Good afternoon folks. Thank you so much for joining us, whether live or via recording. And today we're down to the nucleus of just the really old guy and the really young lady with very very different experience orientations perspectives that we're going to bounce off each other and you folks and that raises questions in your mind. Send them in. We'll be happy to address them respectfully as understandingly as we can. We welcome those. So Redine Keahi Olalo has a wonderful background and probably understands as much about the role and value of the Hawaiian culture here as anyone I know and how it has been and is being treated in different sectors. And we're going to talk about that a little bit today because we're in the holidays and we have thrown up in a history that has not just neglected and ignored it but misrepresented it painfully wrongly. Is that a fair statement, Redine? I think so. Yes. Okay so tell us a little bit about that. How has Hawaiian culture and Hawaiian people, how have they been disrespected, disarmed, disturbed? Thank you for having me on. I'm glad that we could be on today together. You know my background is in researching incarceration in Hawaii and I think when I think about the kinds of ways that Hawaiians and other minorities have been treated throughout history I tend to like to look at systems because I think a lot of times you can see certain elements in particular systems that can be transferred onto another system where you'll see the same patterns. You know for example I think what we're seeing what I see in the way that prisoners in Hawaii are going through is similar and overlaps with the situation of COVID in 2020 particularly in the way that we view certain populations also in the way that they are affected by certain situations like the pandemic and I was on a Zoom call last night with some really amazing people who were talking about the prison landscape and it's really interesting to me for example that you know for the last four decades we've incarcerated Hawaiians at a disproportionate rate and one of the things that we were talking about last night was I'm just proportionate. I'm just interrupting but it's pretty extreme. So generally Hawaiians are generally 20% of our population in Hawaii but 40% of the prison population and that statistic in and of itself also is misleading because it's a statistic that keeps being reported year after year after year and so for me there's two implications in there. First of all when you go into a prison you know that it's way more than 40% for Native Hawaiian or other Pacific Islander and second of all why is that particular um data piece acceptable it's almost as if it's publicly accepted as the norm you know I'm sorry I lost my train of thought but you know what you're doing now so if I'm understanding you correctly in truth Hawaiians are not twice as likely to be incarcerated as others they are far more than three or four times as likely most definitely and there is an effect that theoretically might be called indirect that isn't because it is so deep and so personal that it is direct and that is they know that yes when they go outside they know that even if they're just walking down the street at night they are many times more likely to be stopped questioned treated adversarily disrespectfully suspiciously by people with legal authority. Yeah and there was a study that came out in the 80s that said that the deeper Native Hawaiians go into the criminal justice system the more likely they will be have longer sentences the more likely they will be violated on parole or probation and then receive even more punitive sanctions and then that also extends out to Native Hawaiians are the most disproportionately houseless in Hawaii which is a tremendous tragedy particularly when you look at the history of the illegal overthrow and the way that Native Hawaiians were a thriving community prior to that so you know I think it's pretty egregious what what is happening today still with Native Hawaiians this pandemic has one of the things that I'm on different platforms and I hear a lot of people you know complaining about the tourist economy and the industry and nobody's social distancing and tourists are coming here and being belligerent to hotel staff workers and all these kinds of things but really the root is that this was not a tourist economy in Hawaii and and Hawaii has been sold over and over and over and this is the culminating result of doing that of selling aloha so let me ask is not that sale process part of that that process of selling Hawaii as a commercial product not a culture not something human not something to respect and understand yes absolutely isn't that part of or is it part of the intentional expansion of inequality to serve a few of select groups some elements of which are racial and ethnic as well as gender this is not an accident right no no how does it connect with social justice well I mean I I think the obvious at least for me is that when you look at the prison industrial complex I mean black and brown bodies are we commodify them and you know you talk about a few privileged groups it's really the stockholders like in core civic who are making that that company's making billions of dollars because they're not only building private prisons to warehouse people who are considered throwaways by certain privileged groups but they also create subsidiaries of the company and they this industrial complex just keeps just keeps feeding itself really so you know I mean I think a lot of it is the way that we perceive certain populations and those who have privilege and power it is very purposeful to denigrate certain populations I one of the things I'll say and I'll let you go ahead Chuck is you know there's there's this tendency for us across the United States and in Hawaii to want to recognize disparate treatment but I think we're we're beyond record recognizing and acknowledging and apologizing for these things I and I think we we are at a stage where we have to be beyond these one-off solutions where we're going to celebrate somebody who did the right thing no this week I keep saying systemic change is needed but I'm starting to think we need a system overhaul really it needs to be turned upside down is it not the case that that systemic overhaul of a system that has become increasingly inequality driven for the benefit of the few at the expense of many by categorization in the way that people are treated not just commodification as you say but commodification objectifies someone who would dehumanize them right it flattens out all of the things that make them a unique human being of value for all of us hmm that's not right but it's not just and so the example that you're giving in the incarceration public safety sector it reflects exactly what is happening out on the streets with the police abuse situation in the schools with the disparate treatment of those same marginalized minority groups and it is exactly the same groups in each of those sectors healthcare education housing environment climate energy mental health those same marginalized groups that are being underserved that are being victimized that are being dehumanized and disrespected yes they're all individuals with human value how do we get back to prioritizing that I know I mean you know honestly some days I have feel like I have you know hundreds of answers for that and other days it just is mind-boggling to me that in the 21st century as globally connected as we all are that there still exists this tendency to look at somebody as if they are not human you know to just kind of detach so greatly from humanity that people are willing to mistreat people so terribly I mean you know this whole year obviously with the pandemic but also with the politics and the election and everything else has been concerning and yet interesting in some ways because what what is most fascinating not in a positive way but most fascinating is the fact that you know generally about 50% of our of united states citizens still hold views of certain populations as if they are not worthy of being full citizens and the thing that I go back to is this is the roots and the foundation of how America was built and I don't think that we really resolved that or healed from it and unless unless we really address it at the core it's going to keep it's blowing up now but it's going to keep you know presenting itself yeah we have the elected and appointed leaders who are actually using the words civil war advocating violence advocating secession we have not seen that in many lifetimes yes and they are doing that with impunity yes they are hey and so as much as we may understand that diversity equity and inclusion are key elements to moving back toward equality and away from the inequality that enables and in fact encourages these kinds of inhumane anti-human behaviors there is a fourth word element that is even more important and that is empowerment because if you diversify and make more equitable and more inclusive your education systems and your health care systems and your employment systems and all that stuff and you get more of the marginalized oppressed groups in but they're not in the decision-making position yes so the missing piece is empowerment the DEI by itself without the other E is ineffective I mean I would and we saw the results of the fact that you know people are not empowered or have a certain degree of power and I mean power in the greatest sense where you have power to serve others you know not to abuse them but I mean we saw that during the pandemic who the essential workers were you know it was all a lot of dispossessed populations they weren't sitting in the CEO's office or you know they were on the ground and they were essential and they've