Within the retro computing community there exists a lot of controversy about so-called ‘retrobrighting’, which involves methods that seeks to reverse the yellowing that many plastics suffer over time. While some are all in on this practice that restores yellow plastics to their previous white luster, others actively warn against it after bad experiences, such as [Tech Tangents] in a recent video.
Uneven yellowing on North American SNES console. (Credit: Vintage Computing)
After a decade of trying out various retrobrighting methods, he found for example that a Sega Dreamcast shell which he treated with hydrogen peroxide ten years ago actually yellowed faster than the untreated plastic right beside it. Similarly, the use of ozone as another way to achieve the oxidation of the brominated flame retardants that are said to underlie the yellowing was also attempted, with highly dubious results.
While streaking after retrobrighting with hydrogen peroxide can be attributed to an uneven application of the compound, there are many reports of the treatment damaging the plastics and making it brittle. Considering the uneven yellowing of e.g. Super Nintendo consoles, the cause of the yellowing is also not just photo-oxidation caused by UV exposure, but seems to be related to heat exposure and the exact amount of flame retardants mixed in with the plastic, as well as potentially general degradation of the plastic’s polymers.
Pending more research on the topic, the use of retrobrighting should perhaps not be banished completely. But considering the damage that we may be doing to potentially historical artifacts, it would behoove us to at least take a step or two back and consider the urgency of retrobrighting today instead of in the future with a better understanding of the implications.
Ever heard of MUMPS? Both programming language and database, it was developed in the 1960s for the Massachusetts General Hospital. The goal was to streamline the increasingly enormous timesink that information and records management had become, a problem that was certain to grow unless something was done. Far from being some historical footnote, MUMPS (Massachusetts General Hospital Utility Multi-Programming System) grew to be used by a wide variety of healthcare facilities and still runs today. If you’ve never heard of it, you’re in luck because [Asianometry] has a documentary video that’ll tell you everything.
MUMPS had rough beginnings but ultimately found widespread support and use that continues to this day. As a programming language, MUMPS (also known simply as “M”) has the unusual feature of very tight integration with the database end of things. That makes sense in light of the fact that it was created to streamline the gathering, processing, and updating of medical data in a busy, multi-user healthcare environment that churned along twenty-four hours per day.
It may show its age (the term “archaic” — among others — gets used when it’s brought up) but it is extremely good at what it does and has a proven track record in the health care industry. This, combined with the fact that efforts to move to newer electronic record systems always seem to find the job harder than expected, have helped keep it relevant. Have you ever used MUMPS? Let us know in the comments!
The Sharp PC-G801 was an impressive little pocket computer when it debuted in 1988. However, in the year 2025, a Z80-compatible machine with just 8 kB of RAM is hardly much to get excited about. [shiura] decided to take one of these old machines and upgrade it into something more modern and useful.
The build maintains the best parts of the Sharp design — namely, the case and the keypad. The original circuit board has been entirely ripped out, and a custom PCB was designed to interface with the membrane keypad and host the new internals. [shiura] landed on the Raspberry Pi Zero 2W to run the show. It’s a capable machine that runs Linux rather well and has wireless connectivity out of the box. It’s paired with an ESP32-S3 microcontroller that handles interfacing all the various parts of the original Sharp hardware. It also handles the connection to the 256×64 OLED display. The new setup can run in ESP32-only mode, where it acts as a classic RPN-style calculator. Alternatively, the Pi Zero can be powered up for a full-fat computing experience.
An interesting trend over the last year or two has been the emergence of modern retrocomputer PCs, recreations of classic PC hardware from back in the day taking advantage of modern parts alongside the venerable processors. These machines are usually very well specified for a PC from the 1980s, and represent a credible way to run your DOS or early Windows software on something close to the original. [CNX Software] has news of a couple of new ones from the same manufacturer in China, one sporting a 386sx and the other claiming it can take either an 8088 or an 8086.
Both machines use the same see-through plastic case, screen, and keyboard, and there are plenty of pictures to examine the motherboard. There are even downloadable design files, which is an interesting development. They come with a removable though proprietary looking VGA card bearing a Tseng Labs ET4000, a CF card interface, a USB port which claims to support disk drives, a sound card, the usual array of ports, and an ISA expansion for which a dock is sold separately. The battery appears to be a LiPo pouch cell of some kind.
If you would like one they can be found through the usual channels for a not-outrageous price compared to similar machines. We can see the attraction, though maybe we’ll stick with an emulator for now. If you’d like to check out alternatives we’ve reported in the past on similar 8088 and 386sx computers.
