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Notes on telephone jacks, and what a PBX is

quorten

2018-12-10

Categories: random-software   raspberry-pi  
Tags: random-software   raspberry-pi  

Okay, so when searching for information on telephone jacks, I learned some interesting things to take note of.

• “Registered jacks” are very specific to the implementation of an installed jack use.

• RJ45 is technically an incorrect label for Ethernet jacks because Ethernet jacks are unkeyed 8P8C connectors.

• If you care mainly about the mechanical and electrical specifications of the plug, then the 6P6C, 6P4C, 6P2C, etc. names are the correct ones to be searching for. Nevertheless, given the frequent incorrect usage that has emerged in relation to Ethernet connectors, you might as well also try searching for the RJ jack colloquialisms.

• PBX = Private Branch Exchange, which refers to a telephone switching system installed in a business. Nowadays with VoIP, a PBX is easy for anyone to setup.

20181209/https://en.wikipedia.org/wiki/Registered_jack
20181209/https://en.wikipedia.org/wiki/Business_telephone_system
20181209/https://en.wikipedia.org/wiki/Modular_connector

Digestive system microbes and immigrants

quorten

2018-12-09

Categories: random  
Tags: random  

This is interesting. I’ve read about this before, but didn’t take any notes on this thus yet. Studying digestive system microbe changes in immigrants? First of all, people outside the U.S. in developing and third world countries tend to have a greater diversity in gut bacteria than U.S. people and people of western diets. Now, here’s the interesting part. After immigration, after only 6 to 9 months, the immigrant’s gut bacteria changes drastically. Most of the native bacteria they had is lost, and they acquire the new bacteria that is more common among western diets. The process continues on even for 10 years. For the children of immigrants, the shift is more drastic. Shifting to a diet of western foods somewhat explains the change in microbes, but it doesn’t completely explain it.

Additionally, one peculiar association with studying immigrants is that in their original conditions, obesity levels are very low, but after migrating, obesity becomes a larger problem. There is still a lot unknown here, but it appears from the diagram in the article that what happens is that in the beginning, obesity is less of a problem for immigrants than it is for westerners, but after immigrating, it becomes just as much of a problem for them as it is for westerners.

20181209/https://cse.umn.edu/college/news/immigration-united-states-changes-persons-microbiome

Pollinator decline, prairies, wetlands, bobcat, golden toad

quorten

2018-12-09

Categories: random  
Tags: random  

Pollinator decline. Yeah, I saw that in my previous reference to the defaunation article, but didn’t read through it in more detail. So now I’m investigating it more.

Wow, there has been quite a drastic decline in bees in the past few decades. Hive failure rates up to 50% in some regions? 6% decline of flying biomass a year? What are the causes of the drops?

• Pesticides

• Rapid transfer of pollinator species diseases around the world

• Loss of habitat and forage

• Air pollution

• Changes in seasonal behavior due to global warming

• Artificial lighting at night. Increased use of blue light at night in recent years is perhaps the most noteworthy aspect. The distinctive yellow orange color of sodium vapor street lighting of times past, besides looking curiously interesting to humans, was technically energy efficient, low luminosity (orange has a high perceptive brightness to humans), and interfered minimally with animal night life. Nowadays, the switchover to bluish-white LED street lighting was motivated primarily for energy efficiency purposes, to be even more energy efficient than the sodium vapor lights of times past. Only in hindsight are people realizing the negative effects of the switchover. But, by contrast, urban city centers have long been favoring whiter light upon the belief that it is brighter and safer for the human populance.

But, come on! Suffice it to say, many of the mitigations are quite simple to commence upon. Switching to pesticides that are not harmful to pollinators, for example. Also, another interesting one was planting wild flowers at the borders of grain farms that otherwise provide very little nectar that is essential to bumble bees.

20181208/https://en.wikipedia.org/wiki/Pollinator_decline

Read on →

Different ways to indicate web page language

quorten

2018-12-08

Categories: random-software  
Tags: random-software  

First impetus for the web search. Google Chrome thinks your web page is in Danish? What information does the Internet have for why this may be the case? Well, I didn’t really find out any useful information on that front, but I did find this StackOverflow page with useful information on different ways of setting the language on your page.

• HTTP Headers: Content-Language

• HTML meta: http-equiv Content-Language field, Google’s preferred method

• HTML/XML lang fields

20181208/DuckDuckGo chrome thinks translate from danish
20181208/https://stackoverflow.com/questions/2467454/why-does-chrome-incorrectly-determine-page-is-in-a-different-language-and-offer

Automatic smartphone test lab?

quorten

2018-12-07

Categories: random  
Tags: random  

Automatic smartphone test lab?

Oh, so this is interesting. Here, I’m seeing results for what an automatic smartphone test lab looks like for the sake of hardware manufacturers. I was first thinking mainly about some of the automatic test labs set up for software developers like Facebook.

