Have you ever found out that something you remember from your youth is now gone, and you didn’t even notice? If you are a certain age, you might feel that way when I deliver the news: You haven’t been able to buy International Reply Coupons (IRCs) at a US Post Office since early 2013. By the end of 2026, you won’t be able to buy them anywhere. The age of the IRC is over.
What’s an IRC?
An IRC from 1978 (public domain).
If that didn’t mean anything to you, you might be too young to remember, or maybe you just weren’t into shortwave listening or ham radio. Although there were other reasons to get IRCs, a radio hobby is the most likely reason a Hackday reader would have bought an IRC.
For radio purposes, here’s the problem. You’ve worked on your station for months, and one winter night, you finally pull in that rare station from Luxembourg. They’ll send you a QSL card to verify that you heard them. You only have to send them a letter telling them what time you heard them, what frequency, and some details about the program you heard. But they probably don’t want to pay the postage required to send hundreds or thousands of cards overseas.
While this is a radio-specific problem, you might find the same issue with pen pals or when trying to buy things from an overseas company.
SASE
If everyone were in the same country, the solution would be easy. Take a stamp, put it on an envelope that has your address on it, and stuff it in with the letter. Or, you could just drop a stamp or two in the letter you sent.
The problem is, US postage won’t help Radio Luxembourg. On the other hand, the effort required for you to buy postage that works in Luxembourg would have been a nightmare.
Enter the UPU
The Universal Postal Union is a UN agency that is effectively an association of post offices in 192 countries. Their charter is to facilitate mailing things worldwide.
The IRCs date back to 1906. The idea is you buy an IRC at your post office. You send it to Radio Luxembourg, or wherever. There, the mail person at the radio station could go to their post office and trade the coupon for enough local postage to send a surface letter worldwide.
Slow Death
A more recent IRC (UPU).
As demand has dwindled, post offices worldwide have quit selling IRCs. As of last year, Australia still did. But Germany, Britain, the United States, and many other countries gave up on them long ago. In fact, Britain’s Royal Mail claimed that the average post office sold less than one IRC per year at the time it threw in the towel.
UPU decided to end IRCs altogether by December 31, 2026. The end of an era and, apparently, not just for radio hobbyists. It is telling that the UPU’s recent editions of IRCs had print runs of 1,000 or even 500. So they obviously weren’t selling very many.
IRCs Other Claim to Fame
If you’ve heard of these before and you aren’t interested in radio, then it might have been in economic history. Have you heard of the Ponzi scheme? It has become a generic term for any business scheme that relies on raising money from new investors to service debt owed to old investors.
However, the original Ponzi scheme dates back to 1920, when Charles Ponzi realized he could buy IRCs in a country where they were cheap and sell them for more in another country. He was happy to accept investors, of course.
The problem is that profits are thin, and the costs of acquiring and transporting large numbers of IRCs quickly swamp most potential profits. Fluctuations in currency exchange rates take the rest.
Goodbye!
So the end of the IRC marks a closed chapter for ham radio and swindling. There were probably other uses, too, that are now consumed by electronic mail, payment systems, and the like.
You have to wonder what adventures IRCs went on during their global travels. The video below shows one’s story.
The 7,000-year-old fish traps represent the first known evidence that humans were responsible for an unlikely population of brown trout in the mountains.
While people think of Linux as a modern operating system, it embodies ideas that are more than 50 years old. Here are some of the oldest ideas and why they stick around in modern Linux distros.
A dried-out felt-tip marker and a snapped-off piece of molded black plastic sold for $857,600 at a Sotheby's auction on Wednesday.
What otherwise might have been worthless bits of trash commanded the highest bids due to where the two items were 57 years ago—lifting off aboard NASA's Apollo 11 spacecraft on humanity's first mission to land astronauts on the Moon. More than flown odds and ends, one was the problem that almost stranded Neil Armstrong and Buzz Aldrin on the lunar surface, and the other was the simple solution to saving the mission.
"Houston, Tranquility. Do you have a way of showing the configuration of the engine arm circuit breaker?" radioed Aldrin to Mission Control after realizing he or Armstrong had inadvertently broken off the top of the circuit breaker switch that would enable their ascent engine to ignite, beginning their trip back to Earth. "The reason I'm asking is because the end of it appears to be broken off. I think we can push it back in again. I'm not sure we could pull it out if we pushed it in, though."
The lifelike avatar of President Theodore Roosevelt, which relies on artificial intelligence to answer visitors’ questions, at the Theodore Roosevelt Presidential Library in Medora, N.D. (Theodore Roosevelt Presidential Library Photo via Microsoft)
“Speak softly and carry a big prompt.”
That’s not exactly how Theodore Roosevelt put it, but presidential historian Doris Kearns Goodwin found herself face to face with an AI-powered version of the 26th president at the newly opened Theodore Roosevelt Presidential Library in Medora, N.D. — and she had questions.
