Greetings and welcome to the Introduction to Astronomy. In this video, we are going to talk about a couple of things. We are going to talk about active galaxies, and specifically one type of active galaxy known as a quasar. So these are some very distant objects, and what represents some of the very earliest stages of things in the history of the universe. What were galaxies like long ago? Well, many of them were actually active galaxies or quasars, and have since settled down to the ordinary galaxies we see today. So let's go ahead and get started here. And what we see, what are the differences between a normal and an active galaxy? And there are two primary differences that we see. First of all, active galaxies are more luminous. They are putting out more energy. Luminous does not just mean brighter in terms of visible light, but can mean all sorts of things. Many times it can be x-ray, it can be radio emission. So they are not only putting out the visible light, but they are more luminous across the spectrum. And they emit what we call non-stellar radiation, or radiation, not radiation that is not produced by thermal activity of stars. So for most galaxies, an ordinary galaxy, its spectrum is essentially the combined spectrum of all of the stars that make it up. For active galaxies, its overall spectrum looks much different. And then we also use the term AGN, or active galactic nuclei, to talk about the activity in the nucleus of the galaxy, which in most cases is where something is going on, down in the nucleus of the galaxy, near the center, near that supermassive black hole, that is what is causing a galaxy to become active. So let's look at some examples of types of active galaxies. So one example of an active galaxy would be what we call a seaford galaxy. These are essentially spiral galaxies with an unusually bright nucleus. So what we see here for the nucleus is a lot brighter than we would normally expect for a typical spiral galaxy. That can often be also be associated with extensive bursts of star formation. So you can have sometimes see intense regions of star formation around as well. So seafords are one type that are associated with a spiral galaxy. Another would be what we call a radio galaxy. Now here we see the radio galaxy. They have, as you might expect, excess radio emission and often emit jets of material. So we see that here. The galaxy itself is down at the center. So this would be a nice, looks like a nice elliptical galaxy at the center. And it is emitting a lot more radio emission than a regular elliptical galaxy. And it has jets of material beaming out in each direction. You can see how highly collimated the beams are here as they leave this area. And then as they reach and strike the intergalactic medium, they then spread out into these great radio lobes. So this is actually a combined image looking at a couple of things in that you can see the optical emission, but you can also see the radio emission from the jets plowing in to material in between the galaxies. And when we look at the centers of these, the other thing that we'll see is that we call what we call a blazar. Now a blazar is actually the compact center of the galaxy. So when we see them, they are considered the central portion, so the very compact material going on at the center of, in this case, an elliptical galaxy. So what we're beginning to see is that certain types of galaxies, certain types of active galaxies are associated with certain type of normal galaxies. Seaford galaxies are an example of a spiral galaxy, whereas the blazars are related to the elliptical galaxies. Now the one we really want to look at here and take some time on is the quasars. So quasars are what we call a quasi-stellar radio source. And they are essentially a star-like object, meaning they look like a star, they just look like a point of light, but they are emitting radio waves. Now that's not unusual. Our sun does emit radio waves, but we can only detect them because we are so close. A nor-ordinary star, we would never be able to detect it. Even within our galaxy, we would not be able to detect it if emitting radio waves. So this was something very mysterious as to why these stars were emitting radio waves. And the other issue was that the spectral lines did not match with any that were known here on Earth. What were these things made up of? Their spectral lines did not match with what we saw here on the Earth. And in 1963, Martin Schmidt noted that the emission lines in the spectrum of a quasar known as 3C273 had the same spacing as the hydrogen lines. But they were extremely redshifted, not just slight redshifts, but an extreme redshift and in fact enough to show that it was receding at 15% the speed of light. So that is extremely fast, much faster than any star is moving, and much faster than the galaxies that had been used at the time, it's seen at the time, were moving. So if we use this, we now have, if we can use Hubble's law, which says that the velocity is equal or is related to Hubble's constant times the distance. That means this object must be extremely far away to be receding at such a great speed. So what are these quasars? Well, let's take a look here. And they are star-like, and we see here, it looks much like a star. A galaxy normally has some kind of extended structure to it. We see a couple examples of galaxies here. And they do not show the diffraction pattern, the cross-like pattern that we see that goes through the center of a star caused by the telescope that is observing it. So that is normally associated with a star. So if we'd look at this and would say, well, this is a star, it is a point source of light. But they are only star-like because they are so far away. This is actually the nucleus of a distant galaxy blazing incredibly bright. We now know of millions of these. Every single one of them shows a red shift. And they now have velocities going up to 96% the speed of light, meaning that these are things that existed very early in the history of our universe. Let's take a look at what this means in terms of Hubble's law. And what we see is that quasars are parts of galaxies. So since galaxies obey Hubble's law, so should the quasars. And that means that based on the measurements that we make, every single one of these is at least 10 billion light-years away. Our universe is 14 billion light-years, 14 billion years old. So these things are really the very first couple of billion years of the universe. There are none of them nearby. There are other types of active galaxies that we looked at, but nothing that matches what we see for a quasar. So whatever form these had to have only existed long ago, and this is a way to look at the early history of our universe. We are actually seeing, then, the early history of our universe. So here is an example when we take an image of one of these quasars and look in more closely. And if we blot out the quasar light, we can actually see that there is a galaxy around there as well, just much too faint to normally be seen. So there is actually a galaxy. This is the core of the galaxy. But if the core of the galaxy is receding at such a speed, then so will the entire galaxy. Now what we have to learn, we have to look at what is this energy source? What could be powering something to be this bright and be seen over such tremendous distances? And one thing to look at is how big this can possibly be. And what we look at is that an object cannot vary in brightness faster than it takes the time, the time it takes light to travel across it. If we look at an example, an object ten light years across would then, first we would see the increase in brightness from things on the near side. So if this is a cluster of stars or an object and looking at each of these different parts of this object, if it were this big, we would get the near side, we would get an increase in brightness. Then five years later, we would get an increase in brightness from the middle, and ten years later we would get the increase in brightness from the far side. So the increase in brightness instead of just jumping up really fast would take a much longer time to increase its brightness, because it takes time. Even if the whole thing got brighter at once, we would not know about it for ten years. Five years, we'd learn out the first side, five years later the next side, five years later the end. And then it would continue to vary in brightness. But quasars can vary with time periods of months or weeks. That means these things cannot be light years across, they cannot be galaxy size, they must be closer to solar system size. And what that means is what is the energy source of these quasars, what is the only thing that could possibly produce this much energy in such a small space. And that is where we're going to come back to the idea of a supermassive black hole being the energy source for a quasar. And quasars and active galaxies both have the same energy source, which is this supermassive black hole. What it is, is the black hole here at the center accretes material, so that accretion disk is where all the energy is coming from. So as material spirals around and into the black hole, it heats up to extremely high temperatures and gives off lots of energy. We can convert a good fraction of the mass into energy in something like this, before it actually spirals into the black hole. This is the only way we have to produce such a large amount of energy, lots of energy from a small amount of space. So we have lots of energy coming from a very small space. The only thing we know that will do that is this supermassive black hole. So let's finish up as we do with our summary and what we've looked at in this section. First of all, we saw that active galaxies differ from ordinary galaxies in two ways. They emit more energy, so more energy coming from them. And it's a different type of energy. It is non-stellar energy. It is sometimes called QSOs, our important type of active galaxies, and have been determined to be the core of very distant galaxies. The energy source of that active galaxy is a supermassive black hole at its center, which is being fed by material and therefore giving off a lot of energy. So that concludes this lecture on active galaxies and quasars. We'll be back again next time for another topic in astronomy. So until then, have a great day, everyone, and I will see you in class.


