A Magnetohydrodynamic Drive In The Kitchen Sink

August 7, 2023 by 58 Comments

The magnetohydrodynamic (MHD) drive certainly sounds like something out of science fiction — using an array of magnets and electrodes, this high-tech propulsion technology promises to silently propel a craft through the water without any moving parts. As long as you can provide it with a constant supply of electricity, anyway.

Of course, as is often the case, the devil is in the details. Even with the obvious scientific and military applications of such a propulsion unit, scaling MHD technology up has proven difficult. But as [Jay Bowles] of Plasma Channel shows in his latest video, that doesn’t mean you can’t experiment with the concept at home. Even better, getting verifiable results is much easier than you’d think.

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Jenny’s Daily Drivers: FreeBSD 13.2

August 1, 2023 by 28 Comments

Last month I started a series in which I try out different operating systems with the aim of using them for my everyday work, and my pick was Slackware 15, the latest version of the first Linux distro I tried back in the mid 1990s. I’ll be back with more Linux-based operating systems in due course, but the whole point of this series is to roam as far and wide as possible and try every reasonable OS I can. Thus today I’m making the obvious first sideways step and trying a BSD-based operating system. These are uncharted waters for me and there was a substantial choice to be made as to which one, so after reading around the subject I settled on FreeBSD as it seemed the most accessible.

First, A Bit Of Context

A PC with the FreeBSD boot screen
Success! My first sight of a working FreeBSD installation.

Most readers will be aware that the BSD operating systems trace their heritage in a direct line back to the original AT&T UNIX, while GNU/Linux is a pretty good UNIX clone originating with Linus Torvalds in the early 1990s and Richard Stallman’s GNU project from the 1980s onwards. This means that for Linux users there’s a difference in language to get used to.

Where Linux is a kernel around which distributions are built with different implementations of the userland components, the various BSD operating systems are different operating systems in their own right. Thus we talk about for example Slackware and Debian as different Linux distributions, but by contrast NetBSD and FreeBSD are different operating systems even if they have a shared history. There are BSD distributions such as GhostBSD which use FreeBSD as its core, but it’s a far less common word in this context. So I snagged the FreeBSD 13.2 USB stick file from the torrent, and wrote it to a USB Flash drive. Out with the Hackaday test PC, and on with the show. Continue reading “Jenny’s Daily Drivers: FreeBSD 13.2” →

DIY All-Flash NAS Vs. Commercial Hardware

July 20, 2023 by 37 Comments

[Jeff Geerling] has tried building his own network-attached storage before, but found that the Raspberry Pi just wasn’t able to keep pace with his demands. He’s back with a new all-flash NAS build, and put his new design to the test against proper store-bought gear.

His build is based around the ROCK 5 Model B, which is able to truck data around far faster than most other single-board computers. Internally, it can top 1 GB/sec without too much hassle. He decided to build a NAS rig using the board, putting it up against the turn-key ASUSTOR AS-T10G3.

Using OpenMediaVault to run the ROCK 5 as a NAS, [Jeff] was able to get decent performance out of the setup. With a 3-drive RAID 5 configuration, he recorded write and read speeds of 100 MB/sec and 200 MB/sec respectively, over a 2.5 Gbps network connection. There were also some spikes and curious performance wobbles. While speed was better than [Jeff]’s previous Raspberry Pi experiments, it wasn’t capable of double or triple the performance like he’d hoped. In comparison, the ASUSTOR solution was capable of much greater speeds. It topped out at 600 MB/sec write speeds, and 1.2 GB/sec on reads.

If you’re looking to build a high-performance DIY NAS, the ROCK 5 may be a better solution than most Raspberry Pi boards. However, if you want speed over all else, existing commercial NAS solutions really have the edge. Video after the break.

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Linux Device Drivers In Only A Few Years

July 11, 2023 by 10 Comments

[Johannes 4GNU_Linux] has been filming a video series on how to write Linux device drivers for a couple of years now, but luckily, you won’t need that long to watch them or to create your own driver. He’s added some recent videos to the series, like the one below, but might want to rewind a few years and start at the beginning.

If you build your own hardware for Linux, you’ll probably eventually want to write a driver which runs as a privileged program. While there are many things you can do in user space, for the ultimate control and performance, you can’t beat a driver.

One problem, though, is that drivers can really crash your system in a big way. In the old days, it was common to have a dedicated system for driver development. Today, for many drivers, you can get away with running a virtual machine that you can crash and reload without much trouble.

The videos cover diverse topics like interrupts, completions, polling, and threads. He even uses a Raspberry Pi, which will be very useful for many embedded projects. Of course, the trend these days is to have one driver — like the USB driver — and have it provide user-space access so that everyone doesn’t have to write their own drivers. But, as usual, that only goes so far.

We aren’t sure how many more videos there will be, but if you make it through the first 31, maybe more will be waiting for you. It has been a while since we looked at SPI drivers in Linux. As an example of why you might want to roll your own, consider a custom FPGA driver.