Goodwin is among the high-profile visitors to interact with the lifelike, immersive version of Roosevelt that is able to discuss his life, leadership and legacy.
A week after a visit from President Trump, Goodwin joined Microsoft President Brad Smith at the library to learn how the tech giant’s AI is being used to help the institution — and the Roosevelt avatar — speak directly to future generations.
“Who better to put our avatar to the test than American historian Doris Kearns Goodwin,” Smith wrote on LinkedIn on Sunday, where he shared a video of a clearly giddy Goodwin meeting the digital Roosevelt.
“I’ve been wanting to meet you for such a long time,” Goodwin said. “I feel like I’ve lived with you for 10 years of my life when I wrote a first book about you.”
Goodwin asked Roosevelt questions about his relationship with JP Morgan, the changing will of the country, and how it was presumed that when he neared death, Roosevelt would still be fighting and still be in the arena.
“I never cared how’d I’d be remembered by the historians,” the avatar said. “Still swinging, still loud, still on your feet. If folks say I managed that, well, I’m glad of it.”
A Pulitzer Prize-winning biographer who has written extensively about presidents and American history, Goodwin was moved by the interaction.
“Wow,” she said. “It’s amazing.”
The AI works as part of Box 1, the knowledge base backbone of the museum, powered by technology Microsoft helped create. According to a July 1 Microsoft blog post, the system is loaded with hundreds of thousands of archival documents, and AI is used to “organize, enrich and reconstruct fragmented materials into searchable, contextualized historical records.”
Box 1 and AI also power The Campfire Reading Room, a digital research tool that anyone anywhere in the world can use to search through Roosevelt’s writings, letters, images and historical materials.
Microsoft donated much of its work with the library through its AI for Good Lab. The company said it plans to release a paper documenting exactly how the technology works and to open source the software used in the project.
As technology evolves, the library will evolve with it, Microsoft said. When more documents are added to Box 1 or as generative AI improves, the Roosevelt avatar will automatically update with the additional context.
“That’s why we call it a living library,” said Laura Hoffman, senior director of the AI for Good Lab. “One of the most challenging things for cultural institutions is to continue to keep their experiences feeling relevant and fresh. This is what’s great about AI technology: It will continue to get better and better.”
[Irving John Good] was at Trinity College, Oxford back in 1964. His paper, “Speculations Concerning the First Ultraintelligent Machine” could have been a topic for today, as we deal with machines that aren’t really ultraintelligent, but appear smart and think they are even smarter. He starts off with a bold thesis: “The survival of man depends on the early construction of an ultraintelligent machine.”
He also admits that we’ll need to understand more about the human brain and human thought to make a breakthrough. This is still true today. However, we still don’t fully understand how our brains work, but it seems unlikely that we are just super-large LLMs. Not that [Good] anticipated the modern chatbot. Perhaps his comments will apply more to a future AI software that actually thinks like a human, if there will ever be such a thing.
Then again, there are many parallels. One theme in the paper is that a smart machine will design a smarter machine. Unless, of course, it is afraid of being replaced. If a machine were actually sentient, what are the ethics of turning it off and tearing it apart?
It is hard to be a visionary. [Good] remarks that by 1980, progress in human/computer symbiosis will encourage more investment in the field and that by that time, there would be “great advances in microminiaturization” and “frequencies of one billion pulses per second,” might be common in “large computers.”
Back in 2024, we reported on the discovery of the Quest shipwreck, the polar exploration vessel that served Arctic explorer Sir Ernest Shackleton on his last voyage. Shackleton died before reaching their destination, and the ship sank in 1962. The Royal Canadian Geographic Society (RCGS) has now released the first images of the wreck more than 60 years after it sank, published in Canadian Geographic magazine.
Shackleton, of course, is most famous for his ill-fated voyage on the Endurance, which became trapped in sea ice in 1914 and sank. Shackleton and his crew defied the odds and survived. (The Endurance shipwreck was finally found in 2022.) By the time Shackleton returned to England, the country was embroiled in World War I, and many of his men enlisted. Shackleton was considered too old for active service. He was also deeply in debt from the Endurance expedition, earning a living on the lecture circuit. But he still dreamed of making another expedition to the Arctic Ocean north of Alaska to explore the Beaufort Sea. He got funding from an old school chum, John Quillier Rowett.
Shackleton purchased a wooden Norwegian whaler, Foca I, which his wife Emily renamed Quest. When the Canadian government withdrew its support, the mission shifted back to the Antarctic, and the Quest received an extensive retrofit. The improvements included a new deckhouse, a heated crow’s nest, a wireless set, and an odograph for tracing and charting the route automatically, as well as a Lucas deep-sea sounding machine, a large and pricey collection of cameras and photographic equipment, and even a small airplane.