The BBC wanted to show everyone how a computer might be used in schools. A program aired in 1979 asks, “Will Computers Revolutionise Education?” There’s vintage hardware and an appearance of PILOT, made for computer instructions.
Using PILOT looks suspiciously like working with a modern chatbot without as much AI noise. The French teacher in the video likes that schoolboys were practicing their French verb conjugation on the computer instead of playing football.
If you want a better look at hardware, around the five-minute mark, you see schoolkids making printed circuit boards, and some truly vintage oscilloscope close-ups. There are plenty of tiny monitors and large, noisy printing terminals.
You have to wonder where the eight-year-olds who learned about computers in the video are today, and what kind of computer they have. They learned binary and the Towers of Hanoi. Their teacher said the kids now knew more about computers than their parents did.
As a future prediction, [James Bellini] did pretty well. Like many forecasters, he almost didn’t go far enough, as we look back almost 50 years. Sure, Prestel didn’t work out as well as they thought, dying in 1994. But he shouldn’t feel bad. Predicting the future is tough. Unless, of course, you are [Arthur C. Clarke].
You have that slide rule in the back of the closet. Maybe it was from your college days. Maybe it was your Dad’s. Honestly. Do you know how to use it? Really? All the scales? That’s what we thought. [Amen Zwa, Esq.] not only tells you how slide rules came about, but also how to use many of the common scales. You can also see his collection and notes on being a casual slide rule collector and even a few maintenance tips.
The idea behind these computing devices is devilishly simple. It is well known that you can reduce a multiplication operation to addition if you have a table of logarithms. You simply take the log of both operands and add them. Then you do a reverse lookup in the table to get the answer.
For a simple example, you know the (base 10) log of 10 is 1 and the log of 1000 is 3. Adding those gives you 4, and, what do you know, 104 is 10,000, the correct answer. That’s easy when you are working with numbers like 10 and 1000 with base 10 logarithms, but it works with any base and with any wacky numbers you want to multiply.
The slide rule is essentially a log table on a stick. That’s how the most common scales work, at least. Many rules have other scales, so you can quickly, say, square or cube numbers (or find roots). Some specialized rules have scales for things like computing power.
We collect slide rules, too. Even oddball ones. We’ve often said that the barrier of learning to use a slide rule weeded out many bad engineers early.
When people talk about the lack of a DOOM being the doom Commodore home computers, they aren’t talking about the C64, which was deep into obsolescence when demon-slaying suddenly became the minimal requirement for all computing devices. That didn’t stop [Kamil Wolnikowski] and [Piotr Kózka] from hacking together Greya ray-cast first-person shooter for the Commodore 64.
Grey bares more than a passing resemblance to id-software’s most-ported project. It apparently runs at 16 frames per second on a vanilla C64 — no super CPU required. The secret to the speedy game play is the engine’s clever use of the system’s color mapping functionality: updating color maps is faster than redrawing the screen. Yeah, that makes for rather “blockier” graphics than DOOM, but this is running on a Commodore 64, not a 386 with 4 MB of RAM. Allowances must be made. Come to think of it, we don’t recall DOOM running this smooth on the minimum required hardware — check out the demo video below and let us know what you think.
Since the dawn of computers, we’ve tried different ways to store data. These days, you grab data over the network, but you probably remember using optical disks, floppies, or, more recently, flash drives to load something into your computer. Old computers had to use a variety of methods, such as magnetic tape. But many early computers used some technology that existed from the pre-computer era, like punched cards or, as [Anthony Francis-Jones] shows us, paper tape.
Paper tape was common in TeleType machines and some industrial applications. In fact, as early as 1725, looms could use paper tape, which would eventually lead to punched cards. For computers, there were two common variations that differed in how many holes were punched across the tape: 5 or 8. There was also a small sprocket hole that allowed a gear to move the tape forward through a reader.
Typically, brushes or optical sensors would read the holes into the computer. Some paper tape used regular paper, but others used oily paper. You could also get tapes made out of mylar, which was very durable.
The other big difference in tapes was in how they were punched. A conventional tape had the entire hole punched out, leaving confetti-like “chad.” There were also chadless tapes where the chad was left slightly connected to the paper.
One common feature of paper tape was that it would skip any section where every hole had been punched. This allowed you to erase parts of the tape by punching over it. Then, with scissors and tape, you could splice sections by lining up the fully punched areas between two sections of tape. You could also make endless loops of tape.
