The Intel 8087 And Conditional Microcode Tests

January 11, 2026 by Maya Posch 2 Comments

Continuing his reverse-engineering of the Intel 8087, [Ken Shirriff] covers the conditional tests that are implemented in the microcode of this floating point processing unit (FPU). This microcode contains the details on how to perform the many types of specialized instructions, like cos and arctan, all of which decode into many microcode ops. These micro ops are executed by the microcode engine, which [Ken] will cover in more detail in an upcoming article, but which is effectively its own CPU.

Conditional instructions are implemented in hardware, integrating the states of various functional blocks across the die, ranging from the instruction decoder to a register. Here, the evaluation is performed as close as possible to the source of said parameter to save on wiring.

Implementing this circuitry are multiplexers, with an example shown in the top die shot image. Depending on the local conditions, any of four pass transistors is energized, passing through that input. Not shown in the die shot image are the inverters or buffers that are required with the use of pass transistors to amplify the signal, since pass transistors do not provide that feature.

Despite how firmly obsolete the 8087 is today, it still provides an amazing learning opportunity for anyone interested in ASIC design, which is why it’s so great that [Ken] and his fellow reverse-engineering enthusiasts keep plugging away at recovering all this knowledge.

Reverse-Engineering The Tamagotchi IR Connection

January 10, 2026 by Maya Posch 2 Comments

The Tamagotchi Connection is a series of Tamagotchi toys that took the original portable pet concept and mixed things up with a wireless connection, which allowed you to interact with the pets of other proud Tamagotchi owners. This wireless connection is implemented using an infrared transceiver, somewhat like IrDA, but as [Zach Resmer] discovered while reverse-engineering this connection, it’s actually what is called ‘Nearly NEC’ by [Natalie Silvanovich], who has a GitHub repository full of related Tamagotchi hacking tools and ROM dumps.

With the protocol figured out, creating a transceiver for low-bitrate infrared communication isn’t particularly hard. In this case, it was implemented using an RP2040 MCU and an appropriate IR LED and receiver pair. This Tamagometer project was also implemented as an app for the Flipper Zero, and a custom PCB called the Pico TamaBadge by [Daniel Weidman].

There’s a web application associated with [Zach]’s project using a Web Serial-enabled browser (i.e. Chrome). The serial protocol is somewhat documented in the patent for the device’s connection feature, which makes it relatively easy to implement yourself.

Yamato-1: The World’s First Ship With Magnetohydrodynamic Propulsion

January 10, 2026 by Maya Posch 44 Comments

Although the humble propeller and its derivatives still form the primary propulsion method for ships, this doesn’t mean that alternative methods haven’t been tried. One of the more fascinating ones is the magnetohydrodynamic drive (MHDD), which uses the Lorentz force to propel a watercraft through the water. The somewhat conductive seawater is thus the working medium, with no moving parts required.

The end of the MHD thruster from the Yamato 1. It has six smaller green tubes surrounding a central circle. All of these pieces are coming through a grey metal fixture that is a circular shape. Small labels are affixed with Japanese writing on them. It is inside a sky blue metal frame. — The end of the MHD thruster from the *Yamato-1*.

Although simple in nature, only the Japanese Yamato-1 full-scale prototype ever carried humans in 1992. As covered in a recent video by [Sails and Salvos], the prototype spent most of its time languishing at the Kobe Maritime Museum, until it was scrapped in 2016.

There are two types of MHDD, based around either conduction – involving electrodes – or induction, which uses a magnetic field. The thrusters used by the Yamato-1 used the latter type of MHDD, involving liquid helium-cooled, super-conducting coils. The seawater with its ions from the dissolved salts responds to this field by accelerating according to the well-known right-hand rule, thus providing thrust.

The main flaw with an MHDD as used by the Yamato-1 is that it’s not very efficient, with a working efficiency of about 15%, and a top speed of about 15 km/h (8 knots). Although research in MHDDs hasn’t ceased yet, the elemental problem of seawater not really being that great as the fluid without e.g. adding more ions to it has meant that ships like the Yamato-1 are likely to remain an oddity like the Lun-class ekranoplan ground effect vehicle.

For as futuristic as this technology sounds, it’s suprisingly straightforward to build a magnetohydrodynamic drive of your own in the kitchen sink. Continue reading “Yamato-1: The World’s First Ship With Magnetohydrodynamic Propulsion” →

Bose SoundTouch Smart Speakers Get An Open Source Lifeline

January 9, 2026 by Maya Posch 8 Comments

After initially announcing that Bose will completely turn off all ‘smart’ features in its SoundTouch series of speaker products, the company has seemingly responded to the wave of unhappy feedback with a compromise solution. Rather than the complete shutdown and cut-off that we reported on previously, Bose will now remove cloud support as its servers shut down, but the SoundTouch mobile app will get an update that gets truncated to just the local support functions. Bose also made the SoundTouch Web API documentation available as a PDF document.