Good evening aspirants welcome to the hindi news analysis brought to you by Shankara Ice Academy today I'll be covering the hindi news edition dated 9th of December 2022 here I have displayed the news articles that will be analyzed in this discussion in today's discussion we'll be discussing about certain basic concepts we'll be discussing two important bills etc at the end I also have a quiz question for you so let's get to the discussion part now so first discussion is going to be based on this news article first of all I would like to request to our viewers to ignore the background noise as you know due to the cyclone there is continuous rain in Chennai so ignore the background noise now look at this news article it talks about a bill passed by Rajesh Sabha see as you know the winter session is going on in parliament so we'll be seeing many news related to bills regularly now on this list Rajesh Sabha has passed the wildlife protection amendment bill of 2022 this bill was already passed by Lok Sabha and now it awaits the ascent of president after that it will become an act you know the process now this news article reports that the bill has been passed and also certain concerns have been raised in this bill so in this backdrop we are going to learn about the new changes proposed by the bill to the wildlife protection act we'll also see one of the major concerns in the bill okay see as I said the wildlife protection amendment bill of 2022 aims to amend the wildlife protection act of 1972 now two reasons have been cited by the government behind the introduction of this new bill one is to increase the number of species protected under the law and second one is to implement the sites convention as you know sites stands for convention on international trade in endangered species India is parted to this convention so India is obligated to take appropriate measures for enforcing the provisions of this convention and through this amendment bill this purpose will be fulfilled let us come to the main part of this discussion which is the prominent provisions in the new bill see one of the major changes introduced by the bill is the changes to the schedules currently as you know WPA 1972 that is wildlife protection act of 1972 has six schedules these schedules are for specially protected plants specially protected animals and these schedules also list the vermin species what are vermin's they are the wild animals that are believed to be harmful to crops farm animals and which carry disease so currently we have six schedules but the new bill reduces the total number of schedules to four how this is done is earlier there were four schedules relating to the specially protected animals but now this is reduced to two so overall the number of schedules is reduced and secondly what you have to notice there is another change with respect to schedules the new bill aims to remove the schedule for the vermin species and in its place a new schedule has been inserted by this bill and this new schedule is for specimens listed in the appendices under sites okay that is appendix one two and three and whatever is listed under the schedule will be called scheduled specimens now I also said that there is a schedule for the protection of plant species but there is no change made by this bill to this schedule okay so the first change is with respect to the schedules now let me come to the second major change it is related to the conservation reserves see as per the existing act section 36a and 36b deals with conservation reserves what are conservation reserves these are the areas that are adjacent to national parks and sanctuaries and also those areas which link one protected area with another so the main purpose of such conservation reserve is protecting the landscapes seascapes flora and fauna and their habitat and as per the existing act section 36a empowers the state government to declare a conservation reserve but the new bill extends this power to the central government also this is done by proposing an amendment to section 38 as you can see here the section empowers the central government to declare areas as sanctuaries or national parks but now next to national parks conservation reserve will also be added by this bill that means a power which was limited only to the state governments is extended to the central government in case of conservation reserves but what about community reserves see community reserve is any private or community land which is not within the national park sanctuary or a conservation reserve a community reserve is declared when a community or an individual has volunteered to conserve wildlife and its habitat so a community reserve is outside the national park sanctuary etc and as per the WPA 1972 the power to declare a community reserve lies within the domain of state governments only and even now this power is with the state governments only central government has no say in it because the bill does not make any amendments regarding this power so this was the second major amendment that is extending the power of declaring conservation reserves to the central government now what is the third one for the first time the new bill aims to introduce provisions regarding the invasive species see as per the bill invasive species are those species which satisfy two main criteria one is it is not native to India and second its introduction or spread may threaten or adversely impact wildlife or its habitat and such invasive alien species includes both animal species and plant species also so for the first time provisions regarding the invasive species will be introduced by the bill and the bill empowers the central government to regulate or prohibit the import trade possession or proliferation of such invasive alien species also according to the bill an officer will be appointed for this purpose by the central government and such officer will be authorized to cease as well as dispose the invasive species so these are the three new major amendments proposed by the bill now let me take up the most contentious provision in the bill it is the amendment made to section 43 of the wildlife protection act this section 43 regulates transfer of animals actually the section prohibits the sale of captive animals animal articles or trophy by the person who has its possession but at the same time when a person transfers or transports an animal animal article or a trophy but not for the purpose of sale it is to be reported to the chief wildlife warden or an authorized officer within 30 days time this means that already allows transfer of animals now what the amendment says it particularly permits the captive elephants to be transferred or transported and to be used for religious or any other purpose as you know elephants are a part of many cultural events of our country so this provision will facilitate it but then why it is criticized first reason is elephant is a schedule one animal and it enjoys high protection so the wildlife activists and animal experts are worried that such transfer and transportation allowed by the act will harm the animals more importantly as I said such transferred and transported elephants can be used for religious or any other purpose here the term any other purpose is the problem because it seems to have limitless meaning the activists fear that this would potentially increase the demand for illegal capture of wild elephants and after they capture they will be cruelly trained in crawls what are crawls see here you can see an elephant in a crawl which is a small dark wooden enclosure so the provision will lead to illegal capture of wild animals they are cruel training and it will also allow commercial trade of live elephants and that is why the activists and environmentalists are concerned about this so that is all regarding the wildlife protection amendment bill of 2022 we saw four major amendments one was the changes made to the schedules there are six schedules now it will be reduced to four schedules and the second one we saw was there will be a schedule for listing the scheduled specimens and these specimens are the ones listed in appendices of sites and then there will be no schedule for vermin species now on and then central government now has the power to declare a conservation reserve and fourthly there are new provisions regarding invasive alien species and finally captive elephants can be transferred or transported for religious or any other purposes these are the major amendments which we discussed today I hope in the coming days we'll be discussing more contentious provisions in the bill now let me move on to the next news article discussion look at this article it says Tamil Nadu is going to become climate smart state do you know what is meant by climate smart that is what we're going to see in this discussion see before seeing what is meant by climate smart or climate smart cities and states we need to know the need for it as you know cities often lack the capacity to quickly develop measures that respond to climate change this situation leaves residents especially those who are at the bottom of these socioeconomic scale vulnerable to climate change's negative effects and this is where the climate smart cities become important these cities are those which are built with infrastructure conducive to resist the effects of climate change other than this these cities also have a mechanism of reducing its carbon footprint on the atmosphere so basically a climate smart city must have four features one is having a proper green cover second a good public transport system third sound waste management strategy and fourth such a city must be resilient to any natural calamity when a city is found to be good in all these parameters we call it as climate smart city okay so let me give you some of the climate smart cities around the world first let us take the case of Bogota and Johannesburg Bogota is in Colombia and Johannesburg is in South Africa these two cities have the best rapid transit bus lanes in the world so this ultimately motivates the people to use the public transport rather than the private transport second example we can take is Singapore Singapore has one of the best low-cost housings in the world but this scheme other than providing best housing facility to its citizens it also provides a climate resilient public housing it is said that these housing uses similar structures which helps in reducing the overall heat island effects that takes place in an urban area this is due to the fact that the rooftops are petal shapes and are properly ventilated which helps in reflecting back the solar radiation so while talking about climate smart cities how can we forget the Scandinavian cities because these cities promote the use of bicycles among its citizens and among all these cities Copenhagen is the perfect example of a bicycle friendly city so all these measures are taken as part of being a climate smart city i hope you understood what is it now it is said that Tamil Nadu is going to be a climate smart city now let me take up this ad which mentions steering Tamil Nadu to a climate smart state we just know so what is meant by being climate smart but leave that and look at this sidebar this bar provides some of the important information that is relevant for problems examination you can find the important environment related current affairs in this bar yes a new elephant reserve was announced in Tamil Nadu it is the Agastiyamalli then bird sanctuaries were announced one is the Kaluveli bird sanctuary and Anjarayan bird sanctuary and we also know that India's first slender lorus wildlife sanctuary was also declared in Tamil Nadu only it is situated in Kadavur and Tamil Nadu also has the first biodiversity heritage site of our country it is situated in Aritapatti and India's first Dugong conservation reserve is also situated in Tamil Nadu and a new wildlife sanctuary was announced it is the Kaveri south wildlife sanctuary and many sites were added to the list of ramsa convention have given the ramsa sites in Tamil Nadu here you can just go through it i just wanted you to know that all these sites