There’s a tactile joy to the humble 3.5″ floppy that no USB stick will ever match. It’s not just the way they thunk into place in a well-made drive, the eject button, too, is a tactile experience not to be missed. If you were a child in disk-drive days, you may have popped a disk in-and-out repeatedly just for the fun of it — and if you weren’t a child, and did it anyway, we’re not going to judge. [igor] has come up with a physical game called “Floppy Flopper” that provides an excuse to do just that en masse, and it looks like lots of fun.
It consists of nine working floppy drives in a 3×3 grid, all mounted on a hefty welded-steel frame. Each drive has an RGB LED above it. The name of the game is to swap floppies as quickly as possible so that the color of the floppy in the drive matches the color flashing above it. Each successful insertion is worth thirteen points, tracked on a lovely matrix display. Each round is faster than the last, until you miss the window or mix up colors in haste. That might make more sense if you watch the demo video below.
[igor] could have easily faked this with NFC tags, as we’ve seen floppy-like interfaces do, or perhaps just use a color sensor. But no, those nine drives are all in working order. In the interest of speed — this is a timed challenge, after all, and we don’t need a PC slowing it down — each floppy is given its own microcontroller. Rather than reading data off the disk, only the disk’s write-protect and density holes are checked. He’s only using R, G, and B for floppy colors, so those four bits are enough. Unfortunately [igor]’s collection of floppies is very professional — lots of black and grey — so he needed to use colored stickers instead of technicolor plastic.
The project is open source, if you happen to have a stack of floppy drives of your own. If you don’t, but still want to play, the area, the Floppy Flopper is being exhibited at RADIONA in Rijeka, Croatia until December 5th 2025. If you happen to be in the neighborhood, it might be worth a trip.
If we had a nickle for every physical game that used a floppy drive, we’d have two nickles just this year. Which isn’t a lot, but it’s kind of neat to see so long after the last diskettes came off the production lines.
I’m sitting in front of an old Sayno Plasma TV as I write this on my media PC. It’s not a productivity machine, by any means, but the screen has the resolution to do it so I started this document to prove a point. That point? Plasma TVs are awesome.
Always the Bridesmaid, Never the Bride
An Egyptian god might see pixels on an 8K panel, but we puny mortals won’t. Image “Horus Eye 2” by [Jeff Dahl]The full-colour plasma screens that were used as TVs in the 2000s are an awkward technological cul-de-sac. Everyone knows and loves CRTs for the obvious benefits they offer– bright colours, low latency, and scanlines to properly blur pixel art. Modern OLEDs have more resolution than the Eye of Horus, never mind your puny human orbs, and barely sip power compared to their forbearers. Plasma, though? Not old enough to be retro-cool, not new enough to be high-tech, plasma displays are sadly forgotten.
It’s funny, because I firmly believe that without plasma displays, CRTs would have never gone away. Perhaps for that I should hate them, but it’s for the very reasons that Plasma won out over HD-CRTs in the market place that I love them.
What You Get When You Get a Plasma TV
I didn’t used to love Plasma TVs. Until a few years ago, I thought of them like you probably do: clunky, heavy, power-hungry, first-gen flatscreens that were properly consigned to the dustbin of history. Then I bought a house.
The house came with a free TV– a big plasma display in the basement. It was left there for two reasons: it was worthless on the open market and it weighed a tonne. I could take it off the wall by myself, but I could feel the ghost of OSHA past frowning at me when I did. Hauling it up the stairs? Yeah, I’d need a buddy for that… and it was 2020. By the time I was organizing the basement, we’d just gone into lockdown, and buddies were hard to come by. So I put it back on the wall, plugged in my laptop, and turned it on.
I was gobsmacked. It looked exactly like a CRT– a giant, totally flat CRT in glorious 1080p. When I stepped to the side, it struck me again: like a CRT, the viewing angle is “yes”.
How it Works
None of this should have come as a surprise, because I know how a Plasma TV works. I’d just forgotten how good they are. See, a Plasma TV really was an attempt to get all that CRT goodness in a flat screen, and the engineers at Fujitsu, and later elsewhere, really pulled it off.
Like CRTs, you’ve got phosphors excited to produce points of light to create an image– and only when excited, so the blacks are as black as they get. The phosphors are chemically different from those in CRTs but they come in similar colours, so colours on old games and cartoons look right in a way they don’t even on my MacBook’s retina display.