Wally Funk, who in 2021 became the oldest woman to fly into space—60 years after she and 12 other women sought the same opportunity as NASA's original astronauts—died on Wednesday at 87 years old.
Funk was the last living member of the First Lady Astronaut Trainees (FLATs, or as they were later dubbed by the media, the Mercury 13), a group of women pilots who volunteered to go through the same physical and psychological tests as the United States' first spacemen.
Despite performing as well or better than their male counterparts, though, the Lovelace Woman in Space Program was conducted separately from NASA, and the space agency required that its astronauts be test pilots with jet time. The US military, however, did not accept women into its flight programs.
How old is the seven-segment display? Surely it is a product of the 1970s. After all, calculators started showing up, and the height of junior high humor was plugging 7734 into your calculator and showing it to someone upside down. Of course, for it to go mainstream, maybe they really originated in the 1960s, but no earlier than that, right? Actually, no. Sure, the LED seven-segment display had to wait for LEDs. But the actual idea is much older than that.
The concept of building numbers from a small set of reusable segments predates LED displays by decades. In fact, the basic idea appears in patents from the early 1900s and may have roots in even older mechanical signs and printing techniques.
The history isn’t entirely straightforward. Unlike vacuum tubes or transistors, segmented displays evolved gradually through a series of practical ideas rather than one defining invention.
Blacking out the Eight
While looking into the history of segmented displays, I was reminded of something I’d seen years ago in retail stores: reusable price tags printed with rows of eights.
Rather than printing every possible price, the clerk simply used a marker to black out portions of each figure, transforming an 8 into whatever digit was needed. Cover a few strokes, and the eight becomes a three. Remove a different set, and it becomes a zero or a five. It was, in essence, a manual segmented display.
Finding the exact origin of these price tags is akin to finding out where Romans bought sponges. They were inexpensive commercial supplies, not the sort of products that historians carefully documented. My recollection is from the middle of the twentieth century, but the underlying concept is almost certainly older.
Everything New is Old Again
George Mason’s 1898 21-segment display used 21 lamps and a complicated switch to display any digit or letter in a very stylish font. You can see a modern recreation of these ancient displays in the video below. While this is the basic idea, certainly, it is more ambitious than a simple 7-segment display.
I couldn’t determine that Mason’s displays were ever used for anything.
You could argue that an early 1903 invention by Carl Kinsley to draw characters telegraphically using six pens was an even better precursor, but using magnets to draw with pens on tapes hardly seems to qualify as a display, although figure 12 in the patent clearly shows the formation of numbers and even letters with this arrangement.
Digits of Patent
The direct parent of modern segmented digit displays appeared in the early 1900s (filed 1908; granted in 1910). Technically, this was an 8-segment display because it had a bar dedicated to forming a proper four, with the top-left part slanted. But removing that one segment is just an optimization. It may or may not have been the first, but by 1910, seven-segment displays were in use and not just curiosities on a workbench or dreams in a patent application.
Even for lit-up displays, the first implementations weren’t LEDs. Early displays used incandescent lamps or neon-filled tubes. By the 1930s and 1940s, segmented neon or incandescent indicators were appearing in industrial equipment and counters, instead of the common columns of ten neon bulbs, pointers, or rotating wheels.
Then, too, there were different approaches. Nixie tubes used individual character forms that lit up. Decatrons could count with ten different glowing points, each representing a digit.
Enter the LED
The real explosion came in the late 1960s when practical LED displays arrived. Suddenly, segmented displays could be compact, rugged, inexpensive, and operate at low voltages. Calculators, clocks, frequency counters, digital multimeters, and every imaginable piece of consumer electronics adopted them almost overnight.
Of course, it wasn’t just LEDs. Numitrons used seven tiny incandescent filaments. Vacuum fluorescent displays used segments with phosphor that glowed when excited. LCDs adopted the same pattern, blocking or passing light to produce the segments. But the key idea was something that lights up, arranged in seven segments.
Radio Shack’s 1976 catalog featured magnified LED displays.
Early LED displays often had all the diodes on a single die to reduce cost. That made them very tiny. It wasn’t unusual to see displays with magnifying bubbles to make it easier to read.
The important point isn’t whether they used exactly seven segments. Many didn’t. Some divided the numerals differently or used additional pieces to produce more attractive typography. The insight was the same: begin with the most complex digit and selectively remove strokes to create all the others.
Why Seven?
One of the reasons seven segments became the standard is that they strike a perfect balance (although not everyone agrees, as you can see in the video below). With fewer than seven elements, several decimal digits become difficult to distinguish. Adding more segments certainly improves appearance, but every additional segment increases wiring, decoding logic, manufacturing cost, and the number of possible failure points. Seven is the right number for — um — numbers. But what about letters?