are present in Tamil Nadu okay this will help you in problems so with these information let us move on to the next news article discussion so let us see what this next article says this news article talks about the Jallikattu case and now the news is that a constitution bench of supreme court has reserved its judgment regarding this issue i think you know that many petitions were filed in the supreme court seeking to strike down a Tamil Nadu law which protects Jallikattu so what is it why they want to ban it let us see all these in this discussion let me begin with some basic details about Jallikattu it is a traditional sport of Tamil Nadu that involves bulls it is basically a bull taming sport you can say it is similar to the Spanish bull fights and bull runs those who watch the Hindi film Zindagi Namilegi Dabara they know about the Spanish bull run am i right so this sport is also something similar to that Jallikattu traces its history to around 2000 years ago it dates back to 400 to 100 bc this sport is seen as an event to honor the bull owners who rear the bulls for mating also in those days it was conducted to select the most suitable bridegroom because this sport involves taming the bulls so those who tame the bulls are considered suitable to marry and most particularly this traditional sport of Tamil Nadu is associated with a Tamil festival Pongal it is conducted on the third day of Pongal it is called as Marta Pongal so what happens in this sport for this you need to know what this term Jallikattu means it has two terms Jalli and Kattu Jalli means silver and gold coins and Kattu means tide so what happens is a bull is let loose among a crowd of people so whoever tames it will get the coins which is tied to its horn so the people who participate in the sport try to hold on to the animals hump to stop it and sometimes they even run along with the bull if they can tame the bull and get the coins they win but if the bull wins then the bull owner gets the price and sometimes in this festival the participants get hurt many even die see not all types of bull are used for this sport there are certain breeds that are suitable for example Pulikulam breed and Kangaim breeds are used for this sport there is one more point here see the bulls which win in the festival are in high demand in the market so they fetch the highest price and these are the bulls that are demanded for breeding also now since the festival or the sport involves bulls it was banned in the year 2014 but why it was banned suddenly after so many years it is because in a 2011 notification the central government added bulls to the list of animals whose training and exhibition was prohibited so considering this notification in the year 2014 supreme court banned this bull taming sport of Jallikattu supreme court also struck down the act which facilitated conducting of this sport it was the Tamil Nadu regulation of Jallikattu act of 2009 so this move of the supreme court created a huge uproar among the tamilians and there were many protests across the state so the governor of the state issued an ordinance that authorized the continuation of Jallikattu and after this the state government took another important step it passed the prevention of cruelty to animals Tamil Nadu amendment act of 2017 mainly this act exempted Jallikattu from the prevention of cruelty to animals act of 1960 so this enabled the continuation of the sport Jallikattu so these are the events that are related to the Jallikattu issue now let me tell you why some want this sport to be banned the first and foremost reason is the animals involved in this sport are ill treated for instance it is said that to agitate the bull the bulls are fed alcohol they're even poked with sharp objects and even chili powder is thrown on its face so such kind of cruelty is said to be done to agitate the bull so this is the first reason why activists especially organizations like PETA are demanding the ban of this sport the next reason is gambling see this sport involves a lot of money so it is said that it is going against the core objective of the sport which is bull embracing but there are also certain groups that support Jallikattu it is my duty to give you the opinions of both sides but it is up to you to decide in an examination whether you'll be supporting the sport or you'll be against it okay now let me tell you the arguments by the proponents of this sport they want the sport because they see Jallikattu as a chance for the farmers to flaunt their personal strength and the strength of the bulls and the love for the cattle and also to showcase how well they have looked after their cattle secondly it is also said that Jallikattu is a traditional way to find out the most potent bull to breed with their cows and also they say this helps the peasant community to preserve their pure breed native bulls so this ensures biodiversity and also acts as geographical indicator and fourth and most important reason given by the proponents is it is a tradition of the Tamilians and it establishes their identity of hard work self-sufficiency and power so they argue that it is a cultural heritage of the state of Tamil Nadu and therefore it is protected under article 29 clause one of the constitution article 29 deals with the protection of interests of minorities and as per clause one of this article the minorities have the right to conserve their culture now the fifth and final reason given is they say it also establishes a cordial man-animal relationship because the owner of the bull treats the bull as a member of the family so these are the arguments of the supporters of Jallikattu there is also another sport in our country called Kambala it is held in Karnataka this is an annual buffalo race and it is also banned the reason cited for its ban was the cruelty faced by the buffaloes during the race but again here also an ordinance was passed to conduct the race and even supreme court interfered and advised the farmers to go easy on the buffaloes and even advised the farmers to not use whiplash on the buffaloes and Kambala is also seen as a tradition of the state so in case of Kambala and also in case of Jallikattu they are seen as their tradition and a way of protecting their native breeds that is why a ban imposed on Jallikattu was seen as a ban on their tradition that is why it is taking a lot of time for the supreme court to decide on this issue because now it is also required to address the substantial questions related to the interpretation of constitution itself they have to decide whether it comes under the cultural heritage of the state under article 29 clause 1 or not now I have given the arguments of both sides this will help you to form a neutral opinion on this issue as an aspirant you should be able to do that so I hope my purpose is fulfilled here I have given you a comprehensive discussion on Jallikattu so with these informations in mind let us move on to the next news article discussion let us take up this news article now it says the Maulana as a national fellowship has been discontinued see this fellowship offered scholarship for students from the minority communities and this fellowship was launched as part of implementing the Sachar panel recommendations so are we going to see about the fellowship no we'll rather focus on the Sachar panel recommendations see this committee that is the Sachar committee was appointed by the then prime minister Manmohan Singh in the year 2005 it was headed by former chief justice of Delhi High Court Rajendra Sachar its main purpose was to look into these socio-economic conditions of Muslims in India so after looking at these conditions it prepared a report titled social economic and education status of Muslim community of India this report presented a major finding which was Muslims constitute 14 percentage of the Indian population at that time and they only comprise 2.5 percentage of the Indian bureaucracy so on a whole to improve the living conditions of Muslims in India the committee gave 76 recommendations these recommendations were based on how to remove hurdles that prevent Indian Muslims from fully participating in the economic life political life and social mainstream of Indian life to name some let me read out some of the recommendations the commission recommended to set up an equal opportunity commission to look into the grievances of deprived groups like minorities a bill was even passed to set up this commission but after that it was forgotten so as of now there is no equal opportunity commission i think i'm right then it also recommended to create a nomination procedure to increase the participation of minorities in public bodies more importantly it even suggested to work out mechanisms to link the mother sars with higher secondary school board it even suggested to recognize the degrees from these mother sars for eligibility in banking examination defense and civil examinations so like this many other suggestions were provided by this committee i have given here you can just go through it so overall the government actually accepted these 72 recommendations subsequently it even passed many policy decisions related to the education skill development for muslim youths in india but it is said that governments actions were mainly focused on improving the standard of education among Muslims in india and this fellowship which is all in the news was one of them so that is all about this achar committee you can use these points in your main sansa writing whenever you talk about the upliftment of minorities because this is one such important panel that was focused on the minorities so these points in mind now let us move on to the next discussion so shall we take up an editorial for discussion if you'd have seen today's newspaper you can say that it is full of election news only even the editorial page is filled with it so i have taken this editorial article that talks about far right ideology but why suddenly it is in news now suddenly it is in news because of germany see yesterday 25 people were arrested in germany in a nationwide crackdown these 25 people were accused of being part of extremist groups who are planning to overthrow the german state here the most surprising fact about this crackdown is these 25 people included a sitting judge a former commander of elite paratroopers and also a former police officer so many top officers of the country are said to be involved in extremist group and that is why they were arrested see the far right ideology is one of the major issues faced by many countries now therefore we need to know what is it and we'll also see the issues associated with it finally we'll conclude by saying what germany should do to address this problem before that note down the syllabus that is given here so let us begin with the big question of what is far right ideology it is an ideology characterized by anti-democratic opposition towards equality yes it is a ideology that is a combination of two factors one is the anti-democratic attitudes and the second one is protection of social hierarchies see here anti-democratic attitudes means they are opposed to the theories or policies of democracy so this is seen as the extreme aspect of far right ideology on the other hand defending these social hierarchies is seen as the right-wing aspect so because of these aspects the far right ideology is also referred to as extreme right or right-wing extremism let me simplify it more see in this particular ideology the national community is defined as ethnic and exclusionary that is only those who belong to their own race belong to the people of the nation this is what they think that means the right-wing extremists they believe that their people their nation and their so-called race is superior to others and they are prepared to enforce this view by using violence also so this is the right-wing aspect of this ideology or we can say the first aspect of this ideology thinking that their national community is ethnic and exclusionary the second aspect is extremism that is the ideology strives to overthrow the democratic system and wants to create a dictatorship