Take a look at the best screen recorders available for Linux. Learn its key features, pros, and cons.

Free and open source software for video recording and live streaming.

Download and start streaming quickly and easily on Windows, Mac or Linux.

You can download YouTube videos with VLC or even trim videos with it.

Another such unusual use of VLC is for screen recording.

I still recommend using a proper screen recorder for this task, you are welcome to explore this VLC feature for fun.

Screen recording with VLC
🚧
While I was able to use VLC for recording desktop screen, I could not record any sound and my mouse cursor. In my opinion, it's not a replacement of a proper screen recording tool.
To record your screen using VLC, open it and click on Media and select Convert/Save. (Or directly click on Media → Open Capture Device)

Select Convert/ Save option
Go to the "Capture Device" Tab and select Desktop from the Capture Mode dropdown list.

Douglas Proudfoot
5 hours ago
Part of any Russian decision to use nuclear weapons has to be an evaluation of how likely it is that the weapons will actually work as designed, and how Russian soldiers will react.

The reliability of Russian military equipment and ammunition in Ukraine has been spotty at best. At least 10% of conventional Russian missiles misfire or fall short. Firing the nuclear versions of these weapons is not an attractive option. They could detonate in Russia or on Russian held Ukrainian territory.

The dud rate is also a problem. If Putin uses a nuke, and it fails to detonate, Putin gets huge embarrassment. The corruption rampant in the Russian military makes this outcome possible, even probable. Nuclear weapons require careful component storage and maintenance. They’re fragile. The overall Russian record on Russian military storage and maintenance is really poor. The weapons have to be assembled and readied by technical people who know what they’re doing.

If the Ukrainians pick up a Russian dud nuke, nothing will stop them from rebuilding it and using it on Belgorod, Russia. Ukraine most certainly has the knowledge to do it.

Few of the Russian troops in Ukraine have been issued any protection equipment for nuclear, biological and chemical (NBC) weapons. Some barely have complete uniforms and are using bolt action rifles designed for World War I. Hardly any have been trained for NBC. They are in no condition to suvive the use of NBC on the battlefield. They would most likely flee in panic from any use of NBC.

My guess is that beyond the usual risk considerations of nuclear retaliation, Putin has to worry, a lot, about the reliability of his nuclear weapons and soldiers. Combining all these risks, in my opinion, increases the uncertainty to the point that no rational Russian Commander in Chief would order a nuclear attack on Ukraine. Even if Putin isn’t completely rational, his subordinates definitely are. They could react to an order to use nukes by overthrowing Putin. //

And, very importantly, the gloves would come off; no more restrictions by US/NATO on what Ukraine can target and the West would supply more and better.

And don't forget the China angle. There is NO way China permits Putin to do this. A tac nuke strike by Putin would leave him out to dry b/c China's not stupid; China would almost certainly decouple from Russia. No way China allows its Long Game to be affected by Putin's stupidity.

By Frank Hawkins

Young Bill Ayers
America has undergone enormous change during the nearly eight decades of my life. Today, America is a bitterly divided, poorly educated and morally fragile society with so-called mainstream politicians pushing cynical identity politics, socialism and open borders. The president of the United States is threatened with impeachment because the other side doesn’t like him. The once reasonably unbiased American media has evolved into a hysterical left wing mob. How could the stable and reasonably cohesive America of the 1950s have reached this point in just one lifetime? Who are the main culprits? Here’s my list of the 10 most destructive Americans of the last 80 years.

Ryan Maue
@RyanMaue
·
Follow
Wow. Guyana's president tells the climatists to shove it.
Anas Alhajji
@anasalhajji
A must watch!

This is my hero!

He is Mohamed Irfaan Ali, President of Guyana.

#Oil #Guyana
Embedded video https://twitter.com/RyanMaue/status/1773813984015127005
4:46 PM · Mar 29, 2024 //

BBC host Stephen Sackur essentially asked him during an interview isn't it a bad thing for you guys to extract $150 billion of oil and gas off your coast because of the carbon emissions that would ultimately be released into the atmosphere?

Ali's response is just pure gold. He stops Sackur cold and then just rips him a new one. //

First, Ali tells him they have a huge forest in Guyana that basically makes them carbon neutral because of how large it is, "a forest we have kept alive."

Sackur says, "Does that give you the right to release all of this carbon...."

Ali interrupts him, "Does that give you right to lecture us on climate change?"

"I will lecture YOU on climate change!" he said, pointing his finger at Sackur. Then he ripped him to pieces, using their own terms on him.

