The Rise And Fall Of Silicon Graphics

April 8, 2024 by Maya Posch 55 Comments

Maybe best known as the company which brought a splash of color to corporate and scientific computing with its Indigo range of computer systems, Silicon Graphics Inc. (later SGI) burst onto the market in 1981 with what was effectively one of the first commercial graphics operations accelerator with the Geometry Engine. SGI’s founder – James Henry Clark was quite possibly as colorful a character as the company’s products, with [Bradford Morgan White] covering the years leading up to SGI’s founding, its highlights and its eventual demise in 2009.

The story of SGI is typical of a start-up that sees itself become the market leader for years, even as this market gradually changes. For SGI it was the surge in commodity 3D graphics cards in the 1990s alongside affordable (and cluster-capable; insert Beowulf cluster jokes here) server hardware that posed a major problem. Eventually it’d start offering Windows NT workstations, drop its MIPS-based systems in a shift to Intel’s disastrous Itanium range of CPUs and fall to the last-ditch effort of any struggling company: a logo change.

None of this was effective, naturally, and ultimately SGI would file (again) for Chapter 11 bankruptcy in 2009, with Rackable Systems snapping up its assets and renaming itself to SGI, before getting bought out by HPE and sunsetting SGI as a brand name.

Ultimate Power: Lithium-Ion Packs Need Some Extra Circuitry

April 8, 2024 by Arya Voronova 19 Comments

A LiIon pack might just be exactly what you need for powering a device of yours. Whether it’s a laptop, or a robot, or a custom e-scooter, a CPAP machine, there’s likely a LiIon cell configuration that would work perfectly for your needs. Last time, we talked quite a bit about the parameters you should know about when working with existing LiIon packs or building a new one – configurations, voltage notations, capacity and internal resistance, and things to watch out for if you’re just itching to put some cells together.

Now, you might be at the edge your seat, wondering what kind of configuration do you need? What target voltage would be best for your task? What’s the physical arrangement of the pack that you can afford? What are the safety considerations? And, given those, what kind of electronics do you need?

Picking The Pack Configuration

Pack configurations are well described by XsYp:X serial stages, each stage having Y cells in parallel. It’s important that every stage is the same as all the others in as many parameters as possible – unbalanced stages will bring you trouble.

To get the pack’s nominal voltage, you multiply X (number of stages) by 3.7 V, because this is where your pack will spend most of its time. For example, a 3s pack will have 11.1 V nominal voltage. Check your cell’s datasheet – it tends to have all sorts of nice graphs, so you can calculate the nominal voltage more exactly for the kind of current you’d expect to draw. For instance, the specific cells I use in a device of mine, will spend most of their time at 3.5 V, so I need to adjust my voltage expectations to 10.5 V accordingly if I’m to stack a few of them together.

Now, where do you want to fit your pack? This will determine the voltage. If you want to quickly power a device that expects 12 V, the 10.5 V to 11.1 V of a 3s config should work wonders. If your device detects undervoltage at 10.5V, however, you might want to consider adding one more stage.

How much current do you want to draw? For the cells you are using, open their spec sheet yet again, take the max current draw per cell, derate it by like 50%, and see how many cells you need to add to match your current draw. Then, add parallel cells as needed to get the capacity you desire and fit the physical footprint you’re aiming for. Continue reading “Ultimate Power: Lithium-Ion Packs Need Some Extra Circuitry” →

1950s Switching Power Supply Does It Mechanically

April 8, 2024 by Al Williams 26 Comments

When you hear about a switching power supply, you think of a system that uses an inductor and a switch to redistribute energy from the input to the output. But the original switching power supply was the vibrator supply, which was common in automotive applications back in the middle part of the last century. [Mr. Carlson] has a 1950s-era example of one of these, and he invites us to watch him repair it in the video below.

Most of the vibrator supplies we’ve seen have been built into car radios, but this one is in a box by itself. The theory is simple. A DC voltage enters the vibrator, which is essentially a relay that has a normally-closed contact in series with its coil. When current flows, the relay operates, breaking the contact. With no magnetic field, the springy contact returns to its original position, allowing the whole cycle to repeat.