been the ones getting sick and they've been the ones losing their jobs and losing their homes and you know my question is you know at how do we empower certain populations I think there's been many movements toward that and yes they need to continue but at the same time I I feel like we should be further ahead than we are see and that's a great question baby that's it's a brilliant insight because as I was watching Times Person of the Year programs and as much respect in aloha as I have for Joe Biden and Kamala Harris and I do to me ultimately the true person of the year this year and everywhere but especially this year is the essential worker we need to honor that we need respect that we need to treat them in the ways that they have long deserved and that's possible because what history has shown is the only times in which essential workers have moved the needle at all toward equal treatment is after disasters especially epidemics and pandemics not so much after financial disasters so you didn't see it after the 2008 cracks right you did see it after the Wall Street crash back just before FDR because he came in and he engineered that direction whether accidentally or on purpose the infrastructure building projects okay and all of the job corps and organizations and groups that were part of that essentially treated and honored essential workers as the key element and rewarded them for that and allowed them to make living wages to have employment stability and security to be able to have homes to be able to have their children have access to education to be able to have access to health care that was a revolutionary shift in the 1930s that happened because the one other element besides strong alliances of people of conscience character and courage you have to have charismatic leaders who exemplify those same three elements of conscience character and courage it will not happen without hope they almost had it with JFK RFK and MLK right but all three of them were assassinated you don't have to have conspiracy theories to understand that the loss of those three charismatic egalitarian leaders enabled the direction that has taken place in the 40 years since that time which is the direction toward inequality at the expense of the marginalized and oppressed it is exactly what you're talking about absolutely and the company that you cite which is probably the leading private incarceration company in the country maybe in the world was just the subject of PBS interviews last night and one of the company representatives acknowledged that people have been treated far worse than they deserve and is acceptable on the record this was and it was interesting because it was not the CEO speaking for the company this was a young female who was actually allowed to answer the questions I wonder if she could yeah and the PBS host who was interviewing not not one of the best I mean not a racial man but she she kind of plotted through it and it was wonderful to see this young woman acknowledge that whole classes of people have been treated far worse and more humanely than they deserve and not to be able to have answers to to show what has changed that will reverse this direction and when you combine those two things categorical mistreatment of marginalized people and the lack of responsible change which is theoretically our show thing it leads you one place which is the same place that George Floyd's death led us to the same place that the revelation that Trump and his administration intentionally sought to further the spread of COVID fought the CDC maligned the CDC weakened the CDC and its ability to fight the pandemic with effective control measures and instead adopted and flaunted exactly the opposite knowing and intending that it would cause more illnesses more deaths more long-term effects right and also more hatred I mean by politicizing the mask as a symbol of representing so many things it's caused great division you know one of my mentors and I the great one of my greatest teachers was Honani K. Trask when I was at the university and she used to always say the fight is over the ideology and you'll find that ideology in symbols and it's true you know when we as citizens start to fight with each other over whether to wear a mask or not wear a mask and you know many of you see a lot of what Foucault talked about that the masses will start to surveil the masses and you're seeing that and it's just such a disruption in society that not only takes away from humanity but it takes away from our ability to be so much better for each other for for the place for our nation very disturbing with the way that the administration has purposefully caused harm on its citizens and it is not just the extent of the harm it is which citizen that is a categorical intentional harm right background marginalized oppressed people and how many sister Millie was my lost to the class name okay so Hawaii is the ultimate no degrees of separation place right yes and so one of the things that they brought home in my late best friend ever in life Pete Thompson was one of the activists in the Hawaiian studies program while holy wikani that was one of Honani's teammates in that struggle in that effort right and maybe that struggle its tone and spirit need to revive need to come back to life because it's that struggles tone and spirit the fight not just against oppression right with the fight for measurable meaningful progress toward real equality in law it's equal access to equal justice mm-hmm putting a marginalized person giving them access to the legal system and problem representation or even public defender represented mm-hmm does not level the playing field no exactly what you have studied and talked about and explained to us has proven that if it did we would not have a huge percentage a disproportionate percent of black and brown people incarcerated mm-hmm because what does that mean it is I think the metaphor of exactly what they face in life they are controlled yes they are restricted and they are without the freedoms without the choices without the human dignity honor and respect that the others who take that from them intentionally for their own benefit inflict on them mm-hmm so mm-hmm I'm left with the same four words that arose after George Floyd's and Breonna Taylor's mm-hmm the many other killings and that is that has to stop it does and we know that those patterns only stop if they are replaced by other and better patterns mm-hmm equal access to equal justice in every single sector has to replace what leads to that treatment in incarceration in education in police enforcement in healthcare in employment yeah I think tremendous point Chuck about the need not to just fight against oppression but to fight for something better and I would just cite the resistance Kapu Aloha that we saw with Mauna Kei it was one of the best movements I've seen in a long time and they did not just fight against what was wrong but they used that time to build to build what they envision as a thriving society and and they succeeded they succeeded and out of it came many good things I mean we even have a new political party in the election system so I think there's something to be said about what are we fighting for it's easy to want to fight against and we need to keep that front but we need to start thinking about it in terms of what do we want to see and just start building it and I think you're right I think our takeaway from 2020 hey and our hope and vision for 2021 is those alliances of people of conscience to fight for equal access to equal justice in all sectors because that's what Mauna Kei really symbolizes yes Radine thank you thank you it's been wonderful with you for all you are and all you do oh thank you and for all those who helped take us in that good direction keep having difficult conversations and making good trouble see you in 2021


I said before the game we were short on manpower but we were long on guts and I damn sure right. Cattle you have to drive. Some cattle you have to leave. They're kind of like football players. Some of them you leave, some of them you drive. They say the harder we play the behinder we got. We'll just get after Miami tomorrow like this old opponent got after that spear. We'll have a heck of a good ball game. There's a hell of a character searching there for you. That made a man reach and get it. Every man get a man, every good man get two. Run over a bad truck but I feel real good. To build this winning attitude off the field the Oilers got together after practice for country music, card games and congeniality. Here friendships were formed between coaches and players, veterans and rookies that would make the tough road ahead travel easier. Some of the most valuable lessons learned in San Angelo went deeper than simple exes and olds. Out of doubt Bum's probably one of the finest coaches I've ever played for. He's probably one of the most honest people that you'd ever want to meet in your life. To get together with his ball players he likes to have fun but you know we're out in the field we're not out here that long and he expects us to work. We got a game let's get ourselves ready. He deals with players from an individual standpoint you know the game of football is a game with people and how he treats people. As individuals I think he's the strongest. No one guy builds anything. I don't build this team. Our assistant coaches and our offensive and defensive people they're the ones that do it.  Which is it takes fans it takes an owner like Bud Adams. The four teams left today playing football and we were one of the four and I'm not going to let one ball game run hell of a year. Not anybody in the world more proud of Houston and the Houston fans and the Houston all the football team than I am.