"Because we have kept this forest alive, that stores 90.5 gigatons of carbon. That you enjoy. That the world enjoys. That you don't pay us for...That you don't see a value in...Guess what? We have the lowest deforestation rate in the world." He said even with the greatest amount they could extract, they would still be "net zero." //

There was a little bit more that didn't make the above clip, where Ali explained the importance of paying for the development of the country.

Sackur complained that Greenpeace said the world needs to keep the majority of the world’s remaining fossil fuels in the ground.

But Ali was not having it.

“You just said that we are 6-feet below sea level. Who is going to pay for the infrastructure? Who is going to pay for the drainage and irrigation? Who is going to pay for the development and advancement of our country?” The President questioned. //

anon-pabn
a minute ago
That is perfect. We need to shame these climate alarmist, hypocrites. Set aside the current arguments, they are telling little Guyana not to drill after the rest of the world has drilled and prospered because of it. What balz! Drill, Baby, Drill. And congrats on your forest....better than any other countries efforts

James Madison is the Father of our Constitution, and the Robert H. Smith Center for the Constitution at Madison’s Montpelier provides educational programming for teachers, law enforcement officers, and others.

That seems appropriate. After all, not only did Madison—our country’s fourth president—help draft the Constitution, but he also served as a key delegate at the Constitutional Convention, authored the Bill of Rights, and urged ratification of the Constitution through his practical and philosophical arguments in The Federalist Papers.

But these accomplishments are, at best, downplayed at his historic home. Montpelier has no exhibits dedicated to Madison and his contributions.

Worse still, Montpelier is equipping educators to teach Marxist-based theories to elementary, middle, and high school students. And the programs doing this are, in part, funded by the state of Virginia. //

It’s sad that Montpelier has chosen to focus on a Marxist-motivated movement fueled by critical race theory, instead of on the many astounding achievements of the home’s former owner and the Father of our Constitution, James Madison.

It’s a disservice to the public, teachers, and students.

Scientists find a "mitotic stopwatch" that lets individual cells remember something. //

How does something as fundamental as a cell hold on to information across multiple divisions?

There's no one answer, and the details are really difficult to work out in many cases. But scientists have now worked out one memory system in detail. Cells are able to remember when their parent had a difficult time dividing—a problem that's often associated with DNA damage and cancer. And, if the problems are substantial enough, the two cells that result from a division will stop dividing themselves.

Supersonic flight without loud booms? NASA is working on that. //

When earlier designs flew faster than sound, individual shockwaves coming from different features like the nose, canopy, and wings merged into one powerful shockwave as they traveled to the ground. “We designed the X-59 so that those individual shockwaves don’t merge, which makes the boom quieter,” said Mike Buonanno, the X-59 air vehicle lead at Lockheed. //

“This way the vast majority of shocks generated by the X-59 are directed upward, and very few go to the ground,” Richardson explained. But perhaps the most unusual victim of eliminating shock-generating features was the canopy. The X-59 has no front-facing windows. //

And it is quiet—the sonic boom it will make should be around 75 PLdB, roughly like a car door slam from 20 feet away. //

On a New York to Paris flight, Concorde burned through roughly four times more fuel than the Boeing 747 while carrying one-fifth of the passengers.

The problem is that you can’t really do much about both fineness and lift-to-drag ratios—they're limitations imposed by pure physics. If you wanted to keep the right fineness ratio and have enough space for over 500 passengers in a supersonic airliner, you’d just need to make it absurdly long. //

Concorde used 119,600 L of fuel to carry 120 people 7200 km. That's 13.8 L/100km per passenger – almost exactly double the consumption of the Boeing 707, at best; it was worse on shorter flights. The subsonic planes that fly its routes now get 2.2 to 3.4 L/100km per passenger.

That, more than anything, is what killed it. Even if you sold every seat in a Concorde, it had six times the fuel bill per ticket of a similarly sized subsonic plane. It would have become uneconomical even if maintenance were negligible and spare parts were free, which they were not.

Can modern engine technology bring that down? Maybe. I can see 7 L/100km per passenger being potentially achievable with lots of R&D. //

RZetopan Ars Scholae Palatinae
8y
1,222
"At Mach 2.2, air friction heated up Concorde’s fuselage to 121° Celsius"

We see this error a lot, even when describing asteroids entering the atmosphere. The temperature rise is due to the rapid compression of air and not due to an alleged friction. A boundary layer forms near any surfaces parallel to the air flow (just like liquids flowing in a pipe) while the heat is generated at the leading and trailing edges where the surface is not parallel to the flow and the air must undergo a rapid change in speed. Any locations where the flow is forced to quickly change speed is where maximum heat is generated due to the rapid compression. These are the same locations where shock waves form in supersonic flows. Given the large number of errors in this article, we can assume that the author is neither familiar with fluid flows nor supersonic aircraft. Relying on mass market newspaper reports often leads to promoting totally nonsensical claims*.

