Why 56k Modems Relied On Digital Phone Lines You Didn’t Know We Had

March 6, 2025 by 51 Comments

If you came of age in the 1990s, you’ll remember the unmistakable auditory handshake of an analog modem negotiating its connection via the plain old telephone system. That cacophony of screeches and hisses was the result of careful engineering. They allowed digital data to travel down phone lines that were only ever built to carry audio—and pretty crummy audio, at that.

Speeds crept up over the years, eventually reaching 33.6 kbps—thought to be the practical limit for audio modems running over the telephone network. Yet, hindsight tells us that 56k modems eventually became the norm! It was all thanks to some lateral thinking which made the most of the what the 1990s phone network had to offer.

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Hack On Self: Quest System Basics

February 7, 2025 by 7 Comments

Whenever I play an RPG, whether it’s Fallout or Cyberpunk 2077, I complete every single quest available to me. The quests grab my attention in an unprecedented way – doesn’t hurt that there’s rewards and progression markers attached. Of course, these systems are meticulously designed to grab attention, making sure you can enjoy the entirety of the game’s content.

Does quest progression in an RPG tangibly impact my life? No. Do they have control over my attention? Yes, for sure. My day-to-day existence is the opposite – my real-life decisions impact me significantly, and yet, keeping attention on them is a struggle. Puzzling, disturbing – and curious. I feel like I’ll never forgive myself if I ignore this problem any longer.

So, I wrote a simple quest system prototype. As usual, it worked, it failed, and it taught me things. Here’s how I did it.

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The Bendix G-15 Runs 75,000 Lines Of Code

December 21, 2024 by 16 Comments

There’s a Blue Bendix in Texas, and thanks to [Usagi Electric] it’s the oldest operating computer in North America.  The Bendix G-15, a vacuum tube computer originally released in 1956, is now booting, and running code from paper tape. [David, aka Usagi] received the G-15 about a year ago from The System Source museum. The goal was to get the computer running so museum patrons could interact with a real tube computer. We’ve been following along since the project began.

[Usagi’s] latest G-15 video covers the last few problems on the road to running code. The biggest hurdle was the fact that the system wasn’t responding properly to the GO button on the typewriter. [Usagi] was able to isolate the issue down to a flip flop and then to a particular signal on an AND gate — the RC signal. The gate appeared to be bad, but swapping the entire circuit card multiple times had no effect. Something else had to be going on.

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New Release Of Vision Basic: Hot New Features!

September 23, 2024 by 7 Comments

As the Commodore 64 ages, it seems to be taking on a second life. Case in point: Vision BASIC is a customized, special version of the BASIC programming language with a ton of features to enable Commodore 64 programs to be written more easily and with all sorts of optimizations. We’ve tested out both the original 1.0 version of Vision BASIC, and now with version 1.1 being released there are a whole host of tweaks and updates to make the experience even better!

One of the only limitation of Vision BASIC is the requirement for expanded RAM. It will not run on an unexpanded C64 — but the compiled programs will, so you can easily distribute software made using Vision on any C64. A feature introduced in version 1.1 is support for GeoRAM, a different RAM expansion cartridge, and modern versions of GeoRAM like the NeoRAM which has battery-backed RAM. This allows almost instantaneous booting into the Vision BASIC development environment.

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Linux Fu: Failing Pipelines

July 25, 2024 by 16 Comments

Bash is great for automating little tasks, but sometimes a little script you think will take a minute to write turns into a half hour or more. This is the story of one of those half-hour scripts.

I have too many 3D printers. In particular, I have three that are almost — but not exactly — the same, so each one has a slightly different build process when I want to update their firmware. In all fairness, one of those printers is heading out the door soon, but I’ll probably still wind up building firmware images for it.

My initial process was painful. I have a special directory with the four files needed to configure Marlin for each machine. I copy all four files and ask PlatformIO to perform the build. Usually, it succeeds and gives me a file that looks like firmware-yyyyddmmhhmm.bin or something like that.

The problem is that the build process doesn’t know which of the three machines is the target: Sulu, Checkov, or Fraiser. (Long story.) So, I manually look at the file name, copy it, and rename it. Of course, this is an error-prone process, and I’m basically lazy, so I decided to write a script to do it. I figured it would take just a minute to bundle up all the steps. I was wrong.

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Is Your Mental Model Of Bash Pipelines Wrong?

March 28, 2024 by 11 Comments

[Michael Lynch] encountered a strange situation. Why was compiling then running his program nearly 10x faster than just running the program by itself? [Michael] ran into this issue while benchmarking a programming project, pared it down to its essentials for repeatability and analysis, and discovered it highlighted an incorrect mental model of how bash pipelines worked.

Here’s the situation. The first thing [Michael]’s pared-down program does is start a timer. Then it simply reads and counts some bytes from stdin, then prints out how long it took for that to happen. When running the test program in the following way, it takes about 13 microseconds.

$ echo '00010203040506070809' | xxd -r -p | zig build run -Doptimize=ReleaseFast
bytes: 10
execution time: 13.549µs

When running the (already-compiled) program directly, execution time swells to 162 microseconds.

$ echo '00010203040506070809' | xxd -r -p | ./zig-out/bin/count-bytes
bytes: 10
execution time: 162.195µs

Again, the only difference between zig build run and ./zig-out/bin/count-bytes is that the first compiles the code, then immediately runs it. The second simply runs the compiled program. Continue reading “Is Your Mental Model Of Bash Pipelines Wrong?” →

User Beware: The Fine Line Between Content And Code

March 25, 2024 by 29 Comments

Everyone loves themes. Doesn’t matter if it’s a text editor or a smart display in the kitchen, we want to be able to easily customize its look and feel to our liking. When setting up a new device or piece of software, playing around with the available themes may be one of the first things you do without giving it much thought. After all, it’s not like picking the wrong one is going to do something crazy like silently delete all the files on your computer, right?

Unfortunately, that’s exactly what happened a few days ago to [JeansenVaars] while trying out a Plasma Global Theme from the KDE Store. According to their Reddit post, shortly after installing the “Gray Layout” theme for the popular Linux graphical environment, the system started behaving oddly and then prompted for a root password. Realizing something didn’t seem right they declined, but at that point, it was already too late for all of the personal files in their home directory.

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