So I don't see anything. I hope you can see me and you can see the slides So Some some words up front. So why did I make this talk? How did it came to to be a talk? my day-to-day job is information security management and in that job, I always have to explain Security problems to people who decide what to do Like we have a security bug here. What should we do? We have vulnerability. What should we do? so This is not everything, but this is a very important part and In January we had Malta inspector and like everybody was oh god. We are going to die. I Mean, we are going to die, but just not now I tried to explain them What the problem was and if it was a problem and for whom it is a problem and I found it's Difficult to explain the actual problem without some background and so I decided to provide the background to people who are Normal people I'm sorry. You are probably not normal people by this definition Because most of you will have opened a computer in their lifetime or two even wrote a program or two, so This is more like people who manage IT Normal people not developers, but the talk is something for everybody Because it will chat some light on the the other side You know the people who look at you with blank stairs when you explain them What Meltdown inspector is? So I can skip over that slide Yes, I look better I Do it I've been doing that for my whole life and I still like that and the interesting you know position in IT for me is between Deciders and IT so what okay as it met on the specters problem If you have a problem We have to do something that doesn't work anymore. So first. What is the problem? Okay Processes that is not like business process, but operating system processes must be isolated from each other this is like a primary Idea behind operating systems So what does it mean? You don't want this app To read the data of that app You don't want this browser tab to read the data of that browser tab You don't want these VMs to read the data of those VMs. Okay, so this is a very fundamental view on how computers work Especially in the cloud environment Or you don't want process a to read data on process B and You see the black gap in the middle That's a security boundary You don't see it, but it's there and Meltdown inspector break down that barrier and this is a problem There's some good sides to meltdown inspector And I will come to those So the first good thing is or the bad thing that depends on your system if your security strategy Depends on this boundary Then you have a problem if it doesn't depend on this boundary, you're fine you know that this one here it has a operating system and maybe Processes running on it meltdown inspector is not a problem Because even if I would be able to execute meltdown inspector attacks on here Process isolation is not you know the primary goal of this thing The second good thing is You cannot directly execute meltdown inspector remotely you have to run code on the CPU unfortunately JavaScript is also code that runs on the CPU and So I will give you know What often is low coin the management summary so what is meltdown? Well the end result is programs can read memory. They should not be able to read It affects on modern CPUs. Yes, I know some CPUs are not affected, but you know Intel MD 86 they all affected what is the attack vector? it's out of order execution and Cash timing for exhortation What are the fixes I will maybe highlight them later on The important thing is the fixes need the processor or either to be redesigned Or the operating system to drop some crucial performance optimizations namely They Are effective doing syscalls and so they have Two bad consequences versus performance Okay, that's bad. What's even worse is the fixes in the memory management and memory memory management is inherently optimized code In operating systems, and it's very very difficult, you know to turn around that to grab it and put it inside out So how bad is meltdown it's bad Spectre Goes a bit. It's a family of attacks it has Programming can programs can read memory and not only from other programs, but also from the hypervisor if they run in the VM It also affects all CPUs it's The fixes are recompiling all the programs Which might be difficult For example here this nobody has source code for that we compiling is difficult and Updating an operating system or a system that is running like doing business work With a change that of 100% Probably, you know could be difficult The vector is speculative execution. I will Show you the differences in this talk So is this a good these two slides are they good management summaries any ideas? Okay, they are really really bad They're good for you because you know understand you understand most of the words, maybe even all words your memory management understands bad and very bad and What's even worse is you tell them you're going to die But you don't tell them how to prevent that or when What the actual problem for them is? so We're going to play a game the threat or meter The magic idea is you have systems on the left side the green ones that are Low-risk systems for meltdown inspector meaning that either process isolation is not a problem like not a security building block or Running untrusted code is already the worst case Because if you run untrusted code and it's the worst case then meltdown inspector. It can't get worse than worst case The red side high-risk systems systems that are inherently vulnerable And we're an attack is very likely and we have process isolation is important So let's play a game. Where would public cloud go? It's probably high risk. Yes because it's runs untrusted code by design database server Medium, I would even say low risk for two reasons You normally don't want untrusted code on your database server So that would be already the worst case and the protection of database servers Normally is quite good because they're buried behind like two firewalls and application server So male server. Yes, I know I don't have icons for male servers male servers are also low risk in my opinion because you know Dove cat post fakes are you know really really major software? They've been audited a lot of times So the chance that you have execution there is quite low and as I said If you had an execute remote code execution, it would be already the worst case I'm not talking about exchange here or other group versus systems They can be a different thing a laptop Laptops are really, you know bad. You have JavaScript That runs on it and lots of programs And what it's even worse laptops You have a company like 80% of all workers have laptops You have a lot of patch and you have a lot of laptops so you cannot you know Put someone next to the laptop and do that you have to to do that in automated fashion And if you do that in an automated fashion, it has to work You don't want to kill 80% of your workforce By you know disabling their computer Mobile phones just the same firewalls I said Nothing should happen there and if something happens, it's bad enough. So the interesting part Application servers any ideas? Yeah, medium medium is a good point. I put it in medium, but it's you know, it depends Because remote code execution also meets code that you download from the internet like libraries Anybody here is doing continuous deployment You might have a problem So not for the old versions because they are very difficult to to to exploit eggs especially the specter But the new ones are different beasts. So if I was you know an evil genius I would look for a library, you know small library that's At the bottom of the library food chain. So that's included everywhere and then I would go to the maintainer the one who you know publishes the the artifact to To Maven or note or whatever and would either give you like a handful of money Or show me a picture of a family. I don't know it depends on the type and Then I would publish publish something that you know, waits a few weeks a month or two until I get some spread and then I would take over some data centers because you know the cloud there They run a lot of code even if it's a private cloud like this one and If I would be able to attack that That would be devastating for a lot of companies The good news is the old spectrum meltdown are more or less patched So meltdown is easy to to exploit but mostly patched and in most systems Specter the old versions are very difficult to exploit But the new version that are coming Probably way easier to exploit and interest announced that the patch arrives in August. So there's you know opportunity for For someone wants to do that So if you wake up in the morning, you're responsible for like a lot of computers and someone tells you this So what would you do? I mean What? What is your patching strategy? I mean you're smart. You already, you know created your your clusters And then you would look like cluster like for each cluster The lowest cluster probably ignored Because you know patching Probably does more damage than it helps the high risk cluster public cloud I would patch the public clouds even if I had you know the risk of Instabilities instabilities whatever, you know what I mean But that also means that you need to know what are your IT systems? So big company small company. It doesn't matter just think the Which IT systems do we have at home and I guarantee that? You will miss at least two and no scale that up to like hundreds and thousands of systems workplace systems routers switches Probably not the microwave not yet, but That's from the management side a very Challenging thing to do So the good side for of Melton inspector was it got attention got management attention to a very high level But it was so bad Yeah, until yet so That was the first part like management summary so the people with the blank stairs when you talk to them this is the part where I tell you how How did that happen?  