*Having been subjected to newspaper reporters on multiple occasions, it is astonishing how wrong they can be, both before and after "informing" them. For a trivial example, look at what happened to Irving Finkel's report on a 4,000-year-old cuneiform translation: //

Wickwick Ars Legatus Legionis
14y
33,543
paulfdietz said:

I see your claim fairly often, and I find it very annoying. It seems to equate the heating in supersonic flow with the heating air undergoes in adiabatic compression, for example in a bicycle pump.

But heating at a shock is not an adiabatic (entropy conserving) process. Shocks are irreversible. Entropy increases across a shock as fast molecules slam into slow ones in a region a few mean free paths wide. Compression does occur at a shock, but the heating is higher than is required by the increase in density. Indeed, there is a finite upper limit to the density ratio of a gas going through a shock, regardless of Mach number.

At sufficiently high speed, and particularly for the atmospheric entry case you describe there, almost all the heating is due to dissipation. In that respect it's much more similar to friction (a dissipative process) than it is to adiabatic compression.

You're conflating isentropic (reversible) and adiabatic. Adiabatic is the correct term in this case. In the limit of mild shocks (or low-angle oblique shocks), a shock wave of pressure ratio -> approaches an isentropic process.

Almost all shocks are adiabatic. That just means there's no heat transfer during the process. Which is the case. My compressible flow book has a single chapter discussing non-adiabatic shocks at the end of the book. These are when water condenses out of air, e.g. There's no external heat transfer, but the gas phase loses energy to the liquid phase so it's a non-adiabatic process for the gas.

But that dissipation isn't friction. It's compression heating when the compression is done too fast.

Edit: Let's put some numbers on this. Let's consider a Mach 2.2 normal shock (at the tip of the nose) at 15 km. That's 12 kPa and, -56.5C (216.7K), and 195 mg/m^3 density.

My compressible flow tables put the pressure ratio at 5.48 and the temperature ratio at 1.8569 (for gamma = 1.4 or air). That means the density change is 2.95 (Pressure ratio over temp ratio). So we've got a final density of 575 mg/m^3 at 402.3K (129 C). Isentropic compression to achieve a density ratio of 2.95 would be a pressure ratio of 4.54 (again, gamma = 1.4). And the temperature ratio for an isentropic compression of pressure ratio 4.54 is 1.54. So the isentropic temperature rise (so no dissipation) would result in a temperature of 334K or 61 C. So the isentropic compression heating would be 117 deg. C while the adiabatic heating would be 185.6 deg. C. So, in fact, pure reversible heating would do more than half of the heating that is experienced through a normal shock wave at Mach 2.2.

Purdue University mathematics professor Clarence Waldo was only at the Indiana Statehouse to lobby for the school during budget talks in February of 1897. That’s when he happened to witness House Bill 246 – to legally change the value of the number pi to 3.2 – pass its third and final reading in the General Assembly’s lower house. //

Waldo resolved to make sure the Senate didn’t make the same embarrassing mistake, privately coaching several senators on how to speak against the bill. At the same time, newspapers outside the state were picking up the story, correctly making fun of Indiana legislators for being so easily hoodwinked.

Sen. Orrin Hubbel of Elkhart County took the lead in trying to kill the bill when it reached the floor of the Senate, calling it “utter folly” and stating he and his colleagues “might as well try to legislate water to run up hill as to establish mathematical truth by law,” according to a report in the Indianapolis Journal. 

Thankfully, the bill died before coming to a vote, but that was due more to Waldo’s lobbying and the negative publicity than any principled opposition based on basic mathematical knowledge. 

