Author: Al Williams

4348 Articles

Behind The X86 Pipeline Curtain

June 19, 2023 by 12 Comments

We’ve often heard that modern x86 CPUs don’t really execute x86 instructions. Instead, they decode them into RISC instructions that are easier to schedule, pipeline, and execute. But we never really looked into that statement to see if it is true. [Fanael] did, though, and the results are very interesting.

The post starts with a very simple loop containing four instructions. In a typical RISC CPU — RISC-V — the same loop requires six instructions. However, a modern CPU is likely to do much more than just blindly convert one instruction set to another.

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Better Antennas Via Annealing (Simulated)

June 18, 2023 by 26 Comments

If you want to simulate a tic-tac-toe game, that’s easy. You can evaluate every possible move in a reasonable amount of time. Simulating antennas, however, is much harder. [Rosrislav] has been experimenting with using simulated annealing to iterate antenna designs, and he shares his progress in a recent blog post.

For many problems, it simply isn’t possible to try all possible inputs to determine what provides the “best” result. Instead of trying every single input or set of inputs, you can try random ones and discard all but the best guesses. Then you make small changes and try again. The only problem is that the algorithm may lock in on a “local maximum” — that is, a relatively high value that isn’t the highest because it forms a peak that isn’t the highest peak. Or, if you are looking for a minimum, you may lock on to a local minimum — same thing.

To combat that, simulated annealing works like annealing a metal. The simulation employs a temperature that cools over time. The higher the temperature, the more likely large changes to the input are to occur.

The Python program uses the PyNEC package to provide simulation. The program sets up random antenna lengths and finds the projected gain, attempting to optimize for maximum gain.

The post is long on code and short on details, so you will probably want to read the Python source to see exactly what it is doing. But it could probably serve as a template to do other simulated annealing simulations for other antennas or anything you had a simulation engine to evaluate.

Several techniques allow you to optimize things that are too hard to search exhaustively, and we’ve talked about simulated annealing and genetic algorithms before. However, lately, we’ve been more interested in annealing 3D prints.

Detecting Meteors With SDR

June 18, 2023 by 10 Comments

The simplest way to look for meteors is to go outside at night and look up — but it’s not terribly effective. Fortunately, there’s a better way: radio. With a software-defined radio and a little know-how from [Tech Minds], you can easily find them, as you can see in the video below.

This uses the UK meteor beacon we’ve looked at before. The beacon pushes an RF signal out so you can read the reflections from meteors. If you are too far from the beacon, you may need a special antenna or you might have to find another beacon altogether. We know of the Graves radar in France and we have to wonder if you couldn’t use some commercial transmitter with a little experimentation.

[Tech Minds] has some practical tips to share if you want to try doing it yourself. If you want to see what a detected meteor looks like, you can visit the UK beacon’s gallery page.

We saw another presentation on the UK beacon earlier this year. Using commercial transmitters sounds like it might be easy, but apparently, it isn’t.

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If Not Ethernet…

June 17, 2023 by 66 Comments

It is hard to imagine today, but there was a time when there were several competing network technologies. There was Ethernet, of course. But you could also find token ring, DEC Net, EcoNet, and ARCNet. If you’ve never dug into ARCNet, [Retrobytes] has a comprehensive history you can watch that will explain it all.

Like token ring, ARCNet used a token-passing scheme to allow each station on the network to take turns sending data. Unlike token ring and Ethernet, the hardware setup was much less expensive. Along the way, you get a brief history of the Intel 8008 CPU, which, arguably, started the personal computer revolution.

Like most networking products of the day, ARCNet was proprietary. However, by the late 1980s, open standards were the rage, and Ethernet took advantage. Up until Ethernet was able to ride on twisted pairs, however, it was more expensive and less flexible than ARCNet.

The standard used RG-62/U coax and either passive or active hubs in a star configuration. The coax could be up to 2,000 feet away, so very large networks were feasible. It was also possible to share the coax with analog videoconferencing.

Looking back, ARCNet had a lot to recommend it, but we know that Ethernet would win the day. But [Retrobytes] explains what happened and why.

If you missed “old-style Ethernet,” we can show you how it worked. Or, check out EcoNet, which was popular in British schools.

Intel To Ship Quantum Chip

June 17, 2023 by 29 Comments

In a world of 32-bit and 64-bit processors, it might surprise you to learn that Intel is releasing a 12-bit chip. Oh, wait, we mean 12-qubit. That makes more sense. Code named Tunnel Falls, the chip uses tiny silicon spin quantum bits, which Intel says are more advantageous than other schemes for encoding qubits. There’s a video about the device below.

It is a “research chip” and will be available to universities that might not be able to produce their own hardware. You probably aren’t going to find them listed on your favorite online reseller. Besides, the chip isn’t going to be usable on a breadboard. It is still going to take a lot of support to get it running.

Intel claims the silicon qubit technology is a million times smaller than other qubit types. The size is on the order of a device transistor — 50 nanometers square — simplifying things and allowing denser devices. In silicon spin qubits, information resides in the up or down spin of a single electron.

Of course, even Intel isn’t suggesting that 12 qubits are enough for a game-changing quantum computer, but you do have to start somewhere. This chip may enable more researchers to test the technology and will undoubtedly help Intel accelerate its research to the next step.

There is a lot of talk that silicon is the way to go for scalable quantum computing. It makes you wonder if there’s anything silicon can’t do? You can access today’s limited quantum computers in the proverbial cloud.

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Clock Project Doesn’t Require A Decision

June 17, 2023 by 12 Comments

You decide to build a clock. The first thing you have you determine if it is going to be digital or analog. Or is it? If you build [Ivanek240267]’s clock, you can have both.

The digital portion uses an OLED display. The analog portion contains two rings of smart LEDs. The WiFi configuration is always an issue in projects like this, and this clock also offers options. In addition, the Raspberry Pi Pico-based clock also sets itself via NTP.

You can, of course, compile the WiFi credentials into the code, and assuming you don’t plan on changing networks, that’s fine. But if you’re in a more dynamic situation, the clock can also read its configuration from a memory card.

The analog clock uses colors. The green LEDs represent quarter hours. The blue LEDs are for minutes, while the red ones are full hours. Of course, reading the OLED doesn’t require any special interpretation.

When debugging, the timing doesn’t drive the smart LEDs. That means if you need to work on that part of the code, you won’t be able to count on debugging support.

We’ve mentioned before that digital clocks are all analog, anyway. If you want to use fewer LEDs, you can get by with only five.

Thermal Camera Reviewed

June 16, 2023 by 13 Comments

We keep thinking about buying a better thermal camera, as there are plenty of advantages. While [VoltLog’s] review of the Topdon TC002 was interesting though, it has a connector for an iPhone. Even if you aren’t on Android, there is a rumor that Apple may (or may be forced to) change connectors which will make it more difficult to connect. Of course, there will be adapters, and you can get a USB C version of the same camera.

Technically, the camera is pretty typical of other recent cameras in this price range, and they probably all use the same image sensor. The camera provides 256×192 images.

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