Why Super Mario 64 Wastes So Much Memory

The Nintendo 64 was an amazing video game console, and alongside consoles like the Sony PlayStation, helped herald in the era of 3D games. That said, it was new hardware, with new development tools, and thus creating those early N64 games was a daunting task. In an in-depth review of Super Mario 64’s code, [Kaze Emanuar] goes over the curious and wasteful memory usage, mostly due to unused memory map sections, unoptimized math look-up tables, and greedy asset loading.

The game as delivered in the Japanese and North-American markets also seems to have been a debug build, with unneeded code everywhere. That said, within the context of the three-year development cycle, it’s not bad at all — with twenty months spent by seven programmers on actual development for a system whose hardware and tooling were still being finalized, with few examples available of how to do aspects like level management, a virtual camera, etc. Over the years [Kaze] has probably spent more time combing over SM64‘s code than the original developers, as evidenced by his other videos.

As noted in the video, later N64 games like Legend of Zelda: Ocarina of Time are massively more optimized and streamlined, as lessons were learned and tooling improved. For the SM64 developers, however, they had a gargantuan 4 MB of fast RDRAM to work with, so optimization and memory management likely got kicked down to the bottom on the priority list. Considering the absolute smash hit that SM64 became, it seems that these priorities were indeed correct.

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Tefifon: Germany’s Tape-Shaped Record Format

A Tefifon cartridge installed for playback. (Credit: Our Own Devices, YouTube)
A Tefifon cartridge installed for playback. (Credit: Our Own Devices, YouTube)

Recently the [Our Own Devices] YouTube channel took a gander at the Tefifon audio format. This was an audio format that competed with shellac and vinyl records from the 1930s to the 1960s, when the company behind it went under. Some people may already know Tefifon as [Matt] from Techmoan has covered it multiple times, starting with a similar machine about ten years ago, all the way up to the Stereo Tefifon machine, which was the last gasp for the format.

There’s a lot to be said for the Tefifon concept, as it fixes many of the issues of shellac and vinyl records, including the limited run length and having the fragile grooves exposed to damage and dust. By having the grooves instead on a flexible band that got spooled inside a cartridge, they were protected, with up to four hours of music or eight hours of spoken content, i.e. audio books.

Although the plastic material used for Tefifon bands suffered from many of the same issues as the similar Dictabelt audio recording system, such as relatively rapid wear and degradation (stiffening) of the plastic, it was mostly the lack of interest from the audio labels that killed the format. With the big labels and thus big artists heavily invested in records, the Tefifon never really got any hits and saw little use outside of West Germany throughout the 1950s and 1960s before its last factories were shuttered.

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PVDF: The Specialized Filament For Chemical And Moisture Resistance

There’s a dizzying number of specialist 3D printing materials out there, some of which do try to offer an alternative to PLA, PA6, ABS, etc., while others are happy to stay in their own niche. Polyvinylidene fluoride (PVDF) is one of these materials, with the [My Tech Fun] YouTube channel recently getting sent a spool of PVDF for testing, which retails for a cool $188.

Some of the build plate carnage observed after printing with PVDF. (Credit: My Tech Fun, YouTube)
Some of the build plate carnage observed after printing with PVDF. (Credit: My Tech Fun, YouTube)

Reading the specifications and datasheet for the filament over at the manufacturer’s website it’s pretty clear what the selling points are for this material are. For the chemists in the audience the addition of fluoride is probably a dead giveaway, as fluoride bonds in a material tend to be very stable. Hence PVDF ((C2H2F2)n) sees use in applications where strong resistance to aggressive chemicals as well as hydrolysis are a requirement, not to mention no hygroscopic inclinations, somewhat like PTFE and kin.

In the video’s mechanical testing it was therefore unsurprising that other than abrasion resistance it’s overall worse and more brittle than PA6 (nylon). It was also found that printing this material with two different FDM printers with the required bed temperature of 110°C was somewhat rough, with some warping and a wrecked engineering build plate in the Bambu Lab printer due to what appears to be an interaction with the usual glue stick material. Once you get the print settings dialed in it’s not too complicated, but it’s definitely not a filament for casual use.

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JuiceBox Rescue: Freeing Tethered EV Chargers From Corporate Overlords

The JuiceBox charger in its natural environment. (Credit: Nathan Matias)
The JuiceBox charger in its natural environment. (Credit: Nathan Matias)

Having a charger installed at home for your electric car is very convenient, not only for the obvious home charging, but also for having scheduling and other features built-in. Sadly, like with so many devices today, these tend to be tethered to a remote service managed by the manufacturer. In the case of the JuiceBox charger that [Nathan Matias] and many of his neighbors bought into years ago, back then it and the associated JuiceNet service was still part of a quirky startup. After the startup got snapped up by a large company, things got so bad that [Nathan] and others saw themselves required to find a way to untether their EV chargers.

