Uniform General Closing Instructions: Fill & Download for Free

There are different ways to look at this question, under the framework of general relativity.The first way is the standard explanation: the escape velocity just outside the event horizon of a black hole exceeds the velocity of light itself. But no real body may accelerate beyond the speed of light, as per special relativity, and hence, bodies that fall into the event horizon can never make it back once inside. This also means, interestingly, that near a black hole, motion in space becomes uni-directional (towards the centre of the black hole), just like our regular uni-directional “motion” in time which we perceive as the irreversible transition from order to disorder.The second way is somewhat similar, but it is more instructive when one desires to delve into the math of general relativity. The distribution of matter and energy, in space, distorts or “curves” the geometry of spacetime itself, as given by the contracted equation,[math]G_{\mu \nu}=\frac{8 \pi G}{c^4} T_{\mu \nu}[/math]The L.H.S. of the above equation is the so-called Einstein tensor, which tells us about the geometry or curvature of spacetime. And this is linearly affected by the term on the R.H.S., called the stress-energy-momentum tensor, which tells us about the distribution of matter and energy in a given region of spacetime (which leads to a “smoothening” of the exact configuration of matter and/or energy, making General Relativity a non-localized formulation of physical laws).Now, certain solutions to these equations (which are actually a set of 10 non-linear second-order partial differential equations) show that for a specific density of matter/energy in a body, the curvature of spacetime becomes such that geodesics in space become closed curves. A geodesic is the shortest path between two points considering the curvature of spacetime, and which is followed by light, and in GR, it is described by the geodesic equation:[math]\frac{d^2x^\beta}{d\tau^2}+\frac{\partial x^\beta}{\partial \xi^\alpha}\frac{\partial^2 \xi^\beta}{\partial x^\mu \partial x^\nu}\frac{\partial x^\mu \partial x^\nu}{\partial \tau^2}=0[/math]Physically, this means that if light is shone along these geodesics, it will move along closed loops which are actually the geodesic projections in three-dimensional space. In other words, light would keep circling the body along these curves! And such a curve with the minimum radius (i.e. closest to the centre of mass) is what we call the event horizon.Within this radius, it can be shown that all geodesics for bodies with mass lead right into the centre of the black hole - no matter how much these geodesics are linearly warped by supplying the body with kinetic energy. So any body is trapped within this region bound by the event horizon!

