Data Visualization And Aggregation: Time Series Databases, Grafana And More

If there’s one thing that characterizes the Information Age that we find ourselves in today, it is streams of data. However, without proper ways to aggregate and transform this data into information, it’ll either vanish into the ether or become binary blobs gathering virtual dust on a storage device somewhere. Dealing with these streams of data is thus essential, whether it’s in business (e.g. stock markets), IT (e.g. services status), weather forecasting, or simply keeping tracking of the climate and status of devices inside a domicile.

The first step of aggregating data seems simple, but rather than just writing it to a storage device until it runs out of space like a poorly managed system log, the goal here isn’t merely to record, but also to make it searchable. After all, for information transformation we need to be able to efficiently search and annotate this data, which requires keeping track of context and using data structures that lend themselves to this.

For such data aggregation and subsequent visualization of information on flashy dashboards that people like to flaunt, there are a few mainstream options, with among ‘smart home’ users options like InfluxDB and Grafana often popping up, but these are far from the only options, and depending on the environment there are much more relevant solutions.

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Chasing A Raspberry Pi Bottleneck

The Raspberry Pi has been used for many things over its lifetime, and we’re guessing that many of you will have one in perhaps its most common configuration, as a small server. [Thibault] has a Pi 4 in this role, and it’s used to back up the data from his VPS in a data centre. The Pi 4 may be small and relatively affordable, but it’s no slouch in computing terms, so he was extremely surprised to see it showing a transfer speed in bytes per second rather than kilobytes or megabytes. What was up? He set out to find the bottleneck.

We’re treated to a methodical step-through of all the constituent parts of the infrastructure between the data centre and the disk, and all of them show the speeds expected. Eventually, the focus shifts to the encryption he’s using, both on the USB disk connected to the Pi and within the backup program he’s using. As it turns out, while the Pi is good at many things, encryption is not its strong point. Some work with htop shows the cores maxed out as it tries to work with encrypted data, and he’s found the bottleneck.

To show just how useful a Pi server can be without the encryption, we’re using an early model to crunch a massive language corpus.

Header image: macrophile, CC BY 2.0.

The 2025 Iberian Peninsula Blackout: From Solar Wobbles To Cascade Failures

Some Mondays are worse than others, but April 28 2025 was particularly bad for millions of people in Spain and Portugal. Starting just after noon, a number of significant grid oscillations occurred which would worsen over the course of minutes until both countries were plunged into a blackout. After a first substation tripped, in the span of only a few tens of seconds the effects cascaded across the Iberian peninsula as generators, substations, and transmission lines tripped and went offline. Only after the HVDC and AC transmission lines at the Spain-France border tripped did the cascade stop, but it had left practically the entirety of the peninsula without a functioning power grid. The event is estimated to have been the biggest blackout in Europe ever.

Following the blackout, grid operators in the affected regions scrambled to restore power, while the populace tried to make the best of being plummeted suddenly into a pre-electricity era. Yet even as power gradually came back online over the course of about ten hours, the question of what could cause such a complete grid collapse and whether it might happen again remained.

With recently a number of official investigation reports having been published, we have now finally some insight in how a big chunk of the European electrical grid suddenly tipped over.

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Behind RadioShack’s Cheapest Computer

In the 1980s, there was a truly staggering amount of choice for a consumer looking to purchase a home computer. On the high end, something like an Apple Lisa, a business-class IBM PC, or a workstation from Sun Microsystems could easily range from $6,000 to $20,000 (not adjusted for inflation). For the time, these mind-blowing prices might have been worth the cost, but for those not willing to mortgage their homes for their computing needs, there were also some entry-level options. One of these was the Sinclair ZX-80, which was priced at an astounding $100, which caused RadioShack to have a bit of a panic and release this version of the TRS-80 computer to compete with it.

As [David] explains in his deep dive into this somewhat obscure machine, the TRS-80 MC-10 was a commercial failure, although not for want of features. It had a color display, a chicklet keyboard, and 4K of RAM, which were all things that the ZX-80 lacked.

Unfortunately, it also had a number of drawbacks compared to some of its other contemporaries that made consumers turn away. Other offerings by Commodore, Atari, Texas Instruments, and even RadioShack themselves were only marginally more expensive and had many more features, including larger memory and better storage and peripheral options, so most people chose these options instead.

The TRS-80 MC-10 is largely a relic of the saturated 80s home computer market. It’s drop in price to below $50, and the price competition between other PC manufacturers at the time was part of the reason for the video game crash of the 1980s, and even led to Steve Jobs getting fired from Apple. There’s not a huge retro scene for these machines either, although there is at least one game developer you can see in the video below from [Spriteworx]. If you want to experiment with some of the standard TRS-80 software, there are emulators that have everything you need.

Thanks to [Stephen] for the tip!

A clear acrylic cylinder is shown, inside of which plants are visible. There is mist inside the tube, and LEDs light it from above. A black plastic cap to the tube is visible.

Preserve Your Plants With An Automated Terrarium

For those of us who aren’t blessed with a green thumb and who are perhaps a bit forgetful, plants can be surprisingly difficult to keep alive. In those cases, some kind of automation, such as [Justin Buchanan]’s Oasis smart terrarium, is a good way to keep our plants from suffering too much.

The Oasis has an ultrasonic mister to water the plants from a built-in tank, LED grow lights, fans to control airflow, and a temperature and humidity sensor. It connects to the local WiFi network and can set up recurring watering and lighting schedules based on network time. Most of the terrarium is 3D-printed, with a section of acrylic tubing providing the clear walls. Before installing the electronics, it’s a good idea to waterproof the printed parts with low-viscosity epoxy, particularly since the water tank is located at the top of the terrarium, where a leak would drip directly onto the control electronics.

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Switching From Desktop Linux To FreeBSD

People have been talking about switching from Windows to Linux since the 1990s, but in the world of open-source operating systems, there is much more variety than just the hundreds of flavors of Linux-based operating systems today. Take FreeBSD, for example. In a recent [GNULectures] video, we get to see a user’s attempt to switch from desktop Linux to desktop FreeBSD.

The interesting thing here is that both are similar and yet very different, mainly owing to their very different histories, with FreeBSD being a direct derivative of the original UNIX and its BSD derivative. One of the most significant differences is probably that Linux is just a kernel, with (usually) the GNU/Hurd userland glued on top of it to create GNU/Linux. GNU and BSD userland are similar, and yet different, with varying levels of POSIX support. This effectively means that FreeBSD is a singular OS with rather nice documentation (the FreeBSD handbook).

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Break The Air Gap With Ultrasound

In the world of information security, much thought goes into ensuring that no information can leave computer networks without expressly being permitted to do so. Conversely, a lot of effort is expended on the part of would-be attackers to break through whatever layers are present. [Halcy] has a way to share data between computers, whether they are networked or not, and it uses ultrasound.

To be fair, this is more of a fun toy than an elite exploit, because it involves a web interface that encodes text as ultrasonic frequency shift keying. Your computer speakers and microphone can handle it, but it’s way above the human hearing range. Testing it here, we were able to send text mostly without errors over a short distance, but at least on this laptop, we wouldn’t call it reliable.

We doubt that many sensitive servers have a sound card and speakers installed where you can overhear them, but by contrast, there are doubtless many laptops containing valuable information, so we could imagine it as a possible attack vector. The code is on the linked page, should you be interested, and if you want more ultrasonic goodness, this definitely isn’t the first time we have touched upon it. While a sound card might be exotic on a server, a hard drive LED isn’t.