North Korea’s Tech Control: Red Star OS and Surveillance Smartphones | July 13 2025, 00:58

In the latest video about North Korea from Lankov, I heard something interesting: a device owner cannot open someone else’s file, whether on a computer or on a phone, unless it is signed with a special digital signature from the government. Intrigued, I researched the details for myself and for you.

On their phones, they use a modified old “KitKat” Android (2013), and on computers—a modified Fedora Linux, Red Star OS 3, with a shell that mimics the macOS interface from Apple (the previous one mimicked Windows XP). It is said that this design choice may have been influenced by the fact that leader Kim Jong Un was seen with an iMac on his desk, and apparently, he said make it the same.

North Korean smartphones are equipped with hidden surveillance features that automatically take screenshots every five minutes, storing them in a secret folder accessible only to authorities, not the user. According to other sources, screenshots are taken when applications start, apparently pseudo-randomly. There is also censorship: if you type “South Korea” (남조선) in any app, the system automatically replaces it with “puppet state” (괴뢰국가). One hundred percent of the phones are obviously Chinese, modified by China for Korea. By the way, the collected screenshots are accessible to users, but they cannot be deleted. This application, Trace Viewer, is clearly created to remind users: everything that they do on the tablet or phone can be known to the government.

All media content in Red Star OS, including documents, images, audio and video files, is automatically marked with a watermark containing a unique serial number of the hard drive, which allows authorities to track its origin and distribution. That is, you cannot take a photo and send it to someone, because it will either just not open on that phone, or, apparently, in rare cases, if sharing is allowed, in the new place there will be traces of both who is the author of the photo and who is the next owner. But this is underdeveloped, and direct file sharing is still limited. You can only use it yourself. Of course, nothing can be deleted from the phone without a trace. It is not allowed to have more than one device per person (seems to apply separately to a tablet and a phone).

North Korean mobile devices use a strict system of digital signatures (NATISIGN for government-approved content and SELFSIGN for content created on the device), which means that any file without these signatures cannot be opened at all. The system of signatures and signature verification is at the level of the operating system, not applications. This applies to all files that people create, both on phones and on computers. I see a huge number of edge cases here, but there is little information and no one to ask.

The penalties for accessing unauthorized foreign media, such as K-pop or South Korean dramas, are extremely harsh. If an “undesirable file” is found on a CD inserted into a computer with Red Star OS, the system will eject the CD, record the path to the file, display a graphical warning, take screenshots, and then forcefully reboot the system after 1000 seconds.

North Korea manages a national intranet network called Kwangmyong, “walled garden,” which is completely isolated from the global internet and is available to most citizens only for government-approved websites and email systems.

When you first launch the browser Naenara (based on Firefox 3.5), the default homepage is the IP address “10.76.1.11.” That is, their internet is essentially an intranet.

Exploring the Intricacy of a 3200-Wire Copper Telephone Cable | July 12 2025, 15:11

Copper telephone trunk cable. Here are 3,200 (!) color-coded wires each 0.4 mm in diameter. Such cables are usually made up of twisted pairs (each pair consists of two wires), and 3,200 wires mean 1,600 pairs. The entire cable has a diameter of 9 cm and is produced in 250-meter segments. These segments need to be joined together, and then the ends connected to equipment. So, each of the 3,200 cores is carefully stripped and connected to the corresponding wire of the next segment. Probably a very entertaining activity.

Exploring the Technological Marvels of Tesla’s Full Self-Driving Capabilities | July 11 2025, 03:59

I read various engineering blogs about Tesla’s autopilot (FSD) — simply because for the last month and a half I’ve been almost constantly riding as if in a taxi — you set the destination and hardly ever need to intervene, the car travels from point A to point B completely independently. This is certainly the future.

Such systems exist not only at Tesla. For example, Mercedes has one (Drive Pilot). Others only help in traffic jams at best. Though Tesla seems to be the only one that works on all roads.

So, returning to engineering curiosities. Tesla has an AI model production on its “farm” called Dojo — an exaFLOP supercomputer on Tesla chips. Videos from cameras are fed into it, and it trains models that are then sent out for autonomous operation across the entire fleet of Tesla cars.

The FSD architecture comprises about 48 specialized neural networks, trained on Dojo, which together form about 1,000 different prediction tensors. Tesla is gradually moving from modular networks (object recognition + planning) to end-to-end training — directly converting video frames into steering trajectory/action. This is akin to a “black box” — the neural network learns directly from human behavior, without manual tuning of knobs; an extremely cool engineering solution, but, I suspect, complex to debug.

By the way, it is claimed that Tesla has switched from C++ to Python. And that this shift to end-to-end training has made 300,000 lines of C++ code unnecessary, where various corner cases and rules for resolving different scenarios were accounted for — now it’s at the model level.