because of these dominating elements we can say that the ideology is often associated with many other things like anti-semitism racism xenophobia exclusionary nationalism authoritarianism and even conspiracy theories here i think you know anti-semitism means the hostility or prejudice against Jewish people and xenophobia is the dislike or prejudice against people from other countries so from this explanation about far right ideology itself you would have found many issues with this ideology it mainly produces a set of enemies these enemies are seen as a threat against the survival of their nation their culture or their race but the question is those who are termed as enemies are they really the enemies no because they are the immigrants ethnic and religious minorities those who are against racism fascism and also the left-wing supporters are considered enemies by the right-wing extremist people so this shows the conservative nature of proponents of this ideology and due to this conservative nature they also exhibit widespread contempt for other communities like LGBTQ community feminists homeless people and even disabled persons another major issue with this ideology is they target a particular group of people see some of the most prevalent conspiracy theories on the extreme right identify Jews and Muslims as their key enemies so this has led to oppression political violence forced assimilation ethnic cleansing and even genocide against these particular group of people what is forced assimilation here it means forcing an ethnic community or religious minority group to adopt a particular language norms customs traditions etc etc of a larger community those who belong to dominant culture and this is done by the government itself this forced assimilation even includes the enforcement of a new language and legislation education literature and worshipping like what happened just before the Sri Lankan civil war ethnic cleansing we have heard it many times it refers to the systematic forced removal of ethnic groups racial and religious groups from a given area here the intent is to make a region ethnically homogeneous in nature so based on all this if we even say that the right-wing extremism is a politically motivated violent behavior then it is also not wrong it's because the ideology justifies violent behavior within our democratic system we have examples from history that shows far right politics can i name one it includes fascism Nazism etc yes Nazism it is a far right ideology and politics so no wonder why Germany is facing issues related to far right ideology right but do you know Germany is a parliamentary democracy now it is no more a nazi country then what is the issue the issue is there is rise of several far right networks in Germany and these far right networks are having influence over serving members and retired members of the security agencies and state branches of Germany so this has raised concerns for example we saw in the beginning that 25 members were arrested it is said that among these 25 members there were members of Reichsburger also see this Reichsburger is a label for several far right groups and individuals in Germany these groups reject the legitimacy of the modern german state and they favor german reich or the post-war german state so in english we call this group as reich citizens movement or the citizens of reich it is said that this group was planning to attack the bundestag and wanted to bring down the government through a coup bundestag is nothing but the german federal parliament so by attacking the parliament they wanted to bring down the government and after that they wanted to establish a new empire modeled around the pre first world war imperial state and as i said the 25 members who were arrested included top officials of the germany but it did not go as planned rather it backfired as a result of which 25 members were arrested what you need to focus is all these reflect one main thing germany has witnessed the coming together of anti-semitic extremists from various sectors of society for a longer time and these extremists are motivated by conspiracy theories and also a longing for a imperial era they're not worried about their group's actual strength and capacity but still they are prepared to use force to overthrow the democratic german state this is what is happening in germany so basically germany is facing two types of far right challenges one is posed by the extremist groups like reichsburger and the other is by the main streaming of far right politics that is the top officials of germany are involved in far right politics because of this only even last year the germany government partially disbanded its elite special forces unit called as commando special crafty it is said that this partial disbandment happened after witnessing extremism within the highest ranks of this unit so the far right politics have invaded crucial arms of the government now how germany should tackle this issue germany is infamous for its horrific nazi past it has strong laws in place to combat extremist threats but despite its precautions far right groups are still gaining momentum so according to the author of the editorial article germany should make sure that the state institutions are not infiltrated by extremists otherwise they will bring down the government from inside itself and as part of this germany should also continue to suppress far right networks like reichsburger after this it should tackle the far right ideology politically this is how it should go according to the author of this editorial do you have any other ideas about how germany should act now post your ideas in the comment section so in this discussion we saw about far right ideology what are the issues in it we saw how germany is facing issues due to far right extremism and we can say it is going to be a tough task considering germany's nazi past so with all these points in mind let us move on to the next news article discussion now this news article talks about another bill called as the energy conservation amendment bill see this bill was introduced yesterday in the rajeshapa so let us see some of the important provisions of this bill the bill aims to amend the energy conservation act of 2001 and it wants to promote energy efficiency and energy conservation how see the bill seeks to establish carbon markets it also wants to enhance the scope of energy conservation building code it also wants to amend penalty provisions in the act and finally it also seeks to increase the number of members in the governing council of the bureau of energy efficiency this was the overview now as i said it wants to establish carbon markets but what is this carbon market for that you need to know about carbon trading what happens in carbon trading is governments set an overall limit or cap on the amount of emissions that are allowed from significant sources of carbon that is there will be a limit on how much you can emit carbon here the sources of carbon would include the power industry automotive industry and even air travel what the government will do is it will issue permits up to the agreed limit and these limits are either given free or even auctioned to companies so here if a company controls its own carbon significantly then it can trade the excess permits on the carbon market for cash but if it does not limit its emissions then it may have to buy extra permits so here the carbon markets turn the emissions reductions and emissions removals into tradable assets here we can trade the carbon emission permits so what the bill says see the bill empowers the central government to specify a carbon credit trading system or scheme the entities which are registered under the scheme can obtain carbon credit certificates from the central government or any authorized agencies such entities are also entitled to trade these certificates but remember the carbon credit cannot be exported it could only be used domestically but this condition is only until India fulfills its promises that were made at COP 21 and COP 26 okay along with this the bill also forces in some way to use non-fossil sources of energy see under the energy conservation act of 2001 central government is already empowered to specify energy consumption standards now the bill has made some additions to this now the government may mandate the designated consumers to meet a minimum share of energy consumption from non-fossil sources additionally different consumption thresholds may be specified for different non-fossil sources and consumer categories but they may be mandated to meet this minimum share of energy consumption using non-fossil sources but what if the consumer fails to meet the obligation then they will be punished with the penalty of up to 10 lakh rupees okay that is why I said the bill forces in some way to use non-fossil sources of energy so overall through these provisions the bill promotes energy efficiency and energy conservation so in this discussion we saw some of the important provisions maybe in the coming days we'll see other important provisions from the bill with these points in mind let us move on to the next news article discussion so for our last discussion let me take up this text and context article it talks about remittances according to the article remittances to India is said to touch a record 100 billion dollars in the year 2022 in 2021 India just received 89.4 billion dollars as remittances this data is according to world bank's latest release called remittances brave global headwinds but do you know why remittances are important let us find out now for that we need to understand the meaning of remittance simply it denotes a sum of money sent by one party to another but the context which we are using is the money that is sent by someone who is working abroad to their family back home in India okay but does India need it yes it is because it helps in the growth of countries GDP see the remittances that is the money that is received by the families are spent mostly on gross domestic products in their home country only that is in India itself so this helps in the growth of countries GDP other than that there are also other needs for such remittances for example it fulfills the needs of the recipients that is the families it helps them during their toughest times for example it is said that during COVID-19 the remittances to India actually increased and these remittances also play a role in reducing poverty because the remittances reach the rural poor and using this money they improve their livelihoods increase their resilience and also achieve their goals but particularly if we take growth how does it happen using remittances see these remittances help in starting new small-scale businesses so it fosters entrepreneurship how it is done because these money replaces the credit constraints which normally we face they need not look for credits from other financial institutions rather they can simply rely on these remittances and also because remittances are money it helps in giving better education and for having better health the recipients can easily meet their health needs and education related expenses which in turn helps in the growth of the nation so I hope you understood how it helps in the growth so now let's come to the question of the largest sources of remittances to India obviously the Gulf Cooperation Council countries are at the top this includes UAE, Bahrain, Saudi Arabia, Oman, Qatar, Kuwait apart from them India also receives a considerable amount of remittances from USA and UK but can these remittances turn to be negative actually yes because if they get large amounts of remittances then it might discourage the beneficiaries from working that is why it is said that the extent of positive impact of remittances depends on the income level of the receiving country okay in this discussion we saw about the basics of remittances and why it is needed and how it helps in growth so with this news article discussion we are moving to the next session which is the practice questions discussion session let me take up this first question which of the