MS-DOS Meets The Fediverse

August 9, 2023 by Bryan Cockfield 30 Comments

By now, most Windows users are set up with decently functional machines running Windows 10 or 11. Of course there are a few legacy machines still lagging behind on Windows 7 or 8 and plenty of computers in industrial settings running ancient proprietary software on Windows XP. But only the most hardcore of IBM PC users are still running DOS, and if you have eschewed things like Unix for this command-line operating system this long you might want to try using it to get online in the Fediverse with Mastodon.

The first step is getting DOS 6.22, the most recent version released in 1994, set up with all the drivers and software needed to access the Internet. At the time of its release there were many networking options so the operating system didn’t include these tools by default. [Stephen] first sets up an emulated NE2000-compatible networking card and then installs the entire TCP/IP stack and then gets his virtual machine set up with an IP address.

With a working Internet connection set up, the next step on the path of exploring federated social media is to install DOStodon (although we might have favored the name “MastoDOS”) which is a Mastodon client specifically built for MS-DOS by [SuperIlu]. There are pre-compiled packages available on its GitHub page for easy installation in DOS but the source code is available there as well. And, if this is your first time hearing about the Fediverse, it is mostly an alternative to centralized social media like Facebook and Reddit but the decentralization isn’t without its downsides.

Super Mario In Sed, Sort Of

August 9, 2023 by Dave Rowntree 7 Comments

We definitely needed to reach for a sed reference guide for this one, but looking at the animated GIF of the script running, it is recognizably Super Mario Bros. albeit with minimal gameplay beyond jumping obstacles and avoiding or destroying koopas et al. Creator [Ivan Chebykin] is for certain a master of the dark arts.

Digging in a bit deeper, it’s not strictly speaking 100% sed. A wrapper shell script is required to interface to the shell and grab the keyboard input to pass along. This is simply because sed is a stream processor, and as such it requires text to be fed into it, and it produces a text output. It has no way of reading the terminal input directly, hence the wrapper script. However, all the game logic and ‘graphics’ rendering is pure sed, so that’s perfectly reasonable.

Such programming demos are a great way to hone the finer points of various tools we use every day, whilst not being serious enough to matter if we fail. Pushing the boundaries of what can be done with these basic nuts and bolts we take for granted, is for us the very essence of software hacking, and bravo we say.

Reckon you could top this? Show us! In the meantime, here’s a guide to hacking the recently released Game and Watch, and then doing the decent thing and running DOOM on it. Finally, sed is notoriously tricky to work with, so to help here’s a graphical debugger to make things a little clearer.

The Orb Web Desktop

August 8, 2023 by Dave Rowntree 28 Comments

[Hugo Leisink] is a programmer who contributes to Open Source projects. In their spare time, they have been developing a web-browser-based operating system called Orb. It is available for the princely sum of zero cheeseburgers and doesn’t need a high-spec machine to run smoothly. The project is built using PHP and Javascript, which allows it to run efficiently on most desktop devices. There are a number of apps included, which are again written in a combination of PHP and js, together with a few written using webasm.

A few notable examples include a C64 emulator, minesweeper, and even a js port of Wolfenstein 3D so this isn’t just a toy, but actually useful. Ok, for real use cases, there are also the usual file browsers, and document readers as well as a writing application based on CKeditor. There is a kind of Windows 3.1 look and feel simplicity to the experience which is refreshing in the modern era of complex applications with their learning curves. Orb could be very useful in an educational setting, or just for jotting your own notes as you travel. Who knows, because the possibilities are endless if you’re willing to get your hands dirty with a bit of coding.

We’ve seen a few web desktops before, here’s a collection of them we saw last year. If you want to go in the other direction and turn a webpage into a desktop app, then look no further than Gluon.

Browser-Based Robot Dog Simulator In ~800 Lines Of Code

August 5, 2023 by Donald Papp 9 Comments

[Sergii] has been learning about robot simulation and wrote up a basic simulator for a robodog platform: the Unitree A1. It only took about 800 lines of code to do so, which probably makes it a good place to start if one is headed in a similar direction.

Right now, [Sergii]’s simulator is an interactive physics model than runs in the browser. Software-wise, once the model of the robot exists the Rapier JavaScript physics engine takes care of the physics simulation. The robot’s physical layout comes from the manufacturer’s repository, so it doesn’t need to be created from scratch.

To make the tool useful, the application has two models of the robot, side by side. The one on the left is the control model, and has interactive sliders for limb positions. All movements on the control model are transmitted to the model on the right, which is the simulation model, setting the pose. The simulation model is the one that actually models the physics and gravity of all the desired motions and positions. [Sergii]’s next step is to use the simulator to design and implement a simple walking gait controller, and we look forward to how that turns out.

If Unitree sounds familiar to you, it might be because we recently covered how an unofficial SDK was able to open up some otherwise-unavailable features on the robodogs, so check that out if you want to get a little more out of what you paid for.

Kalman Filters Without The Math

August 2, 2023 by Al Williams 25 Comments

If you program using values that represent anything in the real world, you have probably at least heard of the Kalman filter. The filter allows you to take multiple value estimates and process them into a better estimate. For example, if you have a robot that has an idea of where it is via GPS, dead reckoning, and an optical system, Kalman filter can help you better estimate your true position even though all of those sources have some error or noise. As you might expect, a lot of math is involved, but [Pravesh] has an excellent intuitive treatment based around code that even has a collaborative Jupyter notebook for you to follow along.

We have always had an easier time following code than math, so we applaud these kinds of posts. Even if you want to dig into the math, having basic intuition about what the math means first makes it so much more approachable.

Continue reading “Kalman Filters Without The Math” →

Jenny’s Daily Drivers: FreeBSD 13.2

August 1, 2023 by Jenny List 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” →

An Open-Source, Free Circuit Simulator

July 30, 2023 by Bryan Cockfield 60 Comments

The original circuit simulation software, called the Simulation Program with Integrated Circuit Emphasis, or SPICE as it is more commonly known, was originally developed at the University of Califorina Berkeley in the 1970s with an open-source license. That’s the reason for the vast versions of SPICE available now decades after the original was released, not all of which are as open or free as we might like. Qucs is a GPL circuit simulator. And if you want the GUI option, you might want to try out QucsStudio, which uses Qucs under the hood, and is free to use, but binary-only.

(Editor’s note: the author was confused between the GPL open-source Qucs and the closed-source, binary-only QucsStudio. We’ve cleaned that up.)

QucsStudio supports a wide range of circuit components and models much in the same fashion as other more popular SPICE programs, including semiconductor devices, passive components, and digital logic gates. Qucs also utilizes SPICE-based simulation, which can model various types of circuit behavior, such as DC, AC, transient, and small-signal analysis.

Unfortunately there are only Windows versions available, and although some might have some success running it under WINE. There are plenty of other options for those of us running non-Windows operating systems though. Here’s a review of 30 of them.

Thanks to [Electroagenda] for the tip!