What what happened and so to make that imagine you're running a Burgershop this is your first your first burger shop And you said you sell pizza you sell burgers you sell coffee. That's it Customers come in it's a takeaway. They place the order and You prepare the order and they leave so today's grant opening and you have your one waiter aka CPU core and One customer is basically one CPU instruction The order that the customer has like a burger and a coffee Are the micro operations of the CPU instruction? So what are micro operations? Sysk Complex system instruction sets CPUs like Intel break down the complex Instructions into many small instructions and schedule these For example adding two numbers. There's a special hardware for that Reading memory into the processor. There's special hardware for that Until they break that down into you know small pieces micro operations So and you do the same, you know, you get the the burger and the coffee and Then you prepare what you do so And then the customer goes or in CPU speak the instruction retires Retiring instruction means it becomes effective in the real world. We will see there's a shadow economy inside the processor But first, you know very first day you want to play it safe played safe means You get the order And you schedule the micro operations So first you grow the burger Then you brew the coffee and then the customer start what is good I mean, it's easy even the robot can do it It's very very easy. What is bad? It's very slow. Why is it slow? You have a lot of resources. You have pizza oven. You have a burger grill. You have a coffee machine. You don't utilize them They just stand sit around there doing nothing so the next idea is You get the order you schedule your micro operations, but this time You do them in parallel, you know the burger and the coffee and then you retire Instruction or gives the customer his order This is way way better because you have, you know It's twice as fast as the other version Because you have a way a better resource utilization You can do even better you can you know take the order and Why the order is prepared? You take the next customer and This lucky customer needs the resource that that is free the pizza oven And so now you're running two instruction in parallel in this case This is really good because you know you can't get any faster than that because you're using all your resources There's no no more room for improvement The next improvement would be like a second oven or a bigger burger grill or whatever But what what is really really important? Order is important. So you have to make sure that the yellow First customer gets his order before the green customer So at McDonald's or Burger King. This is probably not that much of an issue but if you do Computers or is important? I can you Grab that chair and sit down But I shouldn't do it the other way you know first sit down and then try to get the chair that doesn't work orders important Okay, so first orders completed and then second order So even more room for improvement We have more burger grills or pizza ovens and a better coffee machine We're still talking about one CPU core. This is not multi core multi CPU. Whatever. This is one core but for example the pizza oven could be the ALU there, you know adding numbers as Said the CPU has to make sure that the apparent order of instruction Stays the same, but if you look at that with three instructions running a parallel and The red one the second one has to be finished before the green one the third one So let's look what happens Okay, the yellow coffee the red coffee The yellow burger the green pizza Okay, the green orders already done before the you know while the red order still in progress This is a problem This would be a problem if the world would see the micro operations, but fortunately the CPU takes care of this it reorders Them so that this is seen to the world in the world like in the outside the program sees yellow red green at Basically, this is this is the core problem. I will show you later why But this optimization on the left Breaks down when the yellow Coffee cup Is something you do and in the little burger you check if you are allowed to do that Then you do something before you check that you're allowed to do that I'll show you so Why did meltdown inspector happen so accident malice and competence whatever the denies they tell into you know do that Or it's just a very very very complex system with Equally complex side conditions so I Would say it's complex side effects Just to code good If it can be explained by by malice and by neglect it's probably not malice People do things Not because they evil most of the time They do it because it seems right and What incident the other processor Companies did was a very very complex system to get very very fast processors Okay, this is special Slides for him and don't show that to your the non-technical people. I don't think Just quick show of hands. How many of you how know how an operating system handles memory? Yeah, I would say a third Okay, so this is not the main You know point of the talk but it shows you how operating system had a memory because This is The way operating system can handle memory and meltdown inspector are both, you know, tied together As I said processes are isolated from each other and so is the memory of a process like a process is a running program and Like the blue one at the top Cannot access the memory of the green one at the bottom Each process I'm talking now about 64-bit operating systems namely Linux They have an address room virtual address room as it is called So they're different address rooms both started zero and both and at two to the 64 minus one and They are on normal Intel CPUs like 48 terabytes So a bit more than, you know, what you put inside your computer as RAM and These this memory it's a segmented first Into pages Like It's four kilobyte pages on 86 But they all support larger pages, but for the sake of argument just leave it at 4k and The memory space itself for each process is also segmented. There's a user space and there's a colonel space So the colonel is operating system It's it is allowed to do everything, you know, it runs basically the computer The process is not allowed to do anything everything as you know what the operating system is for and what the colonel does it maps its data structures its memory inside the process of process memory at specific locations Why does do that performance reasons? I won't go into detail So I said the process itself like the program word or Thunderbird Doesn't have the permission to read the colonel memory and kind of obvious The colonel is high privilege and doesn't want to share all its secrets with user space So we have now seen two error scenarios Like like B and C B is process are a excesses memory of process B and C is process a excesses the colonel memory in its own address room B is very interesting because I said each process has its own virtual address room a Process cannot even you know name an address in process B It's like missing a dimension You can use pointers to say I want the address one two three four But it's always in your own address room. You cannot say one two three four in a process B That's the basics so both protections are attacked by meltdown inspector Meltdown attacks the protection of the colonel memory Spectre, you know just breaks all Spectres even worse they could be D that is accessing memory of the hypervisor So I told you that meltdown allows to access other processes memory and Now I said you can only access colonel memory So how does that you know? fit together, okay Colorful These are the two processes and in the middle you have physical memory and You know the blinking one This is a mapping like the blue page is mapped somewhere in physical memory and You know we have other pages like this page. It's not mapped at all So if you would access memory that's located in this page The processor would fault it would and the operating system would probably terminate your process It's kind of obvious that this must be the case if you think of like 48 terabytes of memory per process You know you can't back all that was you know physical memory and then you have maybe your memory that's Paged out to disk and then you have the red memory. This is the corner memory and the corner memory is The same everywhere But the same physical pages at the same virtual addresses the problem now is The colonel maps all physical addresses inside this virtual address room So it's a bit nested. So we have a virtual address room part of it belongs to the colonel and the colonel itself says I Want to have access to all physical memory pages so I map them Inside colonel space So that basically means That each physical run page is Mapped at least twice once in the corner once in the user space Again, this is done for performance reasons but this also means if I can read colonel space I can read the whole physical memory and That means I can read all pages that are mapped and not paged out or just not mapped And this way I can you know read other processes memory Okay So how do you know that? Well, I read the documentation this is memory map of Linux was 64 bits and Four level page tables. I want to explain page tables right now You see here that the yellow yellow one This is the direct mapping of all