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๐ SuperH
SuperH (or SH) is a 32-bit reduced instruction set computing (RISC) instruction set architecture (ISA) developed by Hitachi and currently produced by Renesas. It is implemented by microcontrollers and microprocessors for embedded systems.
At the time of introduction, SuperH was notable for having fixed-length 16-bit instructions in spite of its 32-bit architecture. This was a novel approach; at the time, RISC processors always used an instruction size that was the same as the internal data width, typically 32-bits. Using smaller instructions had consequences, the register file was smaller and instructions were generally two-operand format. But for the market the SuperH was aimed at, this was a small price to pay for the improved memory and processor cache efficiency.
Later versions of the design, starting with SH-5, included both 16- and 32-bit instructions, with the 16-bit versions mapping onto the 32-bit version inside the CPU. This allowed the machine code to continue using the shorter instructions to save memory, while not demanding the amount of instruction decoding logic needed if they were completely separate instructions. This concept is now known as a compressed instruction set and is also used by other companies, the most notable example being ARM for its Thumb instruction set.
As of 2015, many of the original patents for the SuperH architecture are expiring and the SH-2 CPU has been reimplemented as open source hardware under the name J2.
Discussed on
- "SuperH" | 2021-12-04 | 147 Upvotes 68 Comments
๐ Electrodynamic Tether
Electrodynamic tethers (EDTs) are long conducting wires, such as one deployed from a tether satellite, which can operate on electromagnetic principles as generators, by converting their kinetic energy to electrical energy, or as motors, converting electrical energy to kinetic energy. Electric potential is generated across a conductive tether by its motion through a planet's magnetic field.
A number of missions have demonstrated electrodynamic tethers in space, most notably the TSS-1, TSS-1R, and Plasma Motor Generator (PMG) experiments.
Discussed on
- "Electrodynamic Tether" | 2021-12-04 | 83 Upvotes 8 Comments
๐ Evolved antenna
In radio communications, an evolved antenna is an antenna designed fully or substantially by an automatic computer design program that uses an evolutionary algorithm that mimics Darwinian evolution. This procedure has been used in recent years to design a few antennas for mission-critical applications involving stringent, conflicting, or unusual design requirements, such as unusual radiation patterns, for which none of the many existing antenna types are adequate.
Discussed on
- "Evolved antenna" | 2018-11-14 | 192 Upvotes 67 Comments
๐ Roland the Farter
Roland the Farter (known in contemporary records as Roland le Fartere, Roulandus le Fartere or Roland le Petour) was a medieval flatulist who lived in twelfth-century England. He was given Hemingstone manor in Suffolk and 12 hectares (30 acres) of land in return for his services as a jester for King Henry II. Each year he was obliged to perform "Unum saltum et siffletum et unum bumbulum" (one jump, one whistle, and one fart) for the King's court at Christmas.
Roland is listed in the thirteenth-century English Liber Feodorum (Book of Fees).
Discussed on
- "Roland the Farter" | 2021-11-29 | 10 Upvotes 3 Comments
๐ PiHKAL: โPhenethylamines I Have Known and Lovedโ
PiHKAL: A Chemical Love Story is a book by Dr. Alexander Shulgin and Ann Shulgin, published in 1991. The subject of the work is psychoactive phenethylamine chemical derivatives, notably those that act as psychedelics and/or empathogen-entactogens. The main title, PiHKAL, is an acronym that stands for "Phenethylamines I Have Known and Loved".
The book is arranged into two parts, the first part being a fictionalized autobiography of the couple and the second part describing 179 different psychedelic compounds (most of which Shulgin discovered himself), including detailed synthesis instructions, bioassays, dosages, and other commentary.
The second part was made freely available by Shulgin on Erowid while the first part is available only in the printed text. While the reactions described are beyond the ability of people with a basic chemistry education, some tend to emphasize techniques that do not require difficult-to-obtain chemicals. Notable among these are the use of mercury-aluminum amalgam (an unusual but easy to obtain reagent) as a reducing agent and detailed suggestions on legal plant sources of important drug precursors such as safrole.
Discussed on
- "PiHKAL: โPhenethylamines I Have Known and Lovedโ" | 2021-11-29 | 29 Upvotes 2 Comments
๐ Ebers Papyrus
The Ebers Papyrus, also known as Papyrus Ebers, is an Egyptian medical papyrus of herbal knowledge dating to circa 1550 BC. Among the oldest and most important medical papyri of ancient Egypt, it was purchased at Luxor in the winter of 1873โ74 by Georg Ebers. It is currently kept at the library of the University of Leipzig, in Germany.