So, some of the interesting things they have setup:

• Camera tests inside of realistic 3D environments

• Anechoeic chamber acoustic tests, holding the smartphone at a variety of weird angles.

• Sitting test, with authentic jean patterning on the apparatus.

• Full water submersion tests.

• Testing inside a variety of climates

• Drop tests, spin tests

• Testing for RF interference using elaborate setups in an “RF anechoeic chamber.”

20181207/DuckDuckGo smartphone automatic test lab
20181207/https://www.techspot.com/news/77492-look-inside-samsung-lab-testing-galaxy-smartphones-wearables.html
20181207/https://www.wired.co.uk/article/how-phones-are-tested-huawei

CCN is yet another stalled new network protocol project

quorten

2018-12-06

Categories: random-software  
Tags: random-software  

Really, I’m wondering, what is the current status of content-centric networking? It’s been a really long time since I’ve heard of any updates on it.

20181206/DuckDuckGo content centric networking
20181206/https://en.wikipedia.org/wiki/Content_centric_networking

It’s interesting that the Wikipedia article does not have any talk page.

Okay, so let’s find the GitHub project for it, as it is not linked from Wikipedia.

20181206/DuckDuckGo ccnx

Navigating to the official CCN project, the first thing I see is that it has a redirect note to the modern project that replaced it.

20181206/https://github.com/ProjectCCNx/ccnx

Yet, looking at this “more modern” GitHub project, the GitHub project was last updated two years ago, in 2016. There are only 19 forks of this project. There you go, I think that says it all.

20181206/https://github.com/PARC/CCNx_Distillery

So, is there any information on the discontinuation of CCN? Unfortunately, it doesn’t look like it. It’s just yet another one of those projects that comes in with a great publicity announcement, but slips away simply by being slowly forgotten.

20181206/DuckDuckGo ccn is dead

Wow, this is really interesting. The title says it all: Over 1,000 cryptocurrencies are dead projects. I guess, you can say, perhaps this is one of the things that most sets cryptocurrency apart from typical fiat currency. Even more so, what sets cryptocurrency apart from paper “play money.” The fact that cryptocurrency, being complex software, can get stalled and much harder to pick up by someone else than currencies of simpler means.

20181206/https://www.ccn.com/research-over-1000-cryptocurrencies-are-dead-projects/

Time-keeping with Arduino and Raspberry Pi

quorten

2018-12-06

Categories: raspberry-pi  
Tags: raspberry-pi  

So, I’m wondering. What provisions does the Arduino have for time-keeping during runtime, and how does it compare with the Raspberry Pi? Oh, so this is interesting. The Arduino board has a crystal oscillator on it. So, that could function for it to get more accurate time-keeping than the Raspberry Pi, maybe.

So, how exactly does the Raspberry Pi do its time-keeping? What hardware does it use? Well, apparently it uses a built-in timer circuit on the SoC of some sort that is comparable to the timer circuit that other modern computers use to synchronize the operating system timer ticks. Also, modern operating systems don’t really continuously synchronize with the real-time clock (RTC) circuit, but rather generally only query it at boot time. So, suffice it to say, Raspberry Pi and Arduino are approximately equivalent in time-keeping functionality when properly calibrated. Maybe Arduino can do a little bit better at accurate time-keeping, but don’t expect anything particularly drastic.

20181206/https://en.wikipedia.org/wiki/Arduino
20181206/DuckDuckGo raspberry pi internal timer accuracy crystal oscillator
20181206/https://raspberrypi.stackexchange.com/questions/1397/how-accurate-is-raspberry-pis-timekeeping
20181206/https://raspberrypi.stackexchange.com/questions/7400/how-does-pi-keep-track-of-time-interval

TCP connection establishment

quorten

2018-12-06

Categories: random-software  
Tags: random-software  

Connection timed out? What, why am I seeing some network software getting an error of “connection timed out” during an accept()? Well, let’s quickly review how TCP connection establishment works. TCP uses a “three-way handshake” to establish a connection. Indeed, we are very familiar with the “connection timed out” error on the client-side during a connect() if the server fails to respond fast enough. But what about on the server-side? Well, because of the three-way handshake, it can also turn out that the client may fail to respond fast enough when the server send its response handshake back. Again, both sides can also be caused to get a “connection timed out” error due to the network dropping several packets.

The Wikipedia articles does a great job explaining the handshake process, along with some of the vulnerabilities of TCP.

20181206/https://en.wikipedia.org/wiki/Transmission_Control_Protocol#CONNECTION-ESTABLISHMENT

Wondering about all the “Connection reset by peer” errors you’re getting on your software? Well, well, this is easy to explain if you are getting those errors in an enterprise firewalled environment. That enterprise firewall is the cause of the “Connection reset by peer” errors, due to injecting and manipulating packets to cause that. In retrospect, this is a very rare error to receive “naturally” in modern computing environments because it is extremely rare for modern operating system hosts to crash.