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Heating Mars On The Cheap

April 8, 2024 by Lewin Day 78 Comments

Mars is fairly attractive as a potential future home for humanity. It’s solid, with firm land underfoot. It’s able to hang on to a little atmosphere, which is more than you can say about the moon. It’s even got a day/night cycle remarkably close to our own. The only problem is it’s too darn cold, and there’s not a lot of oxygen to breathe, either.

Terraforming is the concept of fixing problems like these on a planet-wide scale. Forget living in domes—let’s just make the whole thing habitable!

That’s a huge task, so much current work involves exploring just what we could achieve with today’s technology. In the case of Mars, [Casey Handmer] doesn’t have a plan to terraform the whole planet. But he does suggest we could potentially achieve significant warming of the Red Planet for $10 billion in just 10 years. Continue reading “Heating Mars On The Cheap” →

Fortran And WebAssembly: Bringing Zippy Linear Algebra To NodeJS & Browsers

April 8, 2024 by Maya Posch 15 Comments

With the rise of WebAssembly (wasm) it’s become easier than ever to run native code in a browser. As mostly just another platform to target, it would be remiss if Fortran was not a part of this effort, which is why a number of projects have sought to get Fortran supported on wasm.

For the ‘why’, [George Stagg] makes the point that software packages like BLAS and LAPACK for Fortran are still great for scientific computing, while the ‘how’ is a bit more hairy, but getting better courtesy of the still-in-development LLVM front-end for Fortran (flang-new). Using it for wasm is not straightforward yet, due to the lack of a wasm32 target, but as [George] demonstrates, this is easily patched around.

We reported on Fortran and wasm back in 2016, with things having changed somewhat in the intervening eight years (yes, that long). The Fortran-to-C translator utility (f2c) is effectively EOL, while LFortran is coming along but still missing many features. The Dragonegg GCC-frontend-for-LLVM project was the best shot in 2020 for Fortran and WebAssembly, but obsolete now. Classic Flang has been in LLVM for a while, but is to be replaced with what is now called flang-new. The wish by [George] is now to find a way to get his patched flang-new code for wasm support into the project.

In the article, the diff for patching the flang-new toolchain to target wasm is provided. During compilation of the standard Fortran runtime it was then found that the flang-new code assumes that target system sizeof() results are identical to those of the host system, which of course falls flat for wasm32. One more patch (or hardcoded hack, rather) later the ‘Hello World’ example in Fortran was up and running, clearing the way to build the BLAS (Basic Linear Algebra Subprograms) and LAPACK (Linear Algebra Package) libraries and create a few example projects in Fortran-for-wasm32 which uses them.

The advantage of being able to use extremely well-optimized software packages like these when limited to a browser environment should be obvious, in addition to the benefit of using existing codebases. It is certainly [George]’s hope that flang-new will soon officially support wasm (32 and 64-bit) as targets, and he actively seeks help with making this a reality.

KanaChord Is A Macro Pad For Japanese Input

April 8, 2024 by Kristina Panos 13 Comments

There are various situations that warrant additional keyboards on your desk, and inputting a second language is definitely a good one. That’s the idea behind KanaChord, which generates Unicode macros to render Japanese Kana characters using chords — pressing multiple keys at once as you would on a piano.

The Japanese writing system is made up of Kanji (Chinese characters), Hirigana, and Katakana. Without going into it too much, just know that Hirigana and Katakana are collectively known as the Kana, and there’s a table that lays out the pairing of vowels and consonants. To [Mac Cody], the layout of the Kana table inspired this chording keyboard.

Continue reading “KanaChord Is A Macro Pad For Japanese Input” →

Fixing An Expensive Smart Toaster Is Worth The Time

April 7, 2024 by Al Williams 49 Comments

There was a time when the simplest and cheapest kitchen appliance you could think of was a toaster. Some nichrome wire, a spring, and a mechanical thermostat were all you needed. Those days are gone and today’s toasters are full of special features, network connections, and fancy cases.

Take [boilerbot]’s Breville die-cast smart toaster. The four-slice model is upwards of $200. As Star Trek’s [Mr. Scott] said, “The more they overthink the plumbing, the easier it is to stop up the drain.” That seems to be the case here. The toaster failed and while [boilerbot] did fix it, he got lucky. He mentions that if the damage had been lower in the toaster, getting to it would have been nearly impossible.

Continue reading “Fixing An Expensive Smart Toaster Is Worth The Time” →