Discussed on
- "Ebers Papyrus" | 2021-11-28 | 38 Upvotes 7 Comments
๐ Fragments of Olympian Gossip
"Fragments of Olympian Gossip" is a poem that Nikola Tesla composed in the late 1920s for his friend the German poet and mystic George Sylvester Viereck. It made fun of the scientific establishment of the day.
While listening on my cosmic phone
I caught words from the Olympus blown.
A newcomer was shown around;
That much I could guess, aided by sound.
"There's Archimedes with his lever
Still busy on problems as ever.
Says: matter and force are transmutable
And wrong the laws you thought immutable."
"Below, on Earth, they work at full blast
And news are coming in thick and fast.
The latest tells of a cosmic gun.
To be pelted is very poor fun.
We are wary with so much at stake,
Those beggars are a pestโno mistake."
"Too bad, Sir Isaac, they dimmed your renown
And turned your great science upside down.
Now a long haired crank, Einstein by name,
Puts on your high teaching all the blame.
Says: matter and force are transmutable
And wrong the laws you thought immutable."
"I am much too ignorant, my son,
For grasping schemes so finely spun.
My followers are of stronger mind
And I am content to stay behind,
Perhaps I failed, but I did my best,
These masters of mine may do the rest.
Come, Kelvin, I have finished my cup.
When is your friend Tesla coming up."
"Oh, quoth Kelvin, he is always late,
It would be useless to remonstrate."
Then silenceโshuffle of soft slippered feetโ
I knock andโthe bedlam of the street.
Nikola Tesla, Novice
๐ British Navy against slave trade
The British Royal Navy established the West Africa Squadron at substantial expense in 1808 after Parliament passed the Slave Trade Act of 1807, an Act for the Abolition of the Slave Trade. The squadron's task was to suppress the Atlantic slave trade by patrolling the coast of West Africa. With a home base at Portsmouth, England, it began with two small ships, the 32-gun fifth-rate frigate HMSย Solebay and the Cruizer-class brig-sloop HMSย Derwent. At the height of its operations, the squadron employed a sixth of the Royal Navy fleet and marines. In 1819 the Royal Navy established a West Coast of Africa Station and the West Africa Squadron became known as the Preventative Squadron. It remained an independent command until 1856 and then again 1866 to 1867. Between 1830 and 1865, more than 1,500 British sailors died on their mission of freeing slaves with the West Africa Squadron.
Between 1808 and 1860 the West Africa Squadron captured 1,600 slave ships and freed 150,000 Africans. It is considered the most costly international moral action in modern history.
The Squadron has been described as being poorly resourced and plagued by corruption; it only managed to capture around 6% of the transatlantic slave ships, but patrolling 3,000 miles of African coast from 1808 to 1860 it liberated 150,000 Africans.
Discussed on
- "British Navy against slave trade" | 2021-11-28 | 28 Upvotes 1 Comments
๐ Aphantasia
Aphantasia is a condition where one does not possess a functioning mind's eye and cannot voluntarily visualize imagery. The phenomenon was first described by Francis Galton in 1880 but has since remained largely unstudied. Interest in the phenomenon renewed after the publication of a study in 2015 conducted by a team led by Professor Adam Zeman of the University of Exeter, which also coined the term aphantasia. Research on the condition is still scarce.
Discussed on
- "Aphantasia - the inability to voluntarily create mental images" | 2021-11-28 | 105 Upvotes 276 Comments
- "Aphantasia" | 2019-06-24 | 85 Upvotes 72 Comments
๐ Cpuid: EAX=8FFFFFFFh: AMD Easter Egg
In the x86 architecture, the CPUID instruction (identified by a CPUID opcode) is a processor supplementary instruction (its name derived from CPU IDentification) allowing software to discover details of the processor. It was introduced by Intel in 1993 with the launch of the Pentium and SL-enhanced 486 processors.
A program can use the CPUID to determine processor type and whether features such as MMX/SSE are implemented.
Discussed on
- "Cpuid: EAX=8FFFFFFFh: AMD Easter Egg" | 2021-11-26 | 24 Upvotes 7 Comments