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Jenny’s Daily Drivers: Slackware 15

July 10, 2023 by 50 Comments

As a recent emigre from the Ubuntu Linux distribution to Manjaro, I’ve had the chance to survey the field as I chose a new distro, and I realised that there’s a whole world of operating systems out there that we all know about, but which few of us really know. Hence this is the start of what I hope will be a long-running series, in which I try different operating systems in my everyday life as a Hackaday writer, to find out about them and then to see whether they can deliver on the promise of giving me a stable platform on which to earn a living.

For that they need an internet connection and a web browser up-to-date enough to author Hackaday stories, as well as a decent graphics package. In addition to using the OS every day though, I’ll also be taking a look at what makes it different from all the others, what its direction and history is, and how user-friendly it is as an experience. Historical systems such as CP/M are probably out of the question as are extremely esoteric ones such as the famous TempleOS, but this still leaves plenty of choice for an operating system tourist. Join me then, as I try all the operating systems.

A Distro From The 1990s, Today

A desktop mini tower PC with monitor showing the Slackware boot screen
The Hackaday test PC gets its first outing.

When deciding where to start on this road, there was an obvious choice. Slackware was the first Linux-based distribution I tried back in 1995, I’m not sure which version it was , but it came to me via a magazine coverdisk. It was by no means the first OS that captured my attention as I’d been an Amiga user for quite a few years at that point, but at the moment I can’t start with AmigaOS as I don’t have nay up-to-date Amiga-compatible hardware.

July 2023 also marks the 30th anniversary for the distro making it the oldest one still in active development, so this seems the perfect month to start this series with the descendant of my first Linux distro. Slackware 15 comes as a 3.8 GB ISO file download for 64-bit computers, and my target for the distro was an old desktop PC with an AMD processor and a big-enough spinning rust hard disk which had been a high-end gaming system a little over ten years ago. Not the powerhouse it once was, but it cost me nothing and it’s adequate for my needs. Installed on a USB Flash drive the Slackware installer booted, and I was ready to go. Continue reading “Jenny’s Daily Drivers: Slackware 15” →

Updated OSHW Flash Drive Keeps Data Safe, Fingers Dry

June 14, 2023 by 27 Comments

For almost a year now, we’ve been following the progress [Walker] has been making with Ovrdrive — a completely open source USB flash drive that features the ability to destroy itself should it fall into the wrong hands. It’s an interesting enough project on those merits alone, but what really made this idea stand out was that the user was expected to lick their fingers before handling the drive as a form of covert authentication.

Well, we’ve got some good news and some bad news. The good news is that [Walker] is just about ready to release the Ovrdrive officially on Crowd Supply. But it’s with a heavy heart that we must report that the device’s cutting edge spit-detection capabilities have been removed. Now if you want to preserve the drive’s files, you need to rapidly insert and remove the drive several times rather than just plugging it in.

In all seriousness, this new approach makes a lot more sense. As entertaining as it might have been, the whole idea of a device that could detect moisture on the user’s fingers was fraught with problems. It was a bit more of a meme than a real solution, and if we’re being honest, kind of disgusting. This new approach sounds far more reliable, especially when combined with the new “Lite” self-destruct mode.

While the original capability of literally frying the flash chip by way of several capacitors and a voltage doubler is still here, there’s also a non-destructive approach that’s enabled by default. Unless you open up the drive and desolder the jumper pad on the PCB, the onboard ATtiny24A will simply use the enable pin on the flash chip to make it appear empty. This means that you’ve got to really want to cook your flash chip on the first hint of funny business.

Ultimately, whether it’s self-destructing or not, we just really like the idea of a hacker-developed open source hardware USB flash drive. Admittedly it would be a lot cheaper and more practical to just buy one like a normal person, but we strongly believe that if there’s a way for the community to build a OSHW version of something, they should at least give it a shot.

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Crafting Ribbon Cables For Retro Hardware

June 10, 2023 by 23 Comments

Building a modern computer is something plenty of us have done, and with various tools available to ensure that essentially the only thing required of the end user is to select parts and have them delivered via one’s favorite (or least expensive) online retailer. Not so with retro hardware, though. While some parts can be found used on reselling sites like eBay, often the only other option is to rebuild parts from scratch. This is sometimes the best option too, as things like ribbon cables age poorly and invisible problems with them can cause knock-on effects that feel like wild goose chases when troubleshooting. Here’s how to build your own ribbon cables for your retro machines.

[Mike] is leading us on this build because he’s been working on an old tower desktop he’s calling Rosetta which he wants to be able to use to host five different floppy disk types and convert files from one type to another. Of course the old hardware and software being used won’t support five floppy disk drives at the same time so he has a few switches involved as well. To get everything buttoned up neatly in the case he’s building his own ribbon cables to save space, especially since with his custom cables he won’t have the extraneous extra connectors that these cables are famous for.

Even though, as [Mike] notes, you can’t really buy these cables directly anymore thanks to the technology’s obsolescence, you can still find the tools and parts you’d need to create them from scratch including the ribbon, connectors, and crimping tools. Even the strain relief for these wide, fragile connectors is available and possible to build into these projects. It ends up cleaning up the build quite nicely, and he won’t be chasing down any gremlins caused by decades-old degraded multi-conductor cables. And, even though [Mike] demonstrated the floppy disk drive cables in this build, ribbon cable can be used for all kinds of things including IDE drive connectors and even GPIO cables for modern electronics projects.

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