Peering Into a Running Brain: SDRAM Refresh Analyzed from Userspace

Over on the Cloudflare blog, [Marek] found himself wondering about computer memory, as we all sometimes do. Specifically, he pondered if he could detect the refresh of his SDRAM from within a running program. We’re probably not ruining the surprise by telling you that the answer is yes — with a little more than 100 lines of C and help from our old friend the Fast Fourier Transform (FFT), [Marek] was able to detect SDRAM refresh cycles every 7818.6 ns, lining right up with the expected result.

The “D” in SDRAM stands for dynamic, meaning that unless periodically refreshed by …read more

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E-ink Typewriter Is Refreshingly Slow

It’s pretty hard to use the internet to complete a task without being frequently distracted. For better or worse, there are rabbit holes at every turn and whilst exploring them can be a delight, sometimes you just need to focus on a task at hand. The solution could be in the form of distraction-blocking software, razor-sharp willpower, or a beautifully crafted modern “typewriter”. The constraint and restriction of a traditional typewriter appealed to [NinjaTrappeur], but the inability to correct typos and share content online was a dealbreaker. A hybrid was the answer, with a mechanical keyboard commanding an E-ink display …read more

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Chasing the Electron Beam at 380,000 FPS

Analog TV is dead, but that doesn’t make it any less awesome. [Gavin and Dan], aka The Slow Mo Guys recently posted a video about television screens. Since they have some incredible high-speed cameras at their disposal, we get to see the screens being drawn, both on CRT and more modern LCD televisions.

Now we all know that CRTs draw one pixel at a time, drawing from left to right, top to bottom. You can capture this with a regular still camera at a high shutter speed. The light from a TV screen comes from a phosphor coating pained on …read more

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