The shutdown date has also been extended from the original February 18 to May 6th of this year. Although these changes mean that the mobile app can no longer use music services, features like grouping speakers and controlling playback will keep working. Features such as presets which were cloud-based will naturally stop working.

With the web API documentation made public it remains to be seen how helpful this will be. From a quick glance at the PDF documentation it appears to be a typical REST API, using HTTP on port 8090 on the SoundTouch device, with an SGML-style tag system to format messages. In so far as the community hasn’t already reverse-engineered this API it’s at least nice to have official documentation.

NPAPI And The Hot-Pluggable World Wide Web

January 9, 2026 by Maya Posch 11 Comments

In today’s Chromed-up world it can be hard to remember an era where browsers could be extended with not just extensions, but also with plugins. Although for those of us who use traditional Netscape-based browsers like Pale Moon the use of plugins has never gone away, for the rest of the WWW’s users their choice has been limited to increasingly more restrictive browser extensions, with Google’s Manifest V3 taking the cake.

Although most browsers stopped supporting plugins due to “security concerns”, this did nothing to address the need for executing code in the browser faster than the sedate snail’s pace possible with JavaScript, or the convenience of not having to port native code to JavaScript in the first place. This led to various approaches that ultimately have culminated in the WebAssembly (WASM) standard, which comes with its own set of issues and security criticisms.

Other than Netscape’s Plugin API (NPAPI) being great for making even 1990s browsers ready for 2026, there are also very practical reasons why WASM and JavaScript-based approaches simply cannot do certain basic things.

Continue reading “NPAPI And The Hot-Pluggable World Wide Web” →

Repairing Brittle Plastic Retro Computer Cases

January 8, 2026 by Maya Posch 17 Comments

Using UV resin as glue for new case clips. (Credit: More Fun Making It, YouTube)

As computers like the venerable breadbox Commodore 64 age, their plastic doesn’t just turn increasing shades of yellow and brown, the ABS plastic also tends to get brittle. This is a problem that seems to plague many plastic cases and enclosures, but fortunately there are some ways to halt or even reverse the heavy toll of time, with the [More Fun Making It] YouTube channel exploring a number of methods, including UV-curable resin, PETG 3D-printed clips and silicone molds.

Aside from large-scale damage, screw posts tend to snap off a lot, either during shipping or when merely trying to open the case. The same is true for the clips around the edge of the C64 case, which rarely survive that long. Gluing a case clip back on with epoxy or such somewhat works, but is messy and not that durable.

Instead UV resin is used, together with newly printed clips in translucent PETG. The remnants of the old clips are removed, followed by the application of the resin. The clips are actually a modified version of a VIC-20 case clip design by [Ken Mills]. With the UV resin as glue, curing is almost instant with a UV lamp unlike the tedious process with epoxy.

Continue reading “Repairing Brittle Plastic Retro Computer Cases” →

The Full-Sized 32-Wheeled, Articulated Bus Built For A 1976 Movie

January 8, 2026 by Maya Posch 68 Comments

Regardless of what your opinion is on cult-classic movies that got mixed-to-negative box office reviews when they were released, you have to admire the ones that went all out on practical effects and full-size constructions rather than CGI and scale models. Case in point the 1976 satirical comedy film The Big Bus that featured an absolutely massive articulated double-decker bus. With 32 wheels and multiple levels you’d think that a scale model would be used since most interior shots were done in the studio, but instead they built a real bus.

In this video by [Timeworn lengends] the genesis and details of the vehicle are covered. At the core of this road-worthy bus are two cabover International trucks, which were temporarily attached with a quick-release mechanism and required a second driver for the rear section who followed radio instructions for steering. In 1976 dollars, the entire bus prop cost between $250,000 and $500,000 USD to construct — making it one of the most expensive props ever made, especially considering the relatively low budget.

A fiberglass shell gave the bus its characteristic design, with the over the top ‘nuclear reactor’ propulsion befitting the comedy satire. Although the bowling alley and swimming pool were not really inside the bus, there was a functional bar installed along with the functional cockpit at the front.

Despite the movie flopping at the box office and critics being very mixed on its merits, it’s hard to deny that this bus prop is very unique and probably has a big part in why the movie has become a cult classic. As for the closest real-life equivalent, there is the articulated, double-decker Neoplan Jumbocruiser, which had its own troubled history.

Continue reading “The Full-Sized 32-Wheeled, Articulated Bus Built For A 1976 Movie” →