20181206/https://en.wikipedia.org/wiki/TCP_reset_attack

Searching around for possible causes of “connection timed out,” I found this very interesting article. So, on a single system with communication via localhost, normally you wouldn’t expect packet loss in the communication. However, there is one exception. If the client or server fails to respond to a connection request within a time limit, then there will in effect be a loss of the handshake packets. Also, if the server is leaking sockets, this can also result in a curious situation where leaked sockets block the port that a server wants to open a socket on for accepting a connection. Client socket leaks don’t really happen due to a deliberate violation of the TCP specification to mitigate TCP SYN denial-of-service attacks. On the other hand, no such mitigation is implemented on the server-side, purportedly because server-side leaks are not seen as an attack vector. Yet, programming errors on the server-side can result in a similar leak and denial-of-service.

20181206/DuckDuckGo accept ETIMEDOUT
20181206/https://stackoverflow.com/questions/8471577/linux-tcp-connect-failure-with-etimedout
20181206/https://blog.cloudflare.com/this-is-strictly-a-violation-of-the-tcp-specification/
20181206/https://github.com/torvalds/linux/blob/c1e64e298b8cad309091b95d8436a0255c84f54a/net/socket.c#L1438

Updates on EOMA68 Earth Friendly Computing Device and RISC-V

quorten

2018-12-06

Categories: misc   raspberry-pi  
Tags: misc   raspberry-pi  

Are there any updates on EOMA Earth friendly computing devices? Yes!!! Now, this is quite the interesting update.

First of all, the PCBs have been printed.

20181205/https://www.crowdsupply.com/eoma68/micro-desktop/updates/what-do-1-000-eoma68-a20-pcbs-look-like

Second, in this past update, it has been pointed out that manual assembly of the PCB and the casework by the backers may be considered. The casework part, I’d be okay on that. The PCB? Well, you’re definitely right about it not being very hard, but needing to be done very carefully.

20181205/https://www.crowdsupply.com/eoma68/micro-desktop/updates/pcbs-and-components-have-been-ordered

Third, now this is very interesting. The Crowdsupply campaign for the RISC-V design is being put up with some initial updates. The actual campaign is not underway yet, but the development updates and status are being posted. And indeed, this is quite an ambitious project. Basic hardware accelerated 3D graphics rendering will be included, through the means of some RISC-V extensions and a Vulkan-based software graphics system called Kazan, written in Rust. Despite the complexity of such a proposal, it is actually made quite simple because of a variety of means. First of all, the architectural constraints of Vulkan effectively guide you toward creating a successful implementation. Second, some notable figures of the chip and 3D industry of times past are chipping in and providing guidance on this project, one of the benefits of it being done out in the open.

Indeed, some of the skepticism opinion is useful. It would be nice to see where the EOMA68 project lands when it’s finally complete. However, that seems to be doing pretty well, and if it does end on a relatively high note, I think we can say we have high hopes for this project doing better than we might expect at first glance.

20181205/https://www.crowdsupply.com/libre-risc-v/m-class
20181205/https://www.crowdsupply.com/libre-risc-v/m-class/updates/why-make-a-quad-core-64-bit-soc-surely-there-are-enough-already
20181205/https://www.crowdsupply.com/libre-risc-v/m-class/updates/comments-on-recent-phoronix-articles
20181205/https://www.phoronix.com/scan.php?page=news_item&px=Libre-GPU-RISC-V-Vulkan
20181205/https://www.phoronix.com/scan.php?page=news_item&px=Kazan-Vulkan-Rust
20181205/https://www.phoronix.com/scan.php?page=news_item&px=Quad-Core-Libre-SoC-Proposal

An interesting movie that portrayed 3D printing a person... sort of

quorten

2018-12-05

Categories: 3d-printing  
Tags: 3d-printing  

I happened to see a very interesting fragment of a larger show or movie. Some scientists discovered a fragment of a metal glove that they found DNA on. They then used that DNA to “3D print” a person. The show then had a very interesting following after the print process was complete. The person screamed and struggled at the very beginning, was confused as to why they were trapped inside a glass tube chamber, then the people in charge of the process came to her, showed her a badge, and started talking. (Alas, I saw this on a TV screen with no sound or closed captions.) After showing her the badge, she punched the sides of the glass tube broke through, and hit the person on the other side showing her the badge. The rest of the tube was opened up, and the medical staff came in with wrenches in hand of some sort. She then made a break for escaping the room.

On the other side after escaping, the police started chasing after her. They cornered her, and on their police visors, they tried to search for information on her. “Select category: Person or Animal. No file found.”

So, now this is very interesting. What was it that I saw? Well, I go a-searching, on the channel I saw SYFY in the corner, so surely that station name should have a website of a sort. And they do. It has a schedule…

20181205/https://www.syfy.com/schedule/

…but alas, they only allow you to see the future schedule.

Read on →

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