Intuition About Maxwell’s Equations

November 13, 2024 by 13 Comments

You don’t have to know how a car engine works to drive a car — but you can bet all the drivers in the Indy 500 have a better than average understanding of what’s going on under the hood. All of our understanding of electronics hinges on Maxwell’s equations, but not many people know them. Even fewer have an intuitive feel for the equations, and [Ali] wants to help you with that. Of course, Maxwell’s gets into some hairy math, but [Ali] covers each law in a very pragmatic way, as you can see in the video below.

While the video explains the math simply, you’ll get more out of it if you understand vectors and derivatives. But even if you don’t, the explanations provide a lot of practical understanding

Understanding the divergence and curl operators is one key to Maxwell’s equations. While this video does give a quick explanation, [3Blue1Brown] has a very detailed video on just that topic. It also touches on Maxwell’s equations if you want some reinforcement and pretty graphics.

Maxwell’s equations can be very artistic. This is one of those topics where math, science, art, and history all blend together.

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Remember The Tri-Format Floppy Disk?

November 12, 2024 by 18 Comments

These days, the vast majority of portable media users are storing their files on some kind of Microsoft-developed file system. Back in the 1980s and 1990s, though, things were different. You absolutely could not expect a floppy disk from one type of computer to work in another. That is, unless you had a magical three-format disk, as [RobSmithDev] explains.

The tri-format disk was a special thing. It was capable of storing data in Amiga, PC, and Atari ST formats. This was of benefit for cover disks—a magazine could put out content for users across all three brands, rather than having to ship multiple disks to suit different machines.

[RobSmithDev] started investigating by reading the tri-format disk with his DiskFlashback tool. The tool found two separate filesystems. The Amiga filesystem took up 282 KB of space. The second filesystem contained two folders—one labelled PC, the other labelled ST. The Atari ST folder contained 145KB of data, while the PC folder used 248 KB. From there, we get a breakdown on how the data for each format is spread across the disk, right down to the physical location of the data. The different disk formats of each system allowed data to be scattered across the disk such that each type of computer would find its relevant data where it expected it to be.

It’s a complex bit of disk engineering that allowed this trick to work, and [Rob] explains it in great detail. We love nitty gritty storage hacks around here. Video after the break.

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The End Of Ondsel And Reflecting On The Commercial Prospects For FreeCAD

November 12, 2024 by 106 Comments

Within the world of CAD there are the well-known and more niche big commercial players and there are projects like FreeCAD that seek to bring a OSS solution to the CAD world. As with other OSS projects like the GIMP, these OSS takes on commercial software do not always follow established user interactions (UX), which is where Ondsel sought to bridge the gap by giving commercial CAD users a more accessible FreeCAD experience. This effort is now however at an end, with a blog post by Ondsel core team member [Brad Collette] providing the details.

The idea of commercializing OSS is by no means novel, as this is what Red Hat and many others have done for decades now. In our article on FOSS development bounties we touched upon the different funding models for FOSS projects, with the Linux kernel enjoying strong commercial support. The trick is of course to attract such commercial support and associated funding, which is where the development on the UI/UX and feature set of the core FreeCAD code base was key. Unfortunately the business case was not strong enough to attract such commercial partners and Ondsel has been shutdown.

As also discussed on the FreeCAD forum, the Ondsel codebase will likely be at least partially merged into the FreeCAD code, ending for now the prospect of FreeCAD playing in the big leagues with the likes of AutoCAD.

Thanks to [Brian Harrington] for the tip.

WAV2VGM Plays Audio Via OPL3 Synthesis

November 12, 2024 by 9 Comments

Once upon a time, computers didn’t really have enough resources to play back high-quality audio. It took too much RAM and too many CPU cycles and it was just altogether too difficult. Instead, they relied upon synthesizing audio from basic instructions to make sounds and music. [caiannello] has taken advantage of this with the WAV2VGM project.

The basic concept is straightforward enough—you put a WAV audio file into the tool, and it spits out synthesis instructions for the classic OPL3 sound card. The Python script only works with 16-bit mono WAV files with a 44,100 Hz sample rate.

Amazingly, check the samples, and you’ll find the output is pretty recognizable. You can take a song with lyrics (like Still Alive from Portal), turn it into instructions for an OPL3, and it’s pretty intelligible. It sounds… glitchy and damaged, but it’s absolutely understandable.

It’s a fun little retro project that, admittedly, doesn’t have a lot of real applications. Still, if you’re making a Portal clone for an ancient machine with an OPL3 compatible sound chip, maybe this is the best way to do the theme song? If you’re working on exactly that, by some strange coincidence, be sure to let us know when you’re done!

Teaching Computers To Read — Sort Of

November 12, 2024 by 8 Comments

If you ask someone who grew up in the late 1970s or early 1980s what taught them a lot about programming, they’d probably tell you that typing in programs from magazines was very instructive. However, it was also very boring and error-prone. In fact, we’d say it was less instructional to do the typing than it was to do the debugging required to find all your mistakes. Magazines hated that and, as [Tech Tangents] shows us in a recent video, there were efforts to make devices that could scan barcodes from magazines or books to save readers from typing in the latest Star Trek game or Tiny Basic compiler.

The Cauzin Softstrip was a simple scanner that could read barcodes from a magazine or your printer if you wanted to do backups. As [Tech Tangents] points out, you may not have heard of it, but at the time, it seemed to be the future of software distribution.

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A Brief History Of Cyrix, Or How To Get Sued By Intel A Lot

November 12, 2024 by 29 Comments

In a new installment on computer history, [Bradford Morgan White] takes us through the sordid history of Cyrix, as this plucky little company created the best math co-processors (FasMath) and then a range of interesting x86-compatible CPUs that would give competing x86 CPUs a run for their money. Even though Cyrix played by the rules of licensing agreements, Intel would keep suing Cyrix repeatedly since the 1980s well into 1990s, for a total of seventeen times until Cyrix counter-sued for patent violations in May of 1997.

This case was settled between Cyrix and Intel, with a cross-licensing agreement established. Unfortunately these mounting legal costs and the stresses of keeping up with the competition (i.e. Intel) was proving too much and Cyrix was sold off to National Semiconductor, who wasn’t enthusiastic about competing with Intel. After this Cyrix got split up into Geode (sold to AMD) and Cyrix Technologies (sold to VIA). Interestingly, VIA’s x86 patent licenses and patents ended up being the foundation of Zhaoxin: a joint venture between VIA and Shanghai’s government which produces x86 CPUs for primarily the Chinese market.

We looked at the Cyrix Cx486DLC processor a while ago, and why their 386 upgrade options were perhaps not that great. Their later CPUs have however left a strong legacy that seems to endure in some way to this day.

Retrotechtacular: Color TV

November 12, 2024 by 20 Comments

We have often wondered if people dreamed in black and white before the advent of photography. While color pictures eventually became the norm, black and white TV was common for many years. After all, a TV set was a big investment, so people didn’t run out and buy the latest TV every year. Even if you did buy a new or used TV, a black and white model was much less expensive and, for many years, some shows were in black and white anyway. RCA, of course, wanted you to buy a color set. [PeriscopeFilm] has a 1963 promotional film from RCA extolling the virtues of a color set. The video also shows something about how the sets were made, as you can see below.

We aren’t sure we’d have led with the idea that color could save your life in this context, but we have to salute the melodrama. There is a good bit of footage of picture tube manufacturing, although the technical detail is — understandably — aimed at the general public.

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