physical memory and the blue one at the top. That's your user space again Now I will show you how You know meltdown works. I Will go into Detail for meltdown. I won't go so much into detail for Spectre Meltdown works in three steps first You read a secret from a forbidden address So what address probably something in the colonel space? Then you know you hide away that Because you do something that's forbidden and the CPU will make sure that this has never have been happened You know and then you have someone else who you know finds that secret I would be sad we have how do a stash away that I do that by side channel attack What is the side channel When I was like a little kid So and my mother went to like the opera or the cinema or whatever I was you know strictly forbidden to watch TV And a good kid You know just wouldn't watch TV Well, but you know it was me so I Did watch TV and my mother had it a very very effective side channel attack on that. I Heard you're coming and switched off the TV and ran into my bed and pretended to sleep And left open to such channels the TV was warm and the bed was cold. It should have been the other way around So this is not you know TVs are not to be designed to be hot They just happen to be hot when you use them and so here you have memory Like RAM physical RAM all data stored in RAM if you work with it That's a process and RAM is just very very very very very very very slow Compared to CPU You know fetching one byte from RAM Literally it takes as long as doing hundreds of things If the CPU already had that memory that that data so like on 100 nanoseconds to get data from RAM. That's you know, it's a good value. It's a few years old, but you know For the sake of argument so explain the picture there's an address and in the address that's a value and So I said it's very very slow So what did clever people do, you know do something that's faster faster is cash cash is Extremely fast and extremely expensive that explains why not all your memory is made out of cash How does it work? The processor reads something. It's not in the cash You get it from RAM. So 100 nanoseconds later. You have the data You put it in your cash And like 103 nanoseconds later you have the data. This is not an improvement. It's it's more complex and it's slower The idea is that you most likely will you know use the same data value multiple times Or data like near the data you read For example, you read an array like chunk of memory. So if you read the first bit of the chunk of memory you're very Properly are going to read the rest as well and the CPU Just grabs that memory and puts it into the into the cache so that the next calls are very very fast So the good thing here is This is really fast like three nanoseconds. So What What's the loophole that we use and in meltdown? This is a load instruction Basically read something for memory. It has two micro operations Check if the program is allowed to do that That's the first operation The second operation is get the data The irony is for both instructions the CPU has probably go and fetch data for memory So in the for the first one it needs to get the page tell the entry Which is the the information that manages the pages I showed you And which contains the permissions some user space allowed. Yes or no And the second one is just getting the data from memory as you Would you know wanted so like burger example? You order a burger and a coffee? The burger is ready. The cuffing machine is broken. And so the customer doesn't get a burger and he doesn't get a coffee Well, this is the case that you know one fails That check says you are not allowed to do that And then the customer should not get his burger or his coffee But this is not so so this is program written down Check read magic Okay, left side is the logical view on the right side is what happens if the value is in the cache and And the page table entry is And in memory that's not necessary Precondition but the value has to be in cash So the CPU sees sees getting the data and working with it It's the fastest route to go and if I find out later that I shouldn't have been doing that I you know rewrite history and you know bought the process or whatever and this is no problem Why because the CPU is very good at making making things unhappen So as in the burger example So unless you know the the blue one the magic does something that is not detected by the CPU What cannot be undone by the CPU? So in this case The burger takes the customer takes a burger and runs away That's that's not the design that that I didn't mind when I designed my burger workflow But that can happen. This is a an attack. So we have two actors One is the spy and one the one is a collector In they both run in the same process. So we have memory on the right side a secret value and Some memory blocks the secret value can have the values one two or three For the sake of argument. So the spy will read the secret It will mark a memory block That corresponds to the value of the secret like in this the secret is three and it marks the block it's a three and then The operating system or the processor will find out that it shouldn't have been able to read the secret and Will like terminate it? but The mark still remains and so what the collector does is, you know, it just looks until it finds the mark It's block three. So the secret is three as well. How does it work like? in in the real world the secrets in the cache the Blocks are not cash Spy and collector can access the blocks and neither can access the secret because that wouldn't make any sense to Launch the attack if you can just read the memory Okay, this is to The spy will read the secret Depending on the value of the secret so spy will access Slash mark one of the blocks by accessing one of the blocks that will be pulled into the cache automatically Now the CPU finds out okay bad idea kill that But the block is still in the cache That's the side channel So what the collector now does is you know, it excesses all the memory blocks and low and behold one block is much much Faster to excess than the other blocks and that's the mark And so the collector knows the secret was three It's important that the content of the blocks of the gray war blocks is not relevant it's just If they are in the cache or not, so that's how meltdown works. I Mean If we think about it, it's very very easy. It's it's not a difficult attack But you know the super scala processors Enable that kind of attack Intel introduced them with a Pentium like 90 90 something so Quick summary meltdown uses out-of-order execution of micro operate of operations and micro operations and Uses a side channel attack via the cache This allows the attacker to read all the memory the colon memory Which often includes all the memory of other processes But the important point is This does not include the memory of the hypervisor or other VMs Okay Still awake or sleeping Okay, at least one is awake Spectre is I will gloss over spectre because spectre is really spooky Spectre is an attacking process Can make a victim process do something Without the victim process knowing what it does So how does that work? Okay, basically the same fourth victim to the secret special way the secret get the secret I'm Just looking at the yellow one and from a very high-level perspective The yellow one works by manipulating the branch prediction of the CPU. So what is the branch prediction? and What is this speculative execution? Okay This is me There's also So what will probably happen? If the waiter sees me standing in the line, he will brew me a coffee. I Didn't say what maybe I just wanted the burger, but He blew me a coffee. Why did he do that?  Yes, I will wait and the other customs will wait also Coffee done. Okay. Thank you This is a very good method to optimize The problem is if I don't want a coffee The processor has to throw away that you know it's Work that it shouldn't have been done in the first place and that's the difference between meltdown inspector In meltdown the processor knows Like out of order execution which which code to execute inspector it speculates speculative execution So this is a very complicated program it has a counter and B does something that's maybe of business value and see deference the counter Dechecks the counter counter's greater than zero great go to be this and You know counter zero continue What they see you like at this point will probably have recognized this probably the loop is going to happen because last 50 times it happened So it's safe to say that it happened this time And as long as the CPU is your confident that it can undo anything like the B and C If it turns out that you know counter was Zero It's it's the optimization. Oh, it makes the processor run better And the interesting thing here is Where is How does the CPU remember That D always jumps So we have two to the you know 64 bytes of memory Calculate no no no no we cannot you know remember that for each memory location for each process You have to use heuristics like if the virtual memory address ends with zero five It's probably going to jump That's a heuristic. It's a heuristic that's you know used across all processes And it works well the actual heuristics are you know trade secrets and Probably much much You know more complex, but that's the idea But as I said the heuristics and the counters like does it jump or not does it loop or not? are shared across processes It means that if one process Say at the address uh five five five five five five Oh five five five zero five whatever You know loops all the time The branch prediction for that address