earthly events, collectively described as "space opera" by Hubbard. Hubbard detailed the story in Operating Thetan level III (OT III) in 1967, warning that the "R6 implant" (past trauma) was "calculated to kill (by pneumonia, etc.) anyone who attempts to solve it".

Within the Church of Scientology, the Xenu story is part of the church's secret "Advanced Technology", considered a sacred and esoteric teaching, which is normally only revealed to members who have completed a lengthy sequence of courses costing large amounts of money. The church avoids mention of Xenu in public statements and has gone to considerable effort to maintain the story's confidentiality, including legal action on the grounds of copyright and trade secrecy. Officials of the Church of Scientology widely deny or try to hide the Xenu story. Despite this, much material on Xenu has leaked to the public via court documents and copies of Hubbard's notes that have been distributed through the Internet. In commentary on the impact of the Xenu text, academic scholars have discussed and analyzed the writings by Hubbard and their place within Scientology within the contexts of science fiction, UFO religions, Gnosticism and creation myths.

🔗 Mathematics 🔗 Books 🔗 Systems

How to Solve It (1945) is a small volume by mathematician George Pólya describing methods of problem solving.

🔗 Geography 🔗 Maps

The Peirce quincuncial projection is a conformal map projection developed by Charles Sanders Peirce in 1879. The projection has the distinctive property that it can be tiled ad infinitum on the plane, with edge-crossings being completely smooth except for four singular points per tile. The projection has seen use in digital photography for portraying 360° views. The description quincuncial refers to the arrangement of four quadrants of the globe around the center hemisphere in an overall square pattern. Typically the projection is oriented such that the north pole lies at the center.

🔗 Computing 🔗 Automobiles

MISRA C is a set of software development guidelines for the C programming language developed by The MISRA Consortium. Its aims are to facilitate code safety, security, portability and reliability in the context of embedded systems, specifically those systems programmed in ISO C / C90 / C99.

There is also a set of guidelines for MISRA C++ not covered by this article.

🔗 Telecommunications 🔗 Brands

The IBM Simon Personal Communicator (simply known as IBM Simon) is a handheld, touchscreen PDA designed by International Business Machines (IBM), and manufactured by Mitsubishi Electric. BellSouth Cellular Corp. distributed the Simon Personal Communicator in the United States between August 1994 and February 1995, selling 50,000 units. The Simon Personal Communicator was the first personal digital assistant or PDA to include telephony features. The battery lasted only an hour, and flip phones became increasingly slim which led to its demise.

FedNow is an instant payment service developed by the Federal Reserve for depository institutions in the United States, which allows individuals and businesses to send and receive money. The service launched on July 20, 2023. Banks will be able to build products on top of the FedNow platform.

🔗 Finance & Investment 🔗 China 🔗 Economics

Zhima Credit (Chinese: 芝麻信用; pinyin: Zhīma Xìnyòng), also known as Sesame Credit, is a private credit scoring and loyalty program system developed by Ant Financial Services Group (AFSG), an affiliate of the Chinese Alibaba Group. It uses data from Alibaba's services to compile its score. Customers receive a score based on a variety of factors based on social media interactions and purchases carried out on Alibaba Group websites or paid for using its affiliate Ant Financial's Alipay mobile wallet. The rewards of having a high score include easier access to loans from Ant Financial and having a more trustworthy profile on e-commerce sites within the Alibaba Group.