You can make some compromises to show some letters. For example, old computers would display hex digits using seven segments, but the A would be uppercase and the B would be lowercase. You also had to light the top segment for the 6 to make it look different from a B. But you only need A-F for hex. If you need, say, the letter S, there’s no real way to make it not look like a 5 with 7 segments. But sometimes, the letters you can make are good enough.
There were also 8- and 9-segment displays that could do better with letters and special characters. You can increase the segments further to get more glyphs.
The Union Jack
Different segment counts for displays (public domain by [errorage])The solution for full letter displays was to add more segments. Despite Mason, you didn’t really need 21. By the 1970s, fourteen-segment and sixteen-segment displays had become common in instruments, telephones, calculators, and video cassette recorders. Their pattern of diagonals and crossbars earned them the nickname “Union Jack” display because the arrangement resembles the British flag. These are also sometimes called starburst displays. You occasionally see 16-segment displays, too.
Even Today
Today, you have a plethora of options for adding alphanumeric screens to just about anything. Yet, you still see 7-segment displays hanging around.
The seven-segment display isn’t successful because it’s beautiful. It isn’t even especially flexible. It’s successful because it’s close to the minimum solution that works. It delivers readable numbers with very little hardware, whether the technology behind it is incandescent bulbs, neon, vacuum fluorescence, LEDs, LCDs, or even ink on a printed price tag.
Perhaps that’s why it has survived every technological transition for more than a hundred years. Good engineering ideas often outlive the technologies that first bring them to life.
And once you start looking for segmented displays, you’ll notice they’ve been hiding in plain sight for much longer than the digital age.
Did you know that the space shuttle once launched the Statue of Liberty into space?
In fact, there were two "Lady Liberties" on board Discovery when it lifted off on its fourth flight in April 1985. To be fair, each statue was only 15 inches tall (38.1 centimeters), but they were also each made of copper that was removed from the full-size statue during its then-still-ongoing restoration.
After the weeklong STS-51D mission was over, one of the space-flown statues was placed on display, and the other was melted down to create copper seals, which were then sold to the public by the Statue of Liberty Ellis Island Centennial Commission.
While the original name of what much of the world knows as the NES was the Nintendo Family Computer, or Famicom for short, it was very rarely used as a family computer. Sure, there was a basic cartridge and an add-on keyboard sold in Japan, but it was always a sideshow to the games.
Nintendo recognized that when they brought their Entertainment System overseas. Most of the various famiclones — which date back to the mid-80s — are the same. BIT in Taiwan had a different idea: their Bit 79 would be a full home computer. Picture a C=64 that plays Nintendo games, and you might not be too far off. [Inkbox] tells the full story in his latest YouTube video, and it’s a must-watch for anyone interested in the history of 8-bit machines that are totally unknown in the West.
BIT were both game makers and system cloners; you may even have seen one of their NES or Atari games, as they were exported widely. By 1989 they’d already gone through a surprising number of Famicom clones, but those were pure clones and just played games. The Bit79 is obviously different — for one, it’s got a built-in keyboard in a wedge case. Apparently a pretty good one at that. For another, it starts with a bootloader that lets you choose between BASIC on ROM and loading the cartridge. For a third, it’s got a full 8K of RAM, quadrupling the Famicom’s offering– plus an additional 2K for the PPU, in what you might consider an early example of video RAM. Both CPU and PPU are knockoff chips made in Taiwan by UMC. The system even has what looks like a DB25 connect a printer. There’s also an expansion port, but no evidence that add-ons were ever sold, despite reports of a 64K memory add-on.
Back to the BASIC ROM for a moment– it’s not Famicom BASIC, as was clear in the manuals. [Inkbox] dumped the ROM to find that it is actually AppleSoft BASIC, of all things. That’s not only an odd bit of piracy, it’s also a big miss, since Apple’s BASIC doesn’t have any commands to make use of the PPU the way Famicom’s version does. POKING the registers during the vBlank interval is apparently not an easy thing to do. Perhaps that’s why we’ve never heard of this machine — well, that, and the fact we’re not located in East Asia where it was sold.
While the Bit79 didn’t sell particularly well, apparently it inspired a whole wave of “educational computer” famiclones in 1990s China that are largely unknown to the English-speaking world, making it an important part of computer history.
While BIT Corp is long gone, if you want to play around with their great experiment in turning a famiclone into a home computer, an emulator is available online, and the ROMs are preserved on the Internet Archive thanks to [InkBox].
The Apollo 11 astronaut had already beaten the original schedule for the opening of the National Air and Space Museum by three days, but no one would remember that if these final 36 minutes didn't go perfectly.
President Gerald Ford and Vice President Nelson Rockefeller took 35 seconds to find their seats on the red, white, and blue bunting-lined outdoor stage. The flyover by the Thunderbirds was quick enough. At any other event, it would have been the only time-dependent concern of the day.
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