will be loop check. Yes Another process that is you know Something else the kernel kernel the hypervisor that happens to use the same virtual address for a comparison for a loop instruction Will be influenced by the statistics for the attacking or from the attacking process Okay, it's like a bit Yeah Is that understandable Is it the problem is basically shared state between processes in the processor And as programmers know shared state is always a bad idea. Yes So and this is how how it works. Um, you prime the branch prediction Um, and then you make sure that the other process does something that it shouldn't do What could it do? for example In the kernel Like linux you have The enhanced Berkeley packet filter Which can run script code Like byte code in colon So if you put some Script code in your address space It's also snapped in the colon's address space So if you happen to know where the kernel has like a jump instruction and you can influence that to call the The the Berkeley packet filter interpreter to run the code you put into your process space You can attack the kernel. Okay This is really complicated, you know, and you have to know all the addresses Where the jump instructions are where the data has to go whatever it's really really difficult And this is why spectra in the in the first versions is not so much of a problem. Okay, this is basically the attack You should be able to read that it's the attacker controls x and The attacker uses every one To access arbitrary memory just ignore the if condition first so the attacker puts in x reads some Like any memory relative to the start of area one And the value let's call it secret that it reads it uses to um Put another block of memory inside the cache You might recognize that from melton. It's exactly exactly the same what spectra does is um, it prompts the branch prediction so that the cpu thinks that x is always smaller errors at one size And so the cpu speculatively executes that and i'm told to hurry up a lot and so i do that I'm sorry. I'm sorry, but i'm There's another one And this is the attack that's actually really working is The branch prediction can not only say Does the loop happen? Yes or no It can also remember where the loop or the jump goes and this is then the way to you know run something completely different So I will skip over that Yes Shut up Got it so What did we learn? We have a management part on like how to manage Something like metronus spectra and it's really difficult and yes, i will hurry up And we have a technical a technical part So for the first versions of melton spectra, uh, my suggestion was Okay, plate safe test the patches and then roll them out Because I deemed the patches to be high risk and lo and behold, they were high risk and but You know the problem is, you know The slides are old, you know like a week Who would have thought that they are new new new bugs they are not They should have been released like two days ago They will be released in two weeks um And the the bad thing is there's a spectra variant Announced that is way way more easy to exploit than the old one And just remember We have A lot of libraries that we put into our code and patching These libraries like for bugs or continuous deployment might not be the best strategy to handle this attack But just saying Just shout So We have a micro thank you. We have a microphone troll. So if you have a question for jens, thanks for the talk I'm sorry for cutting you short, but we wanted to get in a few questions any questions from the audience. Please hands up Yeah, upfront Is it stay seated? relax Thanks for the talk. Um, you didn't mention anything about performance issues. Um If I fixed meltdown and spectre, how would that um, yeah result in the performance? um I mentioned that at the beginning like I glossed over it So to fix meltdown inspector just talk about fixing meltdown. What would be the fix to fix meltdown? Well, don't map the kernel memory when the user space is running If you do that, um you would like Kill a lot of caching mechanisms like the tlb and the the cache for the kernel memory and That would make calls into the kernel Very expensive because they would basically run into an empty cache so the the point is The more you depend on the kernel like syscalls The more like the fix for meltdown will hit you The fix for spectre that the google device has Not so much performance impact um, but the numbers for meltdown are like between 5 and 30 percent, you know, that depends on the cpu the operating system, especially what you do Another question. Oh, excellent. Yeah, uh, thank you for the talk and I wanted to ask you you mentioned that, um All modern cpu's are affected. So what about the risk cpu's and When you follow the media, for example, i am amd cpu's Maybe are not as much affected as intel or Okay, first when I said all modern cpu's I just lied to you um The second question is I cannot really answer that because I honestly do not know but a lot of these attacks are for example, especially spectre Are attacking cpu internals So different cpu internals between different results with the attacks My guess is At least, you know the widespread server cpu's x86 are all affected Just it doesn't matter if they're from amd or from from intel but That's you know for Someone who's better at you know it than me So you told that uh, we know that in in meltdown addresses were in the cache and We can see if they are in the cache or not. So The only thing I don't understand is how we how do we get the data so we can See if the address is there or not But how we can can we see read the data but we are not allowed to read the data directly. Okay, um Keep it keep it short. Very short. Okay. These are you know three memory blocks Um, I I I want to tell you that you know number two Is well the number two is a secret So I would sit on that chair I would get up and you will feel cold warm cold. Okay number two so You infer from you know the protocol that we have devised. What is the hot chair? um What the secret number is So This only works if I could you know steal the secret secret number from the cpu Because of the out of order execution of you know first give me the value and then check if I was allowed to do that Was it clear Yeah, I'm sorry by by by ends appear afterwards and he will explain it once more. Uh, the slides are available on that Oh, yes, also first all slides Are a open source So if if you want to use them at your company after your university or whatever Do so, please I mean, it's a lot of work and just for me or no, please and the other one is Is something missing boring was it awesome? Of course it was awesome, but feedback helps You know what's worse than sitting in a boring talk Making the next audience sitting in the same boring talk so Please give feedback. I don't know if you have a feedback system here. If you don't have one the sources are on github and I just happened to have opened an issue called feedback So just comment there. Thank you Thank you once more ends. Thank you very much


Welcome to lecture number 10, which is the second lecture of capsule number 5. Today we are going to look at drag and what efforts are made to reduce drag. In the last class we did look at methods to handle wave drag, so our task today is to look at drag and its reduction. When we talk about drag we first have to pay respect to Sir George Kelly who is widely considered to be the father of aeronautics. This is a portrait of Sir George Kelly and this is the only available photograph, real photograph of Sir George Kelly taken when he was approximately 80 years old. So drag basically is a force that opposes the motion of the aircraft and it acts only when there is some relative motion between the aircraft and the ambient air. For delta v the relative velocity between the object and the fluid that is needed to create drag and if there is no relative velocity or if there is no relative motion between the solid and the fluid then there will be no drag. We are all familiar that when you have air flow or relative velocity you get a force and the force is basically the reaction acting on the body, a component of that which is parallel to the free stream direction is called as the drag and that is overcome in flight by providing the thrust force. So essentially we need to have thrust more than drag if you would like to have forward flight and for that we will look at a special presentation on power plant or engines after the mid semester. So the question that many people want to know is who was the first person to actually talk about drag or observe drag and none other than the father of aeronautics Sir George Kelly. In fact not only drag he was the first person to talk about the four forces and the proof of this is in a silver coin that was etched in 1799 on one side of the coin was a sketch of Sir George Kelly's glider concept on the back side was this nice diagram which shows the action of the forces on a flat plate. So this is the first historically recorded sketch of the four forces acting on any flying body and he was a scientist who also did lot of experiments. So many years before Wright brothers actually Sir George Kelly designed and fabricated this whirling arm apparatus which was used to calculate or look at the forces acting on the body. Here is a small video clip of this apparatus so he is trying this is a this is a movie So this is a precursor to the wind tunnels called as the rotary arm or whirling arm apparatus. Such systems were used also to calculate the forces acting on airships and other bodies. And many many years before Wright brothers