following is or are the advantages of carbon markets first encourages less carbon intensive lifestyle second stimulates innovation third enables greenwashing see the carbon markets effectively encourage less carbon intensive lifestyle right because you can trade your carbon permits and obviously it stimulates innovation because more innovation will be done to bring in products or measures that will reduce emissions then what about greenwashing see greenwashing refers to a process in which companies falsely market their green credentials for example misrepresenting climate neutral products or services in the market so is this the advantage no it is the disadvantage of carbon markets so the correct answer to this question is option d1 and 2 only now the second question i have taken this from prelims 2022 paper with reference to indian laws about wildlife protection consider the following statements first statement wild animals are the sole property of the government see actually this question was asked in prelims because last year itself the amendment to wildlife protection act was introduced in loksaba so here upc rather than asking about the amendment it stuck with the static knowledge about wildlife protection act so is first statement right yes it is correct because according to the act every wild animal other than vermin which is hunted shall be the property of state government and if such animal is hunted in a sanctuary or national park then it will be a property of central government and even in a verdict given by bombay high court it was said that wild animals including tigers should be treated as government property for all purposes so statement one is correct and here if you look the question also asks us to choose the correct statements only you can eliminate options b and d now either 2 is right or 3 is right let me read out the second statement when a wild animal is declared protected such animal is entitled for equal protection whether it is found in protected areas or outside the statement is right because here the wild animal is declared protected not where it is present the act does not discriminate between animals found in protected areas and outside just mentions that this animal is protected so wherever it is in India it is protected that is why statement is correct so the correct answer is option a one and two let us also see third statement apprehension of a protected wild animal becoming a danger to human life is sufficient ground for its capture or killing see if a wild animal becomes danger to human life or is diseased or disabled beyond recovery then only it can be allowed to be captured or killed by the competent authority just mere apprehension or fear that a wild animal could endanger human life as mentioned in the statement is not a ground for capture or killing just because you are afraid of tiger you cannot say that it should be captured or killed but on the other hand if that tiger enters a human settlement and endangers human life then it can be captured okay now let me take the next question it is a pair based question on one side different committees are given on the other side the recommendations of these committees are given first pair is HOTA committee civil service reformation this pair is correct only PC HOTA headed the committee that was constituted in the year 2004 he was a former UPSC chairman and the committee headed by him recommended that the age for entrance to the higher civil services should be between 21 to 24 years and the relaxation should be provided to candidates belonging to OBC communities schedule tribe and schedule cast communities so first pair is right second pair MULLA committee jail reforms yesterday i think we saw about jail reforms in a discussion this statement is also correct it is related to prison reforms only this committee even identified the rights of prisoners pair 2 is also correct now let me take the third pair Balwanthrai Mehta committee center state relations this is incorrect because this committee gave recommendation regarding panchayatraj institutions it is not related to center state relations since one pair is incorrect you can eliminate option D and since two pairs are correct you can eliminate option A also now fourth pair Suresh Tendulkar committee methodology of poverty calculation yes this is correct Tendulkar committee is known for its recommendation regarding poverty estimation in India so three pairs are correct therefore the correct answer to this question is option C three pair only here i have given the quiz question for you go through the question we have discussed some of these sites in our past discussions already if you find the correct answer post it in the comment section now let's take the mains practice question for today both are simple questions but among them one is a question that was asked in mains 2020 try to answer these questions and post it in the comment section whenever we get time we'll review your answer so this brings us to the end of today's session if you like this video don't forget to like comment and share and also subscribe to our Shankar IS Academy youtube channel for getting regular updates regarding current affairs i'll meet you all next week thank you


Fylaughter of the Form. Committee WHY 2016. I apologise for the late start with traffic problems this morning. Can everyone make sure that mobile phones and other electronic devices are switched to silent or airplane mode? Item of the Agenda on the agenda is taking business in private. Can we agree to take items three-and-four in private? Yr agenda yw unrhyw lle siaradais mae'n dweud i unrhyw fel sefydig, Yn y peth yw Etd-E01496 yn y cychwyn bwyliaeth ein haf, ar y cyfnod Yn Dwiogl oilon, ond Yn Gwlu'r Cymru, yn y peth, iawn, rydyn nhung i ddweud i ddwylogiaeth yr ystod purebethau yng Nghymru, Bill never, and at the time that petition was not closed then the issue of the bedroom tax was still on going. As committee members know that that have been subsequently being resolved through the additional powers on discretionary housing payments. The committee has to decide now whether we are content to close the petition or we are content is that the view of committee members should be closed now. That is great. Thanks very much. With that, the public part is closed. We will now go into private session.


What's up guys, Mike the coder here today we're going to talk about is this a binary tree a problem on hacker rank. So the only thing you need to understand about binary tree is that basically we're writing a function and we need to return whether this function is this tree is a binary search tree or not. So what you need to understand about binary search trees that everything on the left side must be less than the current node and anything on the right side must be greater than the current node. So as you could see in this picture, which I will now go to here, this is not a tree. It's not a binary search tree. And the reason why is because this right side is not greater than three, right? So two is not greater than three. This six maybe be greater than three, but because two is not greater than three, it's not a tree. Also five should be less than three. This node on the left side of this three must be less than it. Okay, it cannot be greater. So that's why this is not a binary tree. And yeah. So yeah. So what you could do to solve this problem is you could try to check is the left side of your is a left node smaller than your current node. And is your right node greater than your current node, right? Because if they are both true, then you have to keep checking, right? Now is if your left node is greater than your current node. So if this is greater than or equal, then it's definitely not it, right? And if the right node of two, if it's less than or equal to the your current node, then it's definitely not it. So like, so like, what you need to check for is essentially check for is your left node greater than or equal to your current node, as your right node, less than or equal to your current node. And if that's the case, then it's not it's not a binary tree. Now there are some edge cases you need to check also, you need to check if this whole subtree, this has whole thing has to be smaller than your current node. So if this if any node in your left tree is greater than your current node, it's not a tree. So you also need to check if this whole subtree on this side, is it if it's less than your current node, right? If it's less than your current node, it's not a tree, right? All these values have to be greater, too sick, all the values on your right side must be greater than three. So right side must be greater, must be greater than three, left side must be smaller. This must be smaller than three. It must be smaller than three. So that's essentially that's essentially the gist of it. Left side must be smaller than the current node. Right side must be greater than the current node. If any of these are false, it's not a tree. So yeah, the only issue is that you have to check all the values here must be smaller than the current node, and all the values here must be greater than your current node. So that's a little difficult to do it recursively. I'll show you my code now. So hard to do it recursively. But if you were like regularly, yeah, okay. So first of all, let's actually check first. So first of all, we need to check is the left node that I created to help her functions called check left and check right. So the first one is check. First one, check BST of our function, what I'm going to do is I'm just going to return is the left check possible and is the right check possible, right? So left check is checking, are all my values in roots left less than the current roots data? Right. So all my values on the left side must be less than the current roots data must be less than this three. And that's what this check left is going to check. Is all the values on the left side of my route is it less than the roots data, the current roots data? And if it is, this is going to be true. Check right is going to check are all my values on the right side, this right side, are all these values greater than three, they have to be greater than three. So I'm going to return roots. I'm going to check right, pass in the right side of the tree and roots data. So all the values on the right side of tree must be greater than roots data. And I'm returning both of these and I'm adding them because they both have to be the case. They both have to be the case where the left side is smaller, all the values on the left side is smaller than the current root. And all the values on the right side must be greater than the current root. So that's why I have and then together. So now we're going to check, we're going to explain what check left does. And it's a little confusing, but bear with me. If you what we're doing in check left is we are going to recursively call this function. Okay. If I guess if when we reach a null pointer, which is going to reach the end of something, we're going to return true, because this is the base case. When we reach the end, if we keep going to the left, let's say I keep going to the left, I'm just going to keep going, keep going, keep going until I reach this one. And then I'm going to keep going again. And then I'm going to hit null. So this is going to be like, empty null. If I hit null, pointer, I just returned true, because that means that, hey, if all of it worked out in the end, yeah, I'm going to return true. Now, if any of the roots data, any of the data that I hit, like if any of the nodes that I hit along this way of reaching to the end. So if I hit any of these nodes, any nodes, either this node, this node, this node, I hit any of them, right? And there are any of them are greater than this data, greater than three, our roots data, then it's not possible, right? Because what we're doing is that we need to make sure all the nodes on the left side, all the nodes on the left side must be less than the roots data has to be less than three. So if any one of these that I hit is greater than three, if any of these I hit is greater than