Mars Pathfinder: What Really Happened?

October 11, 2026 by Al Williams No comments

You’ve probably heard of Mars Pathfinder, the NASA lander and its Sojourner rover that took up residence on Mars in 1997. At first, all was well, but after a few days, the lander suffered a series of total system resets. A watchdog timer detected a problem and forced reboots. [Vivek Bhageria’s] recent post looks into what happened and the eventual solution.

The root cause was priority inversion. This happens when a lower-priority task holds a resource needed by a higher-priority task and prevents the higher-priority task from executing. In this case, the operating system was VxWorks, but this can happen on any kind of priority scheduling system.

The simplified version is that there were two tasks that each used the same mutex to avoid stepping on each other. The highest priority was a data distribution task. The lowest priority task dealt with meteorology data processing. There was also a medium-priority task that handled bus maintenance.

The failure would occur when the low-priority task had the mutex and lost its time slot before releasing it. The high-priority task would then find it couldn’t take the mutex. However, the low-priority task didn’t get control again because of the medium-priority tasks waiting to run.

In effect, the high-priority task was now waiting on something that couldn’t become available until the lowest-priority task was able to run. That’s priority inversion.

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Slim Type For Small Screens, With PixelFonts

October 10, 2026 by Donald Papp No comments

Small displays are affordable and easy to use, but their size can present a challenge. To help address this, [mcer12] created PixelFonts, a family of condensed fonts designed specifically for low-resolution displays, making sure every line holds as much text as it can fit.

PixelFonts works alongside either the AdafruitGFX or U8g2 libraries; one writes to the display using the common syntax of the chosen library, and the font itself comes from PixelFonts. Text can be displayed in regular and 3D shadowed versions, as well as in a wide variety of heights and weights. There’s support for accented letters, albeit only in lowercase due to space constraints. Want to make some changes? Every font comes with a BDF file to make alterations as widely accessible as possible.

Making the most of every pixel is important with small displays, but there’s more than one way to do so. For example, when it comes to color LCDs, subpixel rendering can improve legibility of small fonts; another way to get the most out of limited display sizes.

Unique Archeological Discovery Sheds Light On Neanderthal Wooden Tool Usage

October 10, 2026 by Maya Posch 1 Comment

The Abric Romaní site in Spain is rather unique in archeology for one simple reason: the caves in its limestone-rich cliff have seen humanoid occupation for thousands of years. A thick layer of calcium carbonate-based travertine deposit has, over time, covered and largely preserved tools and other implements, including those made of wood. Over many decades of archeological exploration, 597 wooden imprints have been uncovered, with a recent research article by [Palmira Saladié] et al. detailing these findings.

Wood is one of those archaeological artefacts that are very elusive due to their fragility, even though we know that wood has been used pretty much everywhere from the first day that a humanoid critter discovered that branches make great clubs and spears, and can also easily be shaped to make them even more useful.

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Poking At The Radxa Dragon Q8B Raspberry Pi 5 Killer

October 10, 2026 by Maya Posch 12 Comments

Although the asking price of $209 plus shipping seems high for the Radxa Dragon Q8B, featuring the Qualcomm SC8280XP and 8 GB of LPDDR4X, this is 2026, and amid the RAMpocalypse, even the 8 GB LPDDR4X-equipped Raspberry Pi 5 now costs $175. This, to [Jeff Geerling], makes it fair to directly compare the two to see whether you may want to consider this board for more intense computing purposes.

There’s also a written summary of the results and details in a GitHub issue, though the direct comparison with the Raspberry Pi 5 is in the video.

Although this Qualcomm SoC isn’t new, its primary use is for Windows laptops, which gives somewhat of a hint as to what its performance may be like, tempered by the fact that it was announced in 2021.

The Dragon QXB offers about 2x everything over the RPi5, plus Windows and UEFI support. For Linux, it appears that you still need customized images, which seems perplexing in light of the UEFI aspect. You also have to pick between different Linux images from Radxa and use their Rsetup update tool, making it a less than newbie-friendly offering.

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Valve Releases Hardware And CAD Reference For New VR Headset

October 10, 2026 by Donald Papp 5 Comments

Valve recently began shipping its long-awaited VR headset, the Steam Frame. Now, there is a hardware reference repository that includes everything a budding modder might need, and then some.

No need to 3D scan or break out the calipers if one wants to design their own add-ons.