Tesla has abandoned radar and ultrasonics, switching to purely camera solutions (Vision Only) with “Hardware 4” (HW4, FSD Computer 2): 16 GB RAM, 256 GB flash memory, performance 3–8× higher than HW3.

Assess the performance: 22 milliseconds to create a 3D scene with cars, pedestrians, cyclists around — information is collected from 8 cameras 36 times per second.

85 ms for the entire cycle from receiving the image to changing the plan and commands to the wheels. Fantastic!

More than 4 million Teslas on the roads collect data daily, and in the FSD Beta version, more than a billion miles of autonomous driving have been recorded. This “live” dataset is used to train networks on the most real-world scenarios, including rare “edge-case” incidents (strange accidents, road conditions, etc.).

In June 2025, Tesla for the first time delivered a Model Y from the factory in Austin to a customer’s home without a driver or remote operator — fully autonomously. This is very cool.

The Vision network not only analyzes the current frame but also stores features from previous ones (at a distance of ≈1 m). This allows it to remember recently crossed markings/signs, even if they have already left the field of view – very similar to human memory.

Awaiting the Next Big Thing from Boston Dynamics | July 10 2025, 20:09

I’ve been thinking, it’s been a while since there was an exciting video from Boston Dynamics. Remember, each one used to create quite a stir online. I checked their channel. And it looks good. Hundreds of millions in investments from the Pentagon/US Department of Defense suggest that it won’t stop at drones.

https://youtu.be/I44_zbEwz_w?si=51szmPYzdYtBGs6X

https://youtu.be/I44_zbEwz_w?si=51szmPYzdYtBGs6X

Treasures in Translation: A Glimpse into Rare Russian Reprints | July 09 2025, 01:27

Nadia from Russia just brought me three books I ordered. “The Art of Color” by J. Itten, “Americans and Everyone Else” by I. Kurilla, and this one, Holodkovsky’s commentary on his translation of Faust. Interestingly, it seems that these commentaries are not available in Russian.. to be more precise.. in modern Russian. There is a reprint of the original 1914 edition, created based on a high-resolution electronic copy that was manually cleaned and processed, preserving the structure and spelling of the original edition, and it seems it was not translated into modern Russian. However, there are no difficulties in reading the reprint.

The Paradox of Symmetry: Beauty, Boredom, and the Brain | July 06 2025, 23:13

Probably not just for me a contradictory perception of symmetry exists. On one hand, symmetry is perceived as a sign of harmony and stability because the brain processes and recognizes organized forms more quickly, which historically could have aided survival. Logically, it should be associated with beauty, health, and predictability, giving a sense of security.

It’s written that with one or two alcoholic drinks, symmetrical objects become even more attractive. “In a pilot study (Elena Karakashevska) involving 13 social drinkers, researchers were surprised to find that alcohol apparently enhances the brain’s response to symmetry.” The study also concluded that people look better after consuming alcohol 🙂 This reminds me of a joke about two friends, when one says, “Now we’ll go to the girls, one is alright – for me, and the other one is a bit ugly, but you drink some vodka — and she will be fine,” and when they arrive, they ring the doorbell, two women are on the doorstep, and the second says: “Oh, I can’t drink that much!”

On the other hand, excessive symmetry and monotony can cause boredom and irritation as the brain seeks stimulation and novelty. For example, imagine a symmetrical tattoo on someone. Can you picture one that you aesthetically prefer over an asymmetrical one?

Personally, I like small deviations and asymmetry, which make images lively and interesting. A certain balance of order and chaos. Pure symmetry seems very boring to me.

Started googling on the topic. “Japanese don’t like symmetry. If a vase on the table is in the middle, they will automatically move it to the edge of the table. Why? Symmetry as completion, as finitude, as repetition is uninteresting. For instance, the dishes on a Japanese table (dinnerware) will definitely have different patterns, different colors.”

Do you like symmetry?

Exploring the Bubble Method of River Level Measurement at the Potomac | July 06 2025, 19:38

How would you measure the water level in a river? A float? A pressure sensor? Something else? Yesterday, I discovered how it’s done here on the Potomac, and it turned out to be not at all what I had imagined. The USGS engineers are great—they educate passersby by posting a diagram of the operation.

A tube is lowered into the river through which air is supplied in bubbles (through a bubble orifice). A special pressure sensor (Pressure Transducer) measures the air pressure in the tube that is necessary to release the bubbles from it. The higher the water level in the river, the more pressure is required to push the air into the water—because the air pressure in the tube is directly related to the depth of the water (according to Pascal’s law). The bubble method works well even if there is floating debris or ice in the river, which may interfere with other sensors (such as ultrasonic ones). Since the sensor does not contact the water, it always remains dry and clean. Additionally, to prevent data distortion, the system includes an air dryer (Air Dryer), which removes moisture from the air and prevents condensation.

The accuracy of such systems is 1-2 cm in water level for rivers with shallow depths.

Interestingly, the readings are transmitted not through the mobile network, but via satellite.