three, then it's not true. Right. So we got to return false. And any of the values that I hit, any of my roots data is greater than or equal to the data. I'm returning false. Now this is a little tricky. These calls are going to be a little tricky to understand, but bear with me. We need to check the first one is a recursive call. So I need to check is roots left? Check left, right? Is it roots left less than or equal to roots data? So this is what's what we're going to do is if this if this node is the case, right? This is not this node is not the case currently, but let's say it was less than it. Let's say this was like, I don't know, let's say this was like two, okay, let's say this was two, let's say like for sake of the argument, okay? What this is going to do is we're going to, if this is the case, right, this, this if statement where is never going to hit, right? Because we know two is less than three, right? It's two is not greater than three, two is less than three. So this statement never gets called, right? This statement if statement, so it doesn't return false. So what is it going to do? Check left. We're at check left, right? It's going to recursively call on the left side, making sure that the left side, this side is also less than three. So we're going to keep going down to the left side until we reach to the end node, checking make sure all the values on the left side, all the nodes down here are less than our current root of three must be less than, okay, that's what this if statement is. Now, what else do we need to do? We need to recursively call and check, check left roots, left data is less than the current data. So what this is do this is a little tricky to understand, but you got to bear with me. There are some cases where it would fail. But what we need to do is that not only are we checking is this node less than three, right? So this first check, check left to make sure that all the values on the left side is less than the current three, but we need to also check are all the values of this side less than our parent group, right? This side has to be less than the current parent root. If we have a tree like 657, right, and then this side is actually 10, the left side. This would return false, right, we need to check. Is this side also less than five, okay? Is this left side also less than five, because all the values on the left side has to be less than your current current root. Also on the left side, it always has to be less than it. So what this second recursive call is checking is is the roots left less than data, less than the current data. Okay, that's what it's checking for is my left side also less than this current data. And if it is, it's going to return true, if it's not, it's going to return false. This part is going to get even more tricky to understand. Like left roots, right, roots, right, Ada, okay, let's say roots, right here. This is five, and this is 10. Okay, this is not a binary tree. Why is that because this 10 is greater than six, right? Remember all the values on here has to be less than six. All the values have to be less than six. So if we have 10 here, it's not possible, okay, because this 10 is not less than six. This 10 has to be on the right side, right, because any value that's greater than the current root must be on the right side. So that's why what this is checking for this check left roots, right data is checking is this right side, smaller in our root, whatever I'm currently on this part. The left side is right side, is it smaller than the root? If it is overturn true, if it's not, it returns false. All right, this is a little, little hard to understand also check right, roots, right, roots, data. This is check. So essentially, check right is another function I wrote. It's the same thing, same exact same concept, except check right is going to make sure anything on the right side is smaller than or equal to your data. So on this right side, if it's smaller than your current data, they are on it's false, not possible, right? So check right is making sure that all your values on the right side greater than your current data, all the all greater than it. So on for under this part, this check rights statement, what we need to do is we need to make sure the check right of the right side is going to be larger than a roots data, because if it's not, then it's impossible, right? Check right, the roots right side is greater than has to be greater than your root current roots data. OK, so check right. Now we have check right, check right is exact same concept. What it's doing is if the roots null pointer, we return true. If it's the roots data is less than or equal to data, return false. Check right is going to make sure that. We have root roots, roots, right, roots data, check right, check data. It's going to make sure the right side of the right rights of roots, right side is going to be greater than the data. And then it's going to recursively call on the right side, making sure the right side of the new other is greater than its data, like the current data that we passed in, right? And it's also going to check recursively call on the right side is the left side of its data on the right side, greater than the data. So like if, if we're on, if we're on like seven, and this was like two, right, this is not possible, right? Because this seven's left, two has to be greater than six. Two must be greater than six. Anything, all the values here must be greater than six. So two cannot be possible, right? This two cannot be possible. It's impossible because this, this, this side must be greater than the current's root of six. All the values on the right side must be greater than six. So this two is not possible. So what this is checking is, is that check, right? Is the left side greater than the data? So is the root, the side on this date, this data, is this left side? All right, this left two is a greater than the current roots data. Okay. And that's why we've got to pass on the roots left, this left and the data of six. So that's what this check right is. Check left is just making sure the roots left side is less than the current roots data. So like they're checking is, is that, is this left side, let's say we have seven and this was like, I don't know, let's say this was 10. What, what this is checking is check left, we have to make sure sevens left must be greater than seven, less than seven, right? The left side of seven, this, this nodes left must be greater than seven. So this is not possible. Right. That's what we need to check on the left side, because where the sevens left also is a binary search stream, it's also has nodes and values in it that are smaller, anything that's smaller than the node current node is on the left. Okay. So that's what this is checking and check left, left, you know, and then we end them both and yeah, we just return. So that's a whole gist of, is this a binary search tree? Hope you guys enjoy this video. Right. Come subscribe. I got a head out and yeah, peace.


All right, I'm gonna go ahead and get started. So I just added this because we started talking about it during Kent's thing, and I figured it deserved a wider audience because I have to re-explain this problem like every couple years when somebody discovers it. So what happens with butterfs is we have this concept called subvolumes. The subvolume has its own unique inode space. The subvolume is what we can take a snapshot of. So the common use case is you have a subvolume for your home directory, so you can snapshot your home directories. You have a subvolume for the root file system, so you can snapshot the root file system. In Facebook we have subvolumes for the container images. So you can snapshot a container image and start a container right away from a clean image. So the problem here is that when you snapshot it, it's literally just a metadata block that points to an existing block and adds reference counts. So you have the same files, the same data, and the same inode numbers. So you stats, if I have a picture in my home directory and my snapshot and I stat both of those files, I get the same inode number for both of these files. This confuses applications, rsync is the main one that we were concerned with at the time. Chris came up with this relatively simple solution which was the way rsync or find or anybody else uses to determine whether or not they've wandered into a different file system is you change stdev and the stats. So we have an anonymous block device that we allocate for every subvolume and when you stat a file, we give you that anonymous devices, stdev for that file. This is a really easy way to solve this problem because now rsync goes, okay, these two files, although they have the same inodes, they're different because they're on a different file system. When in reality they're on the same file system. Now, Slava's asking if there's slides. There's no slides because I wasn't planning on talking about this here because it makes me very angry. Every time this comes up, people yell and complain about how terribly broken it is. Sure, it's not a great solution because there's no file system that does this. There's no file system that has the same inodes, inode numbers but an unique inode space per subvolume. Because in reality, what you have is you have a subvolume ID and an inode number and this is how we export things over NFS. The NFS file handle thing, the unique ID, is the object ID of the root that the inode belongs to and the inode number and this combination is in fact unique. So when you do the file handle thing and SplatterFS has its own file handle, like every file system does, you get the object ID and the inode number. This works really, really well. Ceph does this as well. Same inode number, same FS, cool. So anyway, this comes up every few years when somebody discovers it and thinks it's super broken and then tells me all the ways that it's easy to fix and realizes quickly after a lot of emails that it's not actually that easy to fix. The most recent one was, oh, I keep blanking on his name. He maintained, yeah, Neil Brown. Neil Brown discovered this. This is particularly problematic for NFS because NFS, if you export the file system, the directory that contains the subvolume and its snapshots, then you can have the same inode numbers for a bunch of different files, but NFS on the client loses the fact that these are in different subvolumes and so it can't change the STDEV on the client because it doesn't know it. By the time that it gets over to the client, the client has lost all knowledge that this is a ButterFS backed file system. And so there's a lot of things that he tried to do in order to fix this. And eventually, what I want to do, and like Bruce said, this would probably work for NFSD, is that instead of doing all the weird things which he was like XORing random bytes and then he was XORing the object ID of the root into the inode number, and this ends up really terrible because you can still end up with the same number, is I want to extend STATX to tell you the subvolume, like essentially the subvolume ID so that you can say STATA file, because the other problem that you have with this is that if you STATA file, you get a different STDEV and you would don't actually know if this STDEV is on the same file system as another file and another snapshot. And so this kind of is problematic in a different way. If you want to know if these two things exist on the same file system. So I want to extend STATX to say to include two pieces of information. One is a UID for the file system, saying this inode belongs to this FSID. We have the concept of FSIDs everywhere, we have it in block ID, we have it in all of these places. I want to extend STATX to encode the FSID of the containing file system. This way we can easily tell if two files are in a different subvolume that they're a part of the same file system. This is for user space. And then what I want to do is add another field to STATX and so this is where it's a little bit. We can do one of two things. We can add a U64 to include the object ID of the root. So this is unique and so