Many of us used “big iron” back in the day. Computers like the IBM S/360 or 3090 are hard to find, transport, and operate, so you don’t see many retrocomputer enthusiasts with an S/370 in their garages. We’ve known for a while that the Hercules emulators would let you run virtual copies of these old mainframes, but every time we’ve looked at setting any up, it winds up being more work than we wanted to spend. Enter [Ernie] of [ErnieTech’s Little Mainframes]. He’s started a channel to show you how to “build” your own mainframe — emulated, of course.
One problem with the mainframe environment is that there are a bunch of operating system-like things like MVS, VM/CMS, and TSO. There were even custom systems like MUSIC/SP, which he shows in the video below.
[Stephen Woodward] is familiar with digital potentiometers but is also familiar with their limitations. That spurred him to create the PWMPot which performs a similar function, but with better features than a traditional digital pot. Of course, he admits that this design has some limitations of its own, so — as usual — you have to make your design choices according to what’s important to you.
Perhaps the biggest limitation is that the PWMPot isn’t useful at even moderately high frequencies. The circuit works by driving two CMOS switches into an RC circuit. The switches’ inverted phase tends to cancel out any ripple in the signal.
There are many AI models out there that you can play with from companies like OpenAI, Google, and a host of others. But when you use them, you get the experience they want, and you run it on their computer. There are a variety of reasons you might not like this. You may not want your data or ideas sent through someone else’s computer. Maybe you want to tune and tweak in ways they aren’t going to let you.
There are many more or less open models, but setting up to run them can be quite a chore and — unless you are very patient — require a substantial-sized video card to use as a vector processor. There’s very little help for the last problem. You can farm out processing, but then you might as well use a hosted chatbot. But there are some very easy ways to load and run many AI models on Windows, Linux, or a Mac. One of the easiest we’ve found is Msty. The program is free for personal use and claims to be private, although if you are really paranoid, you’ll want to verify that yourself.
What is Msty?
Talkin’ about Hackaday!
Msty is a desktop application that lets you do several things. First, it can let you chat with an AI engine either locally or remotely. It knows about many popular options and can take your keys for paid services. For local options, it can download, install, and run the engines of your choice.
For services or engines that it doesn’t know about, you can do your own setup, which ranges from easy to moderately difficult, depending on what you are trying to do.
Of course, if you have a local model or even most remote ones, you can use Python or some basic interface (e.g., with ollama; there are plenty of examples). However, Msty lets you have a much richer experience. You can attach files, for example. You can export the results and look back at previous chats. If you don’t want them remembered, you can chat in “vapor” mode or delete them later.
Each chat lives in a folder, which can have helpful prompts to kick off the chat. So, a folder might say, “You are an 8th grade math teacher…” or whatever other instructions you want to load before engaging in chat.
[Nicholas Carlini] found some extra time on his hands over the holiday, so he decide to do something with “entirely no purpose.” The result: 84,688 regular expressions that can play chess using a 2-ply minmax strategy. No kidding. We think we can do some heavy-duty regular expressions, but this is a whole other level.
As you might expect, the code to play is extremely simple as it just runs the board through series of regular expressions that implement the game logic. Of course, that doesn’t count the thousands of strings containing the regular expressions.
We always enjoy videos from the [Mathologer], but we especially liked the recent video on the Helicone, a toy with a surprising connection to mathematics. The toy is cool all by itself, but the video shows how a sufficiently large heliocone models many “natural numbers” and acts, as [Mathologer] puts it, acts as “microscope to probe the nature of numbers.”
The chief number of interest is the so-called golden ratio. A virtual model of the toy allows easy experimentation and even some things that aren’t easily possible in the real world. The virtual helicone also allows you to make a crazy number of layers, which can show certain mathematical ideas that would be hard to do in a 3D print or a wooden toy.
Apparently, the helicone was [John Edmark’s] sculpture inspired by DNA spirals, so it is no surprise it closely models nature. You can 3D print a real one.
Of course, the constant π makes an appearance. Like fractals, you can dive into the math or just enjoy the pretty patterns. We won’t judge either way.
We’ve seen math sequences in clocks that remind us of [Piet Mondrian]. In fact, we’ve seen more than one of those.
We found it nostalgic to watch [ve3iku] fire up an old Loran-A receiver and, as you can see in the video below, he got it working. If you aren’t familiar with LORAN, it was a common radio navigation technique before GPS took over everything.
LORAN — an acronym for Long Range Navigation — was a US byproduct of World War II and was similar in many ways to Britain’s Gee system. However, LORAN operated at lower frequencies to improve its range. It was instrumental in helping convoys cross the Atlantic and also found use in the Pacific theater.
We like mechanical calculators like slide rules, but we have to admit that we had not heard of the Ott Derivimeter that [Chris Staecker] shows us in a recent video. As the name implies, the derivimeter finds the derivative of a function. To do that, you have to plot the function on a piece of paper that the meter can measure.
If you forgot calculus or skipped it altogether, the derivative is the rate of change. If you plot, say, your car’s speed vs time, the parts where you accelerate or decelerate will have a larger derivative (either positive or negative, in the decelerate case). If you hold a steady speed, the derivative will be zero.
