Why Fedora Decided To Give CC0 Licensed Code The Boot

The term “open source” can be tricky. For many people, it’s taken to mean that a particular piece of software is free and that they can do whatever they wish with it. But the reality is far more complex, and the actual rights you’re afforded as the user depend entirely on which license the developers chose to release their code under. Open source code can cost money, open source code can place limits on how you use it, and in some cases, open source code can even get you into trouble down the line.

Which is precisely what the Fedora Project is looking to avoid with their recent decision to reject all code licensed under the Creative Common’s “Public Domain Dedication” CC0 license. It will still be allowed for content such as artwork, and there may even be exceptions made for existing packages on a case-by-case basis, but CC0 will soon be stricken from the list of accepted code licenses for all new submissions.

Fedora turning their nose up at a software license wouldn’t normally be newsworthy. In fact, there’s a fairly long list of licenses that the project deems unacceptable for inclusion. The surprising part here is that CC0 was once an accepted license, and is just now being reclassified due to an evolving mindset within the larger free and open source (FOSS) community.

So what’s the problem with CC0 that’s convinced Fedora to distance themselves from it, and does this mean you shouldn’t be using the license for your own projects?

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Hackaday Podcast 179: Danger Chess, Corona Motors, An Omni-Walker, And A Fast Talking Telescope

Join Hackaday Editor-in-Chief Elliot Williams and Staff Writer Dan Maloney for their take on the hottest hacks in a hot, hot week. We found a bunch of unusual mechanisms this week, like an omnidirectional robot that’s not quite wheeled but not quite a walker either. Or, if you’d rather fly, there’s a UAV that’s basically a flying propeller. There’s danger afoot too, with news of a chess-playing robot with a nasty streak, a laser engraver that’ll probably blind you, and a high-voltage corona motor that actually does useful work. We’ll use our X-ray vision to take a deep dive into a 60-GHz phased array antenna, let a baby teach a machine what it means to be hungry, and build a couple of toy cameras just for funsies. Balloons as a UI? Maybe someday, thanks to ultrasonic levitation. And we’ll wrap things up by snooping in on the Webb telescope’s communications, as we find out how many people it takes to make wire harnesses. Spoiler alert: it’s a lot.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download here!

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Go Big Or Go Home: 0.6 Mm Nozzles Are The Future

Most desktop fused deposition modeling (FDM) 3D printers these days use a 0.4 mm nozzle. While many people have tried smaller nozzles to get finer detail and much larger nozzles to get faster printing speed, most people stick with the stock value as a good trade-off between the two. That’s the conventional wisdom, anyway. However, [Thomas Sanladerer] asserts that with modern slicers, the 0.4 mm nozzle isn’t the best choice and recommends you move up to 0.6 mm.

If you know [Thomas], you know he wouldn’t make a claim like that without doing his homework. He backs it up with testing, and you can see his thoughts on the subject and the test results in the video below. The entire thing hinges on the Ultimaker-developed Arachne perimeter generator that’s currently available in the alpha version of PrusaSlicer.

We’ve experimented with nozzles as small as 0.1 mm and, honestly, it still looks like an FDM 3D print and printing takes forever at that size. But these days, if we really care about the detail we are probably going to print with resin, anyway.

There are a few slicer settings to consider and you can see the whole setup in the video. The part where an SLA test part is printed with both nozzles is particularly telling. This is something that probably shouldn’t print well with an FDM at all. Both nozzles had problems but in different areas.

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This Week In Security: Symbiote, Smart Locks, And CosmicStrand

Symbiote is a particularly nasty Linux rootkit, and we have the interesting case of two separate analysis releasing this week. Up first is [CyberMasterV] taking apart a very early sample of the malware. The primary purpose of Symbiote seems to be capturing SSH logins, and this version does so by hooking the Pluggable Authentication Modules (PAM) system to capture users logging in to the machine it resides on. It also watches for SSH and SCP binaries, and sniffs the terminal used by those binaries, thereby capturing outgoing credentials.

All this data gets packaged up as DNS queries and shuffled off to the Command and Control server. “Easy”, I hear you say, “just block DNS traffic to everywhere except a trusted DNS provider.” It’s more clever than that. The data is in the form of valid DNS subdomains. In full, it’s a DNS request to PacketNumber.MachineID.Data.px32.nss.atendimento-estilo[.]com, all appropriately encoded to be valid. Every request will be for a unique host name, so every request gets forwarded to the C&C controller, which does double duty as the authoritative DNS resolver for that domain. You might get some mileage out of blocking (or at least logging) very long DNS queries.