Malicious code planted in xz Utils has been circulating for more than a month. //

GolbatsEverywhere
This might have been the worst Linux backdoor in history except that it was caught so soon. An SSH authentication backdoor is surely worse than the Debian weak keys incident and also worse than Heartbleed, the two most notorious Linux security incidents that I can think of. Probably this would have been abused to hack most if not all of the Fortune 500, except Mr. Freund decided to investigate some small performance issue that anybody else would have dismissed as unimportant. We are spared only due to sheer dumb luck. This guy has probably just averted at least billions of dollars worth of damages. Cannot emphasize enough how grateful we should be to him right now. //

dwrd Ars Tribunus Militum
6y
2,020
Subscriptor++
Big oof, after reading the commit messages, I'm going to have to assume they owed some bad people a lot of money, or they had an involuntary sleepover at an undisclosed location with several ill-tempered fellows from the state secret police agency. //

This could have made it into a lot more places had they not been doing benchmarking at just the right time.
Milliseconds. About 500 milliseconds. That's what started him down the rabbit hole. He was bothered by a half-second hiccup in an ssh connection refusal. //

crepuscularbrolly Ars Scholae Palatinae
17y
802
Subscriptor++
Andres Freund's post on OpenWall indicates the backdoor is only injected if:
targeting only x86-64 linux
Building with gcc and the gnu linker
Running as part of a debian or RPM package build
But, better safe than sorry.

Third-party-Tools to check your configuration

The SBC6120 Model 2 is a conventional single board computer with the typical complement of EPROM, RAM, a RS232 serial port, an IDE disk interface, and an optional non-volatile RAM disk memory card. What makes it unique is that the CPU is the Harris HD-6120 PDP-8 on a chip. The 6120 is the second generation of single chip PDP-8 compatible microprocessors and was used in Digital's DECmate-I, II, III and III+ "personal" computers.

The SBC6120 can run all standard DEC paper tape software, such as FOCAL-69, with no changes. Simply use the ROM firmware on the SBC6120 to download FOCAL69.BIN from a PC connected to the console port (or use a real ASR-33 and read the real FOCAL-69 paper tape, if you’re so inclined!), start at 2008, and you’re running.

OS/278, OS/78 and, yes - OS/8 V3D or V3S - can all be booted on the SBC6120 using either RAM disk or IDE disk as mass storage devices. Since the console interface in the SBC6120 is KL8E compatible and does not use a HD-6121, there is no particular need to use OS/278 and real OS/8 V3D runs perfectly well.

The SBC6120 measures just 4.2 inches by 6.2 inches, or roughly the same size and shape as a standard 3½" disk drive. A four layer PC board with internal power planes was needed to fit all the parts in this space. A complete SBC6120 requires just 175mA at 5V to operate, and this requirement can easily be cut in half by omitting the LED POST code display. Imagine - you can have an entire PDP-8, running OS/8 from a RAM disk, that’s the size of a paperback book and runs on less than half a watt!

Celebrating the world's first minicomputer, and
the machine that taught me assembly language.

The 12-bit PDP-8 contained a single 12-bit accumulator (AC),
a 1-bit "Link" (L), and a 12-bit program counter (PC):

Original photo credit: Gerhard Kreuzer
Later models (the /e, /f, /m & /a) added a 12-bit multiplier quotient (MQ) register.

The term “minicomputer” was not coined to mean miniature, it
was originally meant to mean minimal, which is a term that,
more than anything else, accurately describes the PDP-8.

Whereas today's machines group their binary digits (bits) into sets of four in a system called “hexadecimal”, the PDP-8, like most computers of its era, used “octal” notation, grouping its bits into sets of three. This meant that the PDP-8's 12-bit words were written as four octal digits ranging from 0 through 7.

The first 3 bits of the machine's 12-bit word (its first octal digit) is the operation code (OpCode). This equipped the machine with just eight basic instructions:

CHECK DNS PROPAGATION
Whether you have recently changed your DNS records, switched web host, or started a new website - checking whether the DNS records are propagated globally is essential.

Check DNS, Urls + Redirects, Certificates and Content of your Website

Use this server to make DNS queries against an Unbound instance and get logs. The Unbound instance is configured very similarly to Let's Encrypt's production servers, and is started fresh for each query so there are no caching effects.

They're free, they're easy, they're open source, and they generate funny names. //

One is LocalSend, a cross-platform app with an open source client and protocol that I install wherever I can. The other lower-friction tool that's especially handy for guests and rarely used devices is SnapDrop, a website or web app you open on both devices and then send files through, entirely on your local network. It, too, has its code out there for anybody to view.

Neither of these apps is new, which is good. They've been around long enough to garner good reviews and trust from their users. Beyond sharing files between two humans, I've also leaned on them when setting up headless systems or other quirky devices. //

roo82
roo82 Ars Tribunus Militum
23y
2,137
Subscriptor++
I've been using PairDrop https://pairdrop.net/ instead of SnapDrop. It's a fork of SnapDrop with more features, and can also be self-hosted. That being said, I didn't know about LocalSend before this article, and might just switch to it instead.