Unlike a CRT, there’s no electron beam scanning the screen, and no shadow mask. Instead, the screen is subdivided into individual pixels inside the flat vacuum panel. The pixels are individually addressed and zapped on and off by an electric current. Unlike a CRT or SED, the voltage here isn’t high enough to generate an electron beam to excite the phosphors; instead the gas discharge inside the display emits enough UV light to do the same job.
Each phosphor-filled pixel glows with its own glorious light thanks to the UV from gas discharge in the cell. Image based on “Plasma-Display-Composition.svg” by [Jari Laamanen].Still, if it feels like a CRT, and that’s because the subpixels are individual blobs of phosphors, excited from behind, and generating their own glorious light.
It’s Not the Same, Though
It’s not a CRT, of course. The biggest difference is that it’s a fixed-pixel display, with all that comes with that. This particular TV has all the ports on the back to make it great for retrogaming, but the NES, or what have you, signal still has to be digitally upscaled to match the resolution. Pixel art goes unblurred by scanlines unless I add it in via emulation, so despite the colour and contrast, it’s not quite the authentic experience.
For some things, like the Atari 2600, the scanline blur really doesn’t matter. Image: “Atari 2600 on my 42 inch plasma TV” by [Jeffisageek] The built-in upscaling doesn’t introduce enough latency for a filthy casual like me to notice, but I’ll never be able to play Duck Hunt on the big screen unless I fake it with a Wii. Apparently some Plasma TVs are awesome for latency on the analog inputs, and others are not much better than an equivalent-era LCD. There’s a reason serious retro gamers pay serious money for big CRTs.
Those big CRTs don’t have to worry about burn in, either, something I have been very careful in the five years I’ve owned this second-hand plasma display to avoid. I can’t remember thinking much about burn-in with CRTs since we retired the amber-phosphor monitor plugged into the Hercules Graphics card on our family’s 286 PC.
The dreaded specter of burn-in is plasma’s Achilles heel – more than the weight and thickness, which were getting much better before LG pulled the plug as the last company to exit this space, or the Energy Star ratings, which weren’t going to catch up to LED-backlit LCDs, but had improved as well. The fear of burn-in made you skip the plasma, especially for console gaming.
This screen is haunted by the ghost of CNN’s old logo. Burning in game graphics was less common but more fun. Ironically, it’s an LCD. Image: “logo of CNN burnt on a screen” by [Nate]Early plasma displays could permanently damage the delicate phosphors in only a handful of hours. That damage burnt the unmoving parts of an image permanently into the phosphors in the form of “ghosting”, and unless you caught it early, it was generally not repairable. The ghosting issue got better over time, but the technology never escaped the stigma, and the problem never entirely went away. If that meant that after a marathon Call-of-Duty session the rest of the family had to stare at your HUD on every movie night, Dad wasn’t going to buy another plasma display.
By the end, the phosphors improved and various tricks like jiggling the image pixel-by-pixel were found to avoid burn-in, and it seems to have worked: there’s absolutely no ghosting on my model, and you can sometimes find late-model Plasma TVs for the low, low cost of “get this thing off my wall and up the stairs” that are equally un-haunted. I may grab another, even if I have to pay for it. It’s a lot easier to hide a spare flatscreen than an extra CRT, another advantage to the plasma TVs, and in no case do phosphors last forever.
In the mean time, I’m going to enjoy the contrast ratio, refresh rate, and the bonus space heater. I’m in Canada, and winter is coming, so it’s hard to get too overworked about waste heat when there’s frost on your windowpanes.
[Usagi Electric] is known for minicomputers, but in a recent video, he shows off his TMS9900-based homebrew computer. The TMS9900 CPU was an early 16-bit CPU famously used in the old TI-99/4A computer, but as the video points out, it wasn’t put to particularly good use in the TI-99/4A because its RAM was hidden behind an inefficient interface and it didn’t leverage its 16-bit address space.
The plan is for this computer to have 2K words of ROM, 6K words of RAM, and three serial lines: one for the console terminal, another for a second user console terminal, and the third for access to a tape drive.
In the video, [Usagi Electric] spends a fair bit of time making the rack-mount casing for his computer and its two power supplies. The UART for 300-baud terminal access is currently in breadboard format, but it is set up to transmit and is functional so far! Up next will be support for receiving. The UART he’s using is the TR1602B, and he spends some time reviewing its datasheet in this video.