Symbiote also replaces the typical files and devices you would look at to find a potential problem. For instance, /proc/net/tcp is where the kernel reports open TCP connections. On an infected machine, a copy of this file is maintained by the malware, conveniently leaving out the connections resulting from the infections. Symbiote has a hook in fopen, so whenever a process tries to read this location, the read is redirected to the cooked version, neatly hiding the rootkit. This stealth feature is apparently also used to hide other malware from the same attackers that may be on the same machine.
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PERSEUS-9, The Dual-6502 Portable Machine That Should Have Been

A question: does anyone who was around in the early days of the 8-bit computer revolution remember a dual-CPU 6502 portable machine like this one? Or just a dual-CPU machine? Or even just a reasonably portable computer? We don’t, but that begs a further question: if [Mitsuru Yamada] can build such a machine today with parts that were available in the era, why weren’t these a thing back then?

We’re not sure we have an answer to that question, but it just may be that nobody thought of it. Or, if they did, the idea of putting two expensive CPUs into a single machine was perhaps too exorbitant to take seriously. Regardless, the homemade mobile is another in a growing line of beautifully crafted machines in the PERSEUS line, all of which have a wonderfully similar look and feel.

For the PERSEUS-9, [Yamada-san] chose a weatherproof aluminum enclosure with just the right form-factor for a mobile computer, as well as a sturdy industrial look. Under the hood, there are two gorgeous wire-wrap boards, one of which is home to the 48-key keyboard and the 40×7 alphanumeric LED matrix display, while the other is a densely packed work of art holding the two 6502s and a host of other DIPs.

The machine is a combination of his PERSEUS-8 computer, his 6802 serial terminal, and the CI-2 floating point interpreter he built for the PERSEUS-8. A brief video of the assembly of this delightful machine is below. One of the many things about these builds that impress us is the precision with which the case is machined, apparently all by hand. How he managed to drill out all those holes for the keyboard without having one even slightly out of alignment without the aid of CNC is beyond us.

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Love Is A Burning Flame, And So Is This Underwater Burning Ring Of Fire

When Johnny Cash wrote “Ring of Fire”, he was talking about love. But when an unnamed follower of [TheBackyardScientist] took it literally and suggested making actual rings of fire — underwater —  they rose to the challenge as you can see in the video below the break.

Of course there are several ingredients to underwater fire rings. First you need water, and a pool clearly does the job in this video. Second, you need flammable rings of gas. [TheBackyardScientist] decided to build a machine to create the gas rings, and it’s quite interesting to see them go through several iterations before settling on a voice coil based poppet valve design. We must say that it works absolutely swimmingly.

Lastly there needs to be fire. And for fire, you need something flammable, and something shocking. Forty thousands volts light up a spark plug, even underwater. The fuel is provided by what appears to be compressed air and acetylene but we’re not 100% sure. We are sure that it goes bang! quite sufficiently, as demonstrated by its aptitude for blowing things up.

We appreciated the engineering that went into the project but also the rapid iterations of ideas, the overcoming of serious obstacles and the actual science that went into the project. Even if it is just randomly making literal burning rings of fire.

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New OS For Commodore 64 Adds Modern Features

The Commodore 64 was a revolutionary computer for its day and age. After four decades, though, it gets harder and harder to use these computers for anything more than educational or hobby electronics projects. [Gregory Nacu] is fiercly determined to challenge this idea, though, and has gone to great extremes to make this hardware still relevant in the modern age by writing a completely new operating system for the Commodore machines.

Known as C64OS, it squeezes everything it can out of the 8 bit processor and 64 kB of memory. The new OS includes switchable desktop workspaces, a windowing system, draggable icons, a Mac-style menu bar at the top, and drop-down menus for the icons (known as aliases in the demonstrations). The filesystem is largely revamped as well and enables a more modern directory system to be used. There are still some limitations like a screen resolution of 320×200 pixels and a fixed color palette which only allows for a handful of colors, but this OS might give Windows 3.1 a run for its money.

The project is still being actively developed but it has come a long way into a fairly usable state. It can be run on original hardware as well as long as you have a method of getting the image to the antique machine somehow. If not, the OS can likely run on any number of C64 emulators we’ve featured in the past.

Thanks to [Stephen] for the tip!

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