The drama began back in October of last year, when the North American branch of the parent company – Enel X Way – announced that it’d shutdown operations. After backlash, the online functionality was kept alive while a buyer was sought.  That’s when [Nathan] and other JuiceBox owners got an email informing them that the online service would be shutdown, severely crippling their EV chargers.

Ultimately both a software and hardware solution was developed, the former being the JuicePass Proxy project which keeps the original hardware and associated app working. The other solution is a complete brain transplant, created by the folk over at OpenEVSE, which enables interoperability with e.g. Home Assistant through standard protocols like MQTT.

Stories like these make one wonder how much of this online functionality is actually required, and how much of it just a way for manufacturers to get consumers to install a terminal in their homes for online subscription services.

Google Will Require Developer Verification Even For Sideloading

Do you like writing software for Android, perhaps even sideload the occasional APK onto your Android device? In that case some big changes are heading your way, with Google announcing that they will soon require developer verification for all applications installed on certified Android devices – meaning basically every mainstream device. Those of us who have distributed Android apps via the Google app store will have noticed this change already, with developer verification in the form of sending in a scan of your government ID now mandatory, along with providing your contact information.

What this latest change thus effectively seems to imply is that workarounds like sideloading or using alternative app stores, like F-Droid, will no longer suffice to escape these verification demands. According to the Google blog post, these changes will be trialed starting in October of 2025, with developer verification becoming ‘available’ to all developers in March of 2026, followed by Google-blessed Android devices in Brazil, Indonesia, Thailand and Singapore becoming the first to require this verification starting in September of 2026.

Google expects that this system will be rolled out globally starting in 2027, meaning that every Google-blessed Android device will maintain a whitelist of ‘verified developers’, not unlike the locked-down Apple mobile ecosystem. Although Google’s claim is that this is for ‘security’, it does not prevent the regular practice of scammers buying up existing – verified – developer accounts, nor does it harden Android against unscrupulous apps. More likely is that this will wipe out Android as an actual alternative to Apple’s mobile OS offerings, especially for the hobbyist and open source developer.

One of the photo-detector spheres of ARCA (Credit: KM3NeT)

Confirmation Of Record 220 PeV Cosmic Neutrino Hit On Earth

Neutrinos are exceedingly common in the Universe, with billions of them zipping around us throughout the day from a variety of sources. Due to their extremely low mass and no electric charge they barely ever interact with other particles, making these so-called ‘ghost particles’ very hard to detect. That said, when they do interact the result is rather spectacular as they impart significant kinetic energy. The resulting flash of energy is used by neutrino detectors, with most neutrinos generally pegging out at around 10 petaelectronvolt (PeV), except for a 2023 event.

This neutrino event which occurred on February 13th back in 2023 was detected by the KM3NeT/ARCA detector and has now been classified as an ultra-high energy neutrino event at 220 PeV, suggesting that it was likely a cosmogenic neutrinos. When we originally reported on this KM3-230213A event, the data was still being analyzed based on a detected muon from the neutrino interaction even, with the researchers also having to exclude the possibility of it being a sensor glitch.

By comparing the KM3-230213A event data with data from other events at other detectors, it was possible to deduce that the most likely explanation was one of these ultra-high energy neutrinos. Since these are relatively rare compared to neutrinos that originate within or near Earth’s solar system, it’ll likely take a while for more of these detection events. As the KM3NeT/ARCA detector grid is still being expanded, we may see many more of them in Earth’s oceans. After all, if a neutrino hits a particle but there’s no sensor around to detect it, we’d never know it happened.


Top image: One of the photo-detector spheres of ARCA (Credit: KM3NeT)

Very Efficient APFC Circuit In Faulty Industrial 960 Watt Power Supply

The best part about post-mortem teardowns of electronics is when you discover some unusual design features, whether or not these are related to the original fault. In the case of a recent [DiodeGoneWild] video involving the teardown of an industrial DIN-rail mounted 24 V, 960 Watt power supply, the source of the reported bang was easy enough to spot. During the subsequent teardown of this very nicely modular PSU the automatic power factor correction (APFC) board showed it to have an unusual design, which got captured in a schematic and is explained in the video.

Choosing such a APFC design seems to have been done in the name of efficiency, bypassing two of the internal diodes in the bridge rectifier with the external MOSFETs and ultrafast diodes. In short, it prevents some of the typical diode voltage drops by removing diodes in the path of the current.

Although not a new design, as succinctly pointed out in the comments by [marcogeri], it’s explained how even cutting out one diode worth of voltage drop in a PSU like this can save 10 Watt of losses. Since DIN rail PSUs rarely feature fans for active cooling, this kind of APFC design is highly relevant and helps to prevent passively cooled PSUs from spiraling into even more of a thermal nightmare.

As for the cause behind the sooty skid marks on one of the PCBs, that will be covered in the next video.

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