like then NFS can say like, okay, I know that these things are unique and then they can do whatever it wants to do. So know that these two objects are unique. Alternatively, ButterFS has UUIDs for all the subvolumes. So if we wanted to say, keeping in the theme of having UUIDs, we have STATX have two new UUID fields. One is the FSID for the file system as a whole. And then secondly is the subvolume of UUID, which is again still unique to ButterFS. And then again NFS can do, because then NFS has all the information it needs to have about whether or not this object is unique or not. So that's what I want to do. Question, in what way is that different from Snapshot Team EXT4 on LV Thin, right? You still get Snapshots of the file system, different block devices that are dynamically allocated. In what way is it different? In what way is the use case? Is the user's story different? So I think it's that you still have the same problems with the EXT4 Snapshots, right? Because, yeah. Yeah, as far as I understand it, we have this problem. Anybody that has the Snapshotting is gonna have this problem. The only people that do Snapshotting that don't have this problem is LVM or anybody that does it at the block layer level, right? Because then it's a completely separate block device. But for file system-based Snapshotting, like we're all gonna have this problem. Sorry, Layton is saying something. Yeah, so Layton is saying that this means formalizing the concept of file system and subvolume, and that may be a good thing, but we need to consider other FSSs might not fit neatly into those concepts. So that's what I'm kind of wondering, is like I know all of the local file systems that I pay attention to have FSIDs, right? Like E64 has that, XFS, I'm sure has it. I don't know about any, so who? Oh, does FAT, I don't think FAT does it.  So, how was I saying that, asking if FAT does it? So like I guess that's a good point because like EFI, USB stick, plug in, and it's not gonna have a UUID to spit out. Does that matter for that case though? Like you just simply don't have a value for that, and I don't think that's okay, right? Right. You're asking about UUID, right? Not FSID. Well like FSID, I'm using them interchangeably, but like FSID is like the UUID for the entire file system and then like the- Because there's a different FSID that's something. Okay, let's let Todd. Yeah, I think some of the FAT file systems actually do have a 32 and maybe 64 bit FSID, it's just not a UUID like thing. Right. And so that has come up when people have proposed generic file system APIs for setting the UUID on a file system if you wanna change it because not all file systems have UUIDs that are a standard 128 bit UUID. I think one of the bigger questions though is when you say that two files are in the same file system but they're in different sub volumes, kind of begs the question of what does in the same file system mean, right? One definition is you're allowed to move the file using rename between two different directories in the same file system or you are allowed to create hard links between two directories that are in the same file system and I'm not sure does ButterFest sub volumes allow you to do that? So ButterFest sub volumes you can't rename and you can't hard link, you can rough link. Okay. Yeah, because I think that's one of the things we will want to be very clear when we say what does it even mean that two directories are in the same file system because some people might think that that means you can MV between them or hard link between them and I think you have a different definition of what it means for they're in the same file system and I'm not sure you've clearly articulated your definition of, you know, from a user space application why would they care that they are in the same file system, right? One reason is they wanna do hard links. There may be others. So for my use case I need to know if these two files are the same file system is mostly just from like a maintenance thing, like oh this file is in this file system and this file is in this file system and so I need to unmount this specific file system and once I do that then I'm good or whatever. Like different maintenance tasks where I can go okay these are in the same file system and this is the file system that I'm looking for. What got me super excited about the ref link example? I mean whether we allow hard links someday whatever that seems less important but the thing that just jumped out at me, right, is that although I'm working on Linux, the kernel, you know I'm in Azure, right, and the idea that you could have two exports and suddenly with this change, you know, a few weeks ago, right, we can now do a ref link in theory. Now that doesn't help with everybody, right, because at the moment we don't allow that in the server but it's sort of like jumped out at me though, I guess we should. We should ask our server guys to allow that. You already support a copy range between different file systems and that's enough for ButterFS to implement a ref link. You don't need to support the clone operation. Copy range will do it. And I think maybe Kristoff had an objection because we had already supported like you said, we had already supported the copy chunk and I don't remember who it was but a number of years ago we had an objection from somebody so we chose the strictest form which was the clone basically. Where a CP, like when you do a CP instead of using what Windows uses or what a Mac would use to do CP which is offloading the copy to the server, it would require doing a ref link. Well, that works now. For example, if I mount to Samba with the change that went in a few weeks ago, copies instant because CP does a ref link. Right, but Olga implemented the copy file range across mounts for NFS and that should work for ButterFS and for CFS as well. Yeah, exactly. So I mean, I found it really exciting, the whole thing but your point is valid though about how do you find out the FSID? I looked at the EXFAT code just a second ago and it looks like they manufacture the FSID from the block device. Right. So it's a nice hack and it's probably good enough, right? Yeah, so this is mostly just to give the user more information, right? So it doesn't have to be perfect. It's first and foremost it is give the user more perfect information because right now I can stat a file and I can't tell where it's mounted because it gives me the anonymous BDEV, it doesn't give me the BDEV of the actual mounted file system. So that's a problem, right? So if I have the FSID, I just look at the FSID and I know where I'm mounted. And then the other, the second big thing is exporting things across NFS or SIFs or whatever and suddenly you get the same item numbers that are for different files. And giving the NFS guys more information of this is an FSID, like a different FSID or different subvolume or whatever, then it lets them do what they need to do in order to make the things unique. Yeah, I remember it came up with something on the KSMB, the kernel SMB server thread. The whole issue of FS, it was maybe something on the email thread a few months ago about this. And I think they properly advertise it now but at the same time I don't think it's as important as the NFS example because these are, if you're exporting two shares that happen to be the same thing underneath. That's the thing, it only confuses find or our sync or whatever, like NFS handles it fine like you, because again it's using the file handle and the file handle is resolved to the unique object. It's purely like user space trips over this thing and doesn't know what to do. And NFS has the ability in the protocol to tag this extra information so that it can then on the clients represent, okay, these are two separate file systems. Don't, like they're gonna be, like they could have overlapping item numbers, don't treat them as the same thing. And so like I need to have a way, a standard way to let NFS be able to do what NFS does. I don't care what they do. So I just need to have a way for them to know how to do it and a way to tell user space, hey look, this file belongs to this file system and so you can then do all of the like, find where my file system is or what disc it is, magic. And also a better way to like articulate that this is on a different sub volume from another file. So I was wondering why LVM, cloning, whatever you call it, doesn't have this problem. Because doesn't that just copy the entire block device so you get the FSIE copied as well. Yeah, but you get the different block device. So like it, so when you mount the snapshot or whatever you get unique, it's the same thing that what Butterfus does now. You get a different ST Dev. Also will that be persistent across reboots? Yeah, it'll be persistent because it uses the actual ST Dev of the actual device. Whereas we're using an anonymous one that's just random. And the other thing that I was wondering is, is static is the right place to put this? Or do you want an extended StataFest effectively? And then we can add several UUIDs or FSInfo or whatever comes, is chosen for that. Because then you have a UUID for your snapshot or UUID for your base, your complete file system thing in a UUID for devices on. Yeah, so like I think that some of this stuff, like the global FSID thing can be in a StataFest or whatever. It's just that you possibly don't want to cart this out every time someone does a stat system cart. Right, but I do need a way to tell stats, like this is the file system that I'm on, right? Because like, or you need to be able to say like, this file belongs to this file, do that mapping back. Kind of like that stat is the only interface for that, right? I don't know what to do. Stats, yeah. I'm just still a little confused about the FSID. It seems the main issue will be, the main argument that will be leveraged against this is, it needs to be something that makes sense for all file systems. And even for ButterFS, maybe it's just a terminology that's confusing me. If you say FSID, that doesn't really reflect the sub volume concept, right? Sub volume is not a file system, not a file system ID. So I think it should be some generic UUID that file systems can fill in or not fill in and then not provide the FSID information. Well, so all file systems have a UUID. So when I say FSID, what I mean is the FSWide UUID. So we have UUIDs, X4 has UUIDs and as far as I know, XFS has UUIDs. Like the, when I say FSID, I mean the FSUUID and then ButterFS takes it the next step further and that every sub volume has its own UUID as well. So like you can, like... It still has an inherent double meaning, so to speak, because some file systems don't really use it as a file system UID. They extend it to a different concept, which in this case is a sub volume. So like, I mean, I can easily just say, you know, U64, right? Like I think that having the UUID exportable or you know, we can just get it from BlockID, it's don't need to actually export that. Like having the UUID for the file system, we can already get that through other means. We don't necessarily have to have that. It's the sub volume, it makes it easier for user space to map back to what they're on. But the real issue is like having a way to articulate that you're on a separate I-node space. One option that you have, either with stat X or maybe stat FS. So stat FS already returns a field called FSID, right? Sometimes it's a digest of the UUID. Oh yeah. Others file systems maybe like temp FS or it's just STDF usually, but there's an identified fire. Maybe you could go the root of instead of adding things to stat X, use the add flags to say add root or whatever and then just get the FSID of the root. Okay. That's an option. One more thing, I don't know if you guys know but a couple of years back I added the file system watch to FS notify. The ability to watch events on the old super block. So ButterFest is supported but not a sub volume because of the fact that the FSID of the object inside the snapshot is different from the root. I accepted it. So just to, you know, that's one more issue that is out there. People cannot watch a sub