actually Kelly was able to carry out a manned flight but for that he designed a special aircraft called as a boy carrier because the first ever pilot of a manned aircraft was actually a 10 year old boy and this glider was designed to just accommodate a 10 year old person. There is a very interesting 50 page document on history of invention of airplane and on Sir George Kelly I am going to upload that on the Moodle for self-learning that gives a detailed information about what all Sir George Kelly has done. This picture has come from that particular document but he knew that if I attain flight using children or small boys people will not take it seriously. So then he designed something called as a governable parachute that is the name given by him. So on your left you see a photograph of or the design or the drawing of that on your left you see a drawing of that particular aircraft in mechanics magazine and on the right we see a full scale replica which was built in approximately 1972-74 where the historical flight was re-enacted by a very brave pilot. So there is a very interesting story about who was the first pilot to fly. Sir George Kelly was 79 years old when he designed this particular aircraft and he had recently hired a driver. So he told his driver why do not you fly my glider. So the driver had to obey his master but he was literally scared. So there was a successful flight therefore the first person to fly on a manned aircraft unpowered but manned aircraft which is not a balloon or lighter than air was the coachman and just after the flight he resigned these are very classical words he says Sir I was hired to drive not to fly ok so he resigned his name is John Applebee he was the coachman. He was 21 years old when he did this particular experiment. So in history if you want to record the first human being other than that 10 year old child who flew on a glider which was heavier than air but unpowered was John Applebee. The first flight was about 153 meters and this is the location where it took place. So this flight was re-enacted as I said in 1972 and in 1974 there was a television series which was shot in which this particular this scene is taken from that particular video series. So here is a picture of the full scale replica of this aircraft which was flown by Direct Ego in 1972. Notice that the rudder is hand operated. Nowadays rudder is foot operated but in this particular glider and there is a cable you can see which is attached because it is a glider there is no power plant. So you launch it with the cable. So it was a very successful flight of course they did a slight design changes and what changes they did and why they did it is an interesting observation which you should read that paper which I am going to upload. So this is just a small video clip in jest do not take it seriously but I really liked it. So this small video clip sums up the contribution. So this is even 15 and they have not been invented. Okay so this is just for some fun okay let us look at components of brag break it down into small components. So this is a very interesting slide and a lot of time was spent in making this slide you will know why because you will see there are various components. So let us first look at subsonic flow basically drag consists of many components the first component is profile drag this is pressure drag okay also called as form drag because it depends on or it is driven basically by the shape of the body mostly the front area and the pressure drag name comes because it is caused due to creation of pressure on the upper and lower surfaces because of the shape of the body. Now if you you have to add to that something called as skin friction drag which is because of the flow of air on the body. So one is shape the other is the surface area together they are called as profile drag. So profile is pressure plus skin friction or form plus skin friction and skin friction as you know can be because of laminar because of turbulent or because of both laminar and turbulent. So this particular part of drag acts even on bodies which are not generating any lift. So you can call it as lift independent profile drag we also have some lift dependent profile drag which we will see later okay is it clear? So something that does not depend upon lift it is a function of shape or form that is why it is form drag or pressure drag and it is also because of the skin friction. So the profile drag which does not depend upon lift is also called as parasite drag then you generate lift there will be an additional profile drag because of lift okay and that component should be a small component at cruise. So the induced drag is only lift dependent if there is no lift there is no induced drag and it occurs because of the lift that is generated and the lift is generated because of the vorticity which is shed in the wake. This is the story of subsonic drag in supersonic flow or in transonic flow actually you can also have wave drag because of the shock waves and here again there are components there is a wave drag due to lift and there is a wave drag due to volume. So all these together you call these components as drag due to lift and on the other hand you have zero lift drag okay. So this is the story of drag this is the breakdown of drag. Let us first attack induced drag which is created because of lift and the reason why we have induced drag is because of the creation of these vortices. Induced drag is caused by wingtip vortices these are caused by the difference in air pressure below and above the wing as you will remember from the creation of lift video. At the tips of the wing the higher pressured air below the wing can go around the tip to satisfy its insatiable urge to get with the lower pressure air on top of it. This creates a circular motion of air at the tips of the wings clockwise on the left anti-clockwise on the right. The vortices that this action creates affects the air around it. At the root of the wing where vortex action is not felt too much air flow is like this. However at the wing tips where there is a lot of the whole vortex action thing going on air flow is altered to become like this. As you can see the air is forced upwards in front of the wing and then forced downwards behind it. This alteration of the air then means that the lift generated by the wing is slightly deflected backwards. This lift force going backwards now adds to the drag force and is the induced drag of the aircraft. This drag is caused by wing tip vortices. So essentially induced drag there are many ways of explaining it. One way of explaining it is because of the presence of the tip or away from the root you are going to get some upwash before the aircraft and downwash behind the aircraft. So in a way the air has been made to tilt so there will be a reaction. So the lift vector will be canted backward. So this is another explanation where the same thing is explained let us see how they explain it. At high angles of attack the high pressure air below the wing likes to swirl around the wing tip towards the low pressure air above the wing. A twisting vortex of the air forms behind the wing deflecting the air flow downwards. An inclined local air flow is created which is the average of relative air flow resulting in the lift vector tilting backwards and contributing to total drag. At high angles of attack same thing just the tilting back. Now this tilting back is occurring because of the effect of the presence of the body locally. This does not occur at the wing root where there is a junction. This occurs only at near or at the wing tips where there is no junction. So you have relative wind on an aircraft you have thrust there is a net reaction but then there is a backward component and that backward component is the induced drag. So the reason why we have induced drag is because of the vortices at the wing tip. Now in this case the vortices are made visible. But sometimes nature also tells us or shows us the vortices. So you can also do it in the wing tunnel. That is the side wash. Oh yeah. You can see the curling up and inward turning of the vortices at wing tip. So that is the down wash. That is the side wash. Oh yeah. That is the vortices. Okay and if you want to have a visual information. This is a very beautiful video which shows what happens. We have already seen one such video. Here is another one. This is natural flow visualization. But my question to you will be why did the aircraft not land? It is coming into land and then it is rejecting the takeoff. So what happened? Why is the aircraft not landing? Do you think the pilot brought the aircraft down just to show you the vortices? No, I think the pilot wanted to land. That is why the flaps are down. This is something I would like you to answer. Notice it is only on one wing. You can visualize the vertex only on one end of the wing. Only on the port wing or the left wing as the pilot sees it. So this is a question which remains unanswered in the class and therefore I expect the answer unmovable. Somehow people have become little bit lazy unmovable now. I asked a question in the last class. Nobody has answered it. I hope you will get the answer to this question. Let us derive the expression for induced drag. So induced drag is basically a function of the same forces or the same parameters. But here I have used v equivalent and rho 0. You know you can replace it with rho infinity and v true square also. So the induced drag coefficient Cdi is basically a function of square of the lift coefficient and the aspect ratio of the wing. And for level flight or when you generate lift Cl is equal