Want to design and 3D print some add-ons, or a carrying case, or some other doodad? There’s no need to break out the calipers or 3D scan the hardware. The repository contains STEP format models of the VR core module, head strap, and controllers, so it’s as easy as possible to design things that’ll fit. The location of the IR tracking LEDs embedded in the controllers is also documented, so one can ensure their design doesn’t occlude them.

That’s not all. The Frame has a user-accessible hardware expansion port at its front. This port exposes two interfaces: high-speed MIPI camera and PCI Express. This expansion port is documented in the repository, and even has a simple reference design built in both KiCad and Altium.

We’re glad to see Valve maintain their hacker-friendly hardware design with the Steam Frame. Demand for The Frame outstrips supply so far, so if you’re on the waitlist, you might want to browse the repository and get an early start on whatever customizations you have in mind while you wait for your confirmation. And when you get something working, drop us a note on the tips line!

A man's arm is shown against a mountainous backdrop. The man is wearing a black watch with an orange segment on one side.

Restoring An Altimeter Watch To Former Heights

October 10, 2026 by Aaron Beckendorf No comments

Finding inexpensive broken hardware for sale, buying it, and restoring it to working condition is a long-standing tradition for hackers on a limited budge. But there are some devices that are so difficult to repair that it’s usually not worth the trouble. [Vintage560] is braver than most, though, and restored an internally-damaged Casio AW-330-AT altimeter watch.

The exterior of the watch was in good condition, other than missing a readily-replaced strap, but the battery had leaked into the interior, and the watch didn’t respond in any way to new batteries. Cleaning out the guts with isopropyl alcohol, repositioning a plastic insulator, and bending some contacts back into shape at least got some segments of the LCD display to activate, while over two days of turning the crown smoothed out resistance in the analog train.

Actually getting the LCD to work properly required disassembling the watch, taking particular care with the altitude sensor. It wasn’t clear what was wrong with the LCD — the controller seemed to be working properly, and several rounds of cleaning and adjusting the ZEBRA connector didn’t make any difference.

Eventually, [Vintage560] simply purchased a new screen. On close inspection, it looked as though chemicals from the leaking battery might have dissolved some of the transparent indium tin oxide contacts on the old display. With the watch now working [Vintage560] tested it on a trip to the Alps, and with a few periodic calibrations, it remained quite accurate.

Usually when we see Casio watch hacks, the watch in question is the F91W, whether it’s being used for contactless payments, being retrofitted as a smartwatch, or going 5,000 meters underwater.

The Weirdest Video Games Were Hacks

October 10, 2026 by Elliot Williams 16 Comments

We were looking into the marvelous recent project by [Throaty Mumbo] to recreate and reimagine the forgotten world of VHS-tape-based video games. Wait, what? Yes, back in the day, when computer graphics were more primitive, there were attempts to mix the gameplay of video games with the graphics from a video cassette. Take the Action Max system. It worked with a light-gun that pointed at the screen while the video played, and you tried to shoot at things as they flew by. Think Duck Hunt, but in glorious VHS video quality with cheesy acting, and the same gameplay loop every time, because it’s on the tape.

The unreleased Control-Vision VHS gaming system, co-developed with none other than Steve Wozniak, took the idea a little further and ran simultaneous sub-videos, and your actions would choose which of the sub-tracks would play at any given time. This let them do things like switch between videos depending on whether you caught the bad guys or missed them entirely, for instance.

These games came in the late 1980s, though, and they were all derivatives of the seminal Dragon’s Lair, which is probably the least fun video game I’ve ever had the chance to play, but among the most entertaining in a weird way. Instead of a linear VHS tape, Dragon’s Lair, and the later but equally unplayable Space Ace, were based on the then-new video disc technology that could swap between entirely different tracks almost seamlessly.

“Almost” is the key word here, though. Although the animations were absolutely marvelously cartoony, and looked stunning in an arcade up against video games of the time, there was a significant fraction of a second of delay between commanding an action with the joystick and the machine swapping up to the correct track. There were a couple of sections where back-to-back actions were necessary, and the challenge was to work around the game’s exact track-swapping-glitch time. As good as they looked, the gameplay was no fun.

But the game was influential, as evidenced by its VHS-based clones. If you’d like to give it a try, you’ll not be surprised to hear that there’s an emulator for Dragon’s Lair and its spin-off games.

What do all of these have to do with each other? We love how these games took a current technology – in this case video discs or video tapes – and tried to make it do something else: These games were all hacks. If you look at them in that light, maybe you can look past the horrible acting in Night Trap or the frustrating glitches in Dragon’s Lair. (Or maybe not. Give me Robotron: 2084 any day.)