volume. Okay. That's good to know. I didn't know that. This gets better and better. Layton says there's no add or sub volume constant NFC4, you'll need to run it through IETF anyway. Yeah, Layton, isn't there, I thought there was some way for you to articulate like this is on a different file system. Like as Neil was saying that he was gonna have to do something awkward for NFS2 but NFS3 or 4 were gonna be fine. As long as you have this other unique identifier to say like, okay, this identifier plus I know number. Okay, and like I don't know how you guys wouldn't do it but like I know Neil was trying to like mess with the I know numbers but if we could just give you a unique identifier that says, okay, this is the root or whatever. I didn't understand why he couldn't just use our file handle because we encode this in the file handle already but I mean, I have the information to give you. Just how do you want me to give it to you? Yeah, exactly. So it seems like even if you have one solution for NFS and a different solution for locally mounted files where you modulate the block ID so that R-Sync does the right thing for a local file system. ButterFS access through the local file system. You're still gonna have the issue for R-Sync because R-Sync is only going to know about, well, R-Sync or other POSIX only programs that are only using ST-DEV and the I-Node for a file system that started out as ButterFS with multiple sub volumes exported via NFS and then R-Sync works on the NFS client. So it seems like we still need to somehow do a best effort attempt to unify the I-Node numbers that are seen by the NFS client, right? I mean, even if it's just use a hash function that 64 bits will be mostly unique or something, right? Cause I think it's great to talk about things that work for programs that know how to use Stadex but it seems like there still needs to be some sort of best effort for naive programs or R-Sync on REL7 that is not using the fancy latest interface. Yeah, so like the ST-DEV thing is never going away specifically for that case, right? So what I'm talking about is the future is, we inside Facebook want to more easily say this file belongs to this disk so we can do X things, right? Clean way to do that is to export the FSID. I don't know what NFS has as far as options of unifying, but I know that Neil was like doing the XOR and all this stuff and he was just getting crucified for it but there appeared to exist a way to give the client enough information to do it as long as we had yet another unique identifier. And I've got the unique identifier, it's just which one do you want and how do you want it?  Yeah, which like the DEVT thing is a very elegant solution for this, right? Like it just solves it, at least on the local stuff. It doesn't solve it for NFS, but also REL7 doesn't support ButterFS, so I don't have to think about them. But REL7 could support ButterFS as accessed over NFS, right? Access over NFS, yeah, that's true.  Don't export the local cell volume and the snapshot over the same volume, problem solved. However, that wasn't well received. Could you maybe, do we have the time? Probably have. Could you maybe summarize the solutions that have been proposed and knacked so far? So Neil tried a variety of different ways to send the root object ID across to do some hashing. So like XOR and stuff. One, he just like made up a random number to XOR with the, he like XORed the dev team with the I know number, all this stuff Kristoff got really upset about. One thing that Kristoff always comes out with is like you need to make these sub like VFS mounts, which doesn't make any sense. Like if you still have the same problem, so he always says this and it makes zero sense. Is he trying to say Unikify by mount ID, no? Yeah, so I guess that's kind of what he's wanting is like he wants us to have a VFS mount for every sub volume. That is a non starter because the VFS mount has to have a unique sub volume, a unique super block. Now that clearly can be changed. We are programmers here. We can relax that sort of thing. However, you're talking about like an order of magnitude more VFS mounts. We have thousands of sub volumes and you're talking about how to like mount all of these things up anytime you walk into them and walk out of them. That's, no. Even the threads, right? You need threads per file system, right? So every mount would generate their own threads, so which will be another nightmare to take care of. Yeah, but there was another solution proposed I believe around two years back. I believe Mark Fasche was working on it on views, but I don't know how far it went though. Oh, I remember that. So it was basically, it has the same concept of having super, not super blocks, but a lightweight super block called view, which would basically be added to each sub volume mount and would supply the dev or something. Yeah, I'd like that would be reasonable too. I don't, this, I'm just tired of talking about this. Like I think that my solution is we extend SATFS and SATX to give us more information and then we let everybody else deal with that. I think that's the cleanest solution because everything else is hacky. The dev team thing is gonna stay forever because people are still running REL4, but as far as like how we move forward, I think that we exporting the UID for the file system is really helpful and supporting the sub volume UID per file for us is also helpful. The information that you said that you wanted to export to SATX, it's already available to NFSD, to Kernel NFSD. So the UID is available and the root is available? It's not yet. So like it's what NFSD uses KSATX, which it's not in there. So like it has no way of knowing that. So this is why I'm talking about extending it. What do you mean? So NFSD currently uses KSATX, right? Or whatever to get this? Yeah, but it has the entry. Oh, that's yeah.  It's just you get us, you get like the same, I don't know. Yeah, you can't tell. Yep. It calls get at her for the FS. That's what Clayton said. So like if we like, we need to stuff it somewhere so that somebody knows something. I can put the, I can give you the, if we don't like the UID, I can give you the U64 object ID of the root. That's unique. Right. Like, well that's the thing is like other people, like user space has use for this information. I mean, if enough people ask for it once it's in KSAT. Yeah, that's true. All right. I think just the final point, I think the main, it sounds like the main issue here will be to summarize the solutions that have already been proposed and why they were rejected to build a solid base for why this solution should be accepted. Right. So the solutions that were suggested is Kristoff's VFS mount thing. I mean, just when you send a new patch. Oh, when I send a new thing. Yeah. Okay. Sounds good. No, Ted's got one last thing. Yeah. It seems like there's a LWN article from, I think it's August, 2021. The title is butterfess. I know number epic. Yeah. Which I think actually already summarized all of these different solutions. So it may be sufficient just to reference LWN article. Yeah. I forgot that you guys wrote that.  And that's, you know, we'll be here a while. Cool. So we're running over time and we've got a joint session with IO track. Oh, sorry, Steve. So, you know, from my perspective, this is useful because it could affect, you know, kernel server, maybe, and you know, it's a useful topic. But what jumps out at me is static, ecstat, statx. This isn't the only thing that's like a 10 out of 10, obvious that ought to be added. I think that your idea of adding is good, but there's got to be some synergy for a few other things. There are, I think, six flags that I could add that NTFS also supports that seem to make just as much sense and just as important, you know, is a file offline, right? I mean, your app needs to, yeah, I don't know, but it's what I'm getting at, is that I think this is a 10 out of 10 important topic. So maybe we can talk about it tomorrow or the day after because there are other flags that have a lot of value ahead and, you know, for BTRFS integrity checking. Okay. And maybe we can talk about it more, but I think that it would be a good thing to talk about whether there's at least two file systems that need this, whether there's at least two file systems that need integrity checking or offline or because statx is easy, right? We can just add flags. Yeah. All right, let's, yeah, I see Omar. We're coming. All right, guys, we're moving over to the IO track. People on the virtual, on the Zoom call, if you want to watch this next one, go click on the Zoom link for the IO track. That's where we'll be. Thanks, everybody.


Hi, I'm Freddie DeMarco for Blackstar Potential, and this lesson will be on recording through USB. So if you have a Blackstar amp that has USB connectivity, like the ID Series amplifiers do, you can actually download the software. It's called the Insider Software, so you can download from the website for free. And with that software, you can do all kinds of deep editing, file management, but what's really cool is you can do direct recording right into a software program. I'm going to show you how to do that. Okay, so now that you've downloaded the software, simply launch the software on your computer, and then hook up a USB cable from the amp to the computer, and then turn on the amp, and you'll notice that the amp will be initialized and it will perform any updates to the amplifier, you know, the software connects with it. So now I could turn knobs on the amp and it will reflect what's going on in the software. But what I'm really going to want to do is use the software, you know, keep the amp out of the way and it's very convenient just to adjust things. I could turn on and off the delay, adjust the phaser, adjust the reverb, choose different effects, what have you, and all this is accessible to be recorded. So essentially, I'm going to GarageBand, but the first thing you want to do is go to preferences and make sure that you have selected ID core amplifier. I'm making my output the built-in output, but you could also select the output to be going right through the amplifier. So it's real easy to hook up just a step or two process there and you're good to record. So I'm going to go ahead and hit record because I have a track armed and it recognizes it coming from the input from the, you know, the driver. And as I'm recording, so we could hear it, I'll make some adjustments inside the software. Arming record and playing. Now notice in the software, I'll make some moves, I'll turn on and off the effect. Put back the reverb, add the delay back. Make the delay time, I could tap tempo it a little slower, let's check the phaser. Okay, we'll look over here at GarageBand and listen to what we've done. So it's actually working, so it's that easy to record. So this would work really great with multi-track recording or just to record to a backing track to work on your phrasing. But regardless, the whole idea is that the ID amplifiers work really well with the PC's and with the Macintosh computers to get direct recording right into a DAW system. Thanks for joining me for this lesson on USB recording.


Welcome to All Hands Update. Here's what's happening around your Navy. Opportunities for advancement are sought after by sailors in all career fields. The Navy announced it is increasing re-enlistment opportunities for active-duty sailors in over-manned career fields in New Nav-Admin. You can now request to re-enlist into the same reserve full-time support occupation if it is balanced or open, even if outside your Seaway window. For more information on the application process, read the Nav-Admin. The Navy commissioned the newest Virginia-class submarine, USS Illinois, during a ceremony in Groton, Connecticut. The ship's sponsor, First Lady Michelle Obama, expressed how proud she was of the crew and their families and announced Illinois Sailor of the Year. This Ryan Mock's officers have selected him as this ship's Sailor of the Year. So congratulations to Ryan and to his family. You can read more about what's happening around your Navy at Navy.mil.