to L upon half rho v square s. So therefore induced drag will be obtained as a function of L square and K. So what are the parameters that affect induced drag? First is the lift. So an aircraft like Airbus A380 which will have more lift than a Cessna 172 will have more induced drag. At the same speed. Similarly lift is far, far more. An aircraft which has got a very high aspect ratio will have a lower induced drag as compared to an aircraft with low aspect ratio. In other words for the same aircraft if you change the aspect ratio, if you increase the aspect ratio you will reduce the induced drag of the same aircraft. So how do you do this? How do you change the aspect ratio of the aircraft during flight? What can be done for example? Any suggestions? During flight I want to have a higher aspect ratio created. What would you do? No suggestions? We have one suggestion. Take a mic please. Do we have a mic here? So mention your name. There is a mic for you. Mention your name and then give your suggestion. Sir my name is Deepak. Yes Deepak. Sir can we use this swept back wings to move forward so that B can increase and so that aspect ratio can increase. This is one way. One way of doing it is to sweep the wing to lower sweeps from higher sweeps. So if you are flying at a high sweep back and if you want to reduce induced drag you can sweep the wing ahead. That is okay. That Deepak you are right. Somewhere there there was a hand raised. Take a mic. Sir my name is Omitesh. We can deploy the flaps so that the surface area will increase. The aspect ratio will increase in that way. So if you increase surface area, aspect ratio is span square by area. Area increase will be reduced. Aspect ratio will come down. So actually induced drag will increase. Increase it will not decrease. Anything else? If you increase the area of the wing by deflecting the flaps. I am assuming it is Fowler flaps so you are bringing it back. Aspect ratio will not increase it will decrease because it is in the denominator. Oh that is fine. I understand what you are saying. Usually the definition of S is the wing reference area which may not include that. But my question to you is what is your suggestion to increase aspect ratio during flight? Sir money company. Yes. Sir it is the wing area if we increase the angle of attack projected area will reduce. So once again we come back to his point of view. There is something called as wing reference area which will not change too much. So just by increasing angle of attack you will not be able to change the aspect ratio. So why are you looking only at S? See how did Deepak sort the problem by increasing B? Can you do something else to increase the span? So we are working on a project in which we are talking of span extension. So you have a wing which has a wing and a small wing inside. And when you want high aspect ratio you take out that wing. So with that you get a larger wing span. Obviously it is not very straight forward but when you take out the wing what are the problems? Because you are eating away the volume available for the fuel in the wing. Secondly you have to put actuators to create so much load. So there is a plus and a minus. So we have a PhD student working on the pluses and the minuses and using detailed design calculations we are trying to figure out what is the limit to which increasing in span is beneficial compared to the drawbacks. So it is possible to do it by using innovative techniques. You can have a folded wing like this in flight and opens up like this. So you can do things to increase the span. But it is not very easy, there are many pluses and minuses. The other point is wing area and the equivalent air speed and the air density. So let us look at the factors which affect the induced drag. So let us see, now this is not aspect ratio but induced drag. Induced drag is more than the aspect ratio. So if you change the angle of attack then the lift is going to increase, correct. So this is one way. The angle of attack change is actually going to affect the induced drag. The next parameter is air speed. So if you change the air speed, the CL will change because you need to maintain lift equal to weight still. So as the air speed increases, the CL will reduce and if CL reduces CL square by pi A E will come down. So that is one way of reducing the induced drag fly faster, okay. That is one solution.


Did you feel like you had your best stuff today? No. I think it was one of those days where I didn't really have much out there, so I was just trying to compete. I was just thinking of my way. Did it have anything to do with throwing the two winnings two days ago? I mean, did it have anything to do with it? No, I don't think so. I think it was one of those days. I trained in the offseason for days like this where it was high or something like that. So, no, I'm not gonna say excuses.  Were you happy with the location on that pitch to Altuve there? I'm not sure. I haven't seen a replay yet, so that's something that I'll look out here for you. Chad, you said when you got out there, you just didn't have it. Did you know that in the bullpen? Did you know when you were warming up on the mound? When were you aware that you just didn't have your best stuff? I think it's just the misses. I think I know when I'm missing certain locations that I'll probably just fight myself a little bit. No, I felt good physically. I just didn't execute pitches. I didn't get good counts. When I did come in the zone, they could get swings on it. So it's just not going to go all off the route. I'll try to make it just in case. And, Chad, how frustrating is that to happen when you guys had a chance to sweep this series in a building you guys have had a lot of bad luck in over the years and a chance to complete a five-in-one road trip?  Now, this kind of leaves a sour taste in our mouth for three days. Yeah, I mean, obviously not where we want to end it. One out of five runs into the ninth. We should win that game 99% of the time. They've switched together. We'll just reset and get ready for Thursday. Thank you, Chad. Hey, Chad, despite that sour taste, I was speaking to Boone and he was just mentioning how there are some positive takeaways that you guys have. I think you guys really answered that calling. Yeah, man, I think we're putting together a really good at bats here. I mean, I think yourself. So, yeah, credit to our offense for grinding out at bats, really making pitchers work. Yeah, I mean, it was frustrating that we did put up seven runs a day and we might come away with the win. So, yeah, it's very encouraging of how our hitters are swinging it right now. Chad, in that last, that bat against Altuve, I mean, I know he got you earlier this year back in the Bronx as well. What was going through your mind? How are you trying to approach him in that situation? And what makes him so tough? Yeah, man, I think going like that, I know he's going to try to be aggressive. So, I'm going to try to reset to my advantage. I'm going to try to be aggressive. I'm going to try to be aggressive. So, I'm going to try to reset to my advantage. And I was the kind of the thought process going through the last pitch and I was going to try to make a chase. And I mean, I haven't looked at the replay, but I would have seen that bowl was not a strike. It was going to be a strike. But yeah, he's a good hitter. He's gotten me a few times. So, yeah, you can definitely put a good swing on it. Chad, you guys are at the break eight back of Boston. I think there's five or six teams ahead of you in the wild card. You have Boston eight out of 10 coming out of the break.   I think we just got to try to take a day today, try to play your best baseball that day. Because if you look too much into the future and worry about moving ahead of you, who's behind you, I think it can be pretty exhausting. I think it's going to be a football part. Take it one day at a time and just go for that. That is a crucial stretch for you guys, right? Yeah, I mean, for sure. I think anytime you're playing whether it's Boston or Toronto or Tampa, I don't think it matters. Those are all going to be big games within their positions. So, yeah, I think we're very serious and try to play good baseball. Well, in listening to both Chad Green and Aaron Boone, the absence of our oldest chap and are not wanting to get him in those type situations. Absolutely as a correlation to this loss, because as Boone said, it became a safe situation after Hermann gave up a couple of hits. That would normally be a spot for Chapman. Yeah, there's a lot going on listening to both of the guys. And the one thing I want to say is Chad Green is at an amazing first half and probably should be going to the All-Star game. But to your point, when Chapman went down and he's not the closer anymore, and Chad Green has been pitching important innings all year, he pitched even more important innings. So the intensity level, the adrenaline, it takes a little more out of you. And he's not going to mention it that he's fatigued and he was tired. But there was no doubt in my mind that he didn't have a whole lot today, which he acknowledged. But relievers, when the phone rings in the bullpen and they get going in their mind, they're always saying, I'm going to find a way to get these outs. When I jog from the bullpen to that mound, I'll find a way to get it done. I think Aaron Boone needed to realize that he didn't have a whole lot. When he rallied in the middle of the inning, I didn't see that. I saw one good fastball that he located that had some life on it. Everything else would look like it was a struggle.