Though mobile devices and Apple Silicon have seen ARM-64 explode across the world, there’s still decent odds you’re reading this on a device with an x86 processor — the direct descendant of the world’s first civilian microprocessor, the Intel 4004. The 4004 wasn’t much good on its own, however, which is why [Klaus Scheffler] and [Lajos Kintli] have produced super-sized discrete chips of the 4001 ROM, 4002 RAM, and 4003 shift register to replicate a 1970s calculator at 10x the size and double the speed, all in time for the 4004’s 50th anniversary.
We featured this project a couple of years back, when it was just a lonely microprocessor. Adding the other MSC-4 series chips enabled the pair to faithfully reproduce the logic of a Busicom 141-PF calculator, the very first to market with Intel’s now-legendary microprocessor. Indeed, this calculator is the raison d’etre for the 4004: Busicom commissioned the whole Micro-Computer System 4-bit (MCS-4) set of chips specifically for this calculator. Only later, once they realized what they had made, did Intel buy the rights back from the Japanese calculator company, and the rest, as they say, is history.
Since its history, it belongs in a museum– and that’s where this giant, FET-based calculator is going. If you happen to be in Solothurn, Switzerland, you’ll be able to see it at a new history of technology exhibit opening at the Enter Museum in 2026. Do check out the write-up and links at 4004.com if you want to learn about this important piece of human history.
The museum-quality hack. Three 4003 shift registers are on the left, with a 4001 ROM above the 4004 CPU in the center, flanked by three 4002 RAM “chips” on the right. Photo by [Klaus Scheffler].We had to specify “first civilian microprocessor” at the start of this article because the US Navy beat them to the punch by a whole year, and kept it secret until 1998. There’s something very 1970s about the fact that top-secret US military technology was reinvented for a Japanese calculator within a year. It honestly makes [Federico Faggin], the man credited with the design, seem no less visionary than when we thought he was first out of the gate.
Amiga and Atari fans used to lord over their Apple-eating brethren the fact that Cupertino never moved to the most advanced 68k processors — so for a while, thanks to 68060 accelerator cards, the fastest thing running Macintosh software was an Amiga (or Atari). After all these years, the Macintosh community is finally getting the last laugh, as [zigzagjoe] demonstrates an actual Macintosh booting with a 68060 CPU for the first time in a thread on 68KMLA. Video or it didn’t happen? Check it out below.
The Mac in question is a Quadra 650, which is a good choice since it was about the last thing Apple sold before switching to PowerPC, and ran the 68040 processor. [Reinauer] had already produced a 68040-to-68060 socket adapter (the two chips not being pinout compatible), so the hardware part of the battle was already set. Software, however? That was a different story, and where [zigzagjoe] put in the effort.
We’re spoiled by decades of backwards compatibility in the x86 instruction set; Motorola wasn’t as kind back in the day, and the 68060 isn’t fully compatible with the earlier 68040’s instruction set. They did provide a translation that [zigzagjoe] was able to build into his custom ROM, though, which is how he’s able to get the Mac to boot and install System 7.1, the newest version that would boot.
Alas, the full 66 MHz clock speed [zigzagjoe] proved unstable. To make branch prediction work, he had to clock down to 50 MHz. Considering the ‘040 clocked at 25 MHz in the Quadra 650, that’s still a considerable improvement in clock speed.
At 66 MHz and giving up branch prediction, DOOM runs at 16.4 FPS. It slowed down (14.3 FPS) at 50 MHz, and branch prediction. We expected branching to have a greater impact, but apparently not. While DOOM is perhaps not the best benchmark on this hardware, it does answer the most important question you can ask of any bit of kit: yes, it does run DOOM!
In the days of 8-bit home computing, the more fancy machines had sound chips containing complete synthesizers, while budget machines made do with simple output ports connected to a speaker — if they had anything at all. [Normal User] appears to be chasing the later route, making PCM sound by abusing the serial port on a 6522 VIA chip.
A serial port is when you think about it, a special case of a one-bit output port. It’s designed for byte data communication but it can also carry a PCM data stream. We’ve seen this used with microcontrollers and peripherals such as the I2S port plenty of times here at Hackaday, to produce such things as NTSC video. The 1970s-spec equivalent might not be as fast as its modern equivalent, but it’s capable of delivering audio at some level. The machine in question is a Ben Eater breadboard 6502 with a World’s Worst Video Card, and as you can hear in the video below the break, it’s not doing a bad job for the era,
If you think this hack sounds a little familiar then in a sense you’re right, because Ben Eater himself made noises with a 6522. However it differs from that in that he used the on-board timers instead. After all, the “V” in “VIA” stands for “versatile”.
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