I’m a woman working in STEM field and I’m going to give you my honest opinion. It could be unpopular, sure, but it very well is coming from a woman and I think that perspective is sorely needed in this thread. <looks around at the thread with a laughable bias>I’m going to mention Dale’s answer, since it’s a bitter pill in a way because yes, the interest/passion I see from women in pure technology and abstract programming is lower than what men have.And I’m going to give an answer that doesn’t occur to most, at all. They can definitely observe from the sidelines, they cannot experience what we do.However, since Dale didn’t mention it, I’ll say the most important thing:Men are not better at programming than women just because they are men.Men really need to thank their goddamn stars for being born a guy. They have their issues, but when they say they have issues, people consider those as issues!I’ll just list down my thought process to make it simpler for you.I took a pause after reading his answer and thought a bit. I could see the several feminist pages I support encouraging little girls and women to take up STEM if they want to. But the result would not always be equal. Is it really something lacking in women? Are men now going to take this observation and cackle about ‘told you so?’.Then I looked back on my life, where I was studying in CS in Uni. I looked at the difference in the way guys and girls behaved with regards to technology. I tried to find any significant difference in the attitudes/behaviors/surrounding factors.Key differences:The way women and men are treated when they have interest and passion for something is totally different. From my observation - me holing myself up to do a project was seen as a problem. A big behavioral problem - since it affected my social life, my looks and my femininity. Nobody likes a girl like that! Keep telling that to a young girl and she’ll end up re-routing her whole life around being liked instead of focusing on a passion. Just like many women you see around yourself. My family loves it when I pursue something with passion - up till a point. Once they think I’m being too anti-social, too nerdy - it has to stop.Then I’m supposed to start worrying about marriage, kids, how this behavior will never be accepted by guys or their families. Who wants to date/marry a woman who will sit quietly and do her thing without looking twice in the guy’s direction? Many guys I dated have taunted me about the kind of absent mindedness I have when I am working on something and don’t want to be disturbed. I have been called selfish, unfeeling and emotionless - qualities I am supposed to have because I am a woman and dumped over them several times - resulting in me abandoning something I liked for someone’s approval. The amount of messages women get from society about how women should carefully tread and take the ‘safe and comfortable’ route so there’s no problems later - they have been hammered into our heads since a young age. Adventurous is a word positively used for guys - we were told to avoid being seen as ‘adventurous’. From what I know, men have no clue how much this affects women’s decision making. Even when they are similarly affected by social conditioning in other areas, I will definitely find men saying in the comments section how ‘Well if she really wanted it….’. . Allow me to roll my eyes at your obvious confirmation bias. Women are repeatedly told to think about others, NOT themselves. Women are repeatedly told to ensure their decisions should not cause them problems with future guys/in-laws. Women are repeatedly told that the path in these careers will be filled with problems for them. And believe it or not, this WILL affect a woman’s decision when she approaches a stall where you advertise a super-interesting but challenging core technology course ~only for women~ - and she will run through all the future scenarios and generally chose the safer, non-challenging route because she’s brought up to believe this is the best for her - and you will be left wondering why they don’t. Then you’ll shrug and assume, maybe they’re just not interested.Note : If you think years of social conditioning can be brushed off with 2–3 posters of ‘girl power omg!!!’ then I’m sorry, you have no clue how social conditioning works.I was never encouraged to be better at something. I had to develop that on my own. I was never a part of the boys club that gathers around late night - while I had to head home. I was given a lot of instructions on how married life will be easier if I get a comfortable job instead of a challenging job. How I have to follow my husband anyway. How I will be taking care of the kid because men have to do everything with passion, you see - women have to do everything and then if there’s some energy left - follow their passion - only if it’s socially approved though. My seniors - male ofcourse - surprisingly women don’t say such things- kept saying ‘Women are not suited for this, they’re just here to pass their time’. They’ll refuse to discuss new projects with you. They would give me non-challenging work while the challenging work was passed on to ‘the lads’ who could sit guzzling coffee/diet coke overnight with them but I had to head home because as a woman I was given a curfew. “We can’t keep a girl in here so late”. “We can’t take you on since you can’t give as many hours to it as him” - him being a guy who obviously had no curfew, no restrictions, no biases against his gender, and all the support to pursue his passion. I sometimes wonder - when a guy expresses that he is interested in STEM - is he given any cautionary tales? Any discouragement? Any cues as to ‘this will be a disaster for you because what it takes ro succeed is not going to go well with women?’ Any ‘alternative safe options’ since you have to think about how it will be after marriage and kids?The kickass women coders I know, had to face a lot of challenges to be taken seriously. People assume they copied it, some guy wrote their code etc etc. They don’t really want to believe these women got it. Such attitude wears them down a lot.I’ve also seen how it’s easy for guys to dismiss these points when I say them. So obviously I don’t. So they never hear it again. Ergo, what they think is obviously right, in their heads.For guys, all these points are seen as ‘She just didn’t try hard enough.’ The problem is, they don’t really think much, since it doesn’t require a lot of brainpower to assume things. So far the assumptions range from ‘she didn’t try enough’ to ‘she could overcome social conditioning if she really wanted it’ to ‘women just don’t have enough brains for this’. I chose to be amused by these because I’ve seen these excuses made for a long time.When I talk about social conditioning and how it shapes society- if it’s in favor of men, I see support from men. When it’s in favor of women - not so much. I see a lot of ‘alternative points’/ ‘devils advocate points’ being made for women just not being good enough. I see a lot of men (always men, hmm) trying to explain how I am obviously wrong, how I’m missing something and it’s not really sexism or social conditioning… how it’s just how we are wired. They are literally begging to convince me that women ‘just don’t have what it takes maybe?’ (and maybe you’re not seeing it because you’re a woman and we all know women are …ahahah?)I don’t see the same being done for men. Just an observation.Conclusion would be : YES. Women have lesser interest in STEM currently. There are lesser women who are great programmers than there are men who are equally great. But there will be a time when this question will not be asked, because hopefully the social conditioning will not be the same as it is now. Maybe society will get better, and we won’t place mental and emotional obstacles in front of people due to their gender - and we’ll see what happens.Does this answer if men are better at programming? Currently, as per my observation, yes. We’re not there yet. Encouraging girls into STEM in the last 10–20 years is nowhere close to the sexist social education they get. Try for another 20–30 years. The maybe this question will have a different answer.Bonus: People who claim social/labor equality can be achieved instantly due to a few decade-old ‘equality’ laws, after centuries of sexism and gender based social conditioning - are delusional or just not rational enough or both.

The primary purpose of cache is to provide some sort of hierarchical memory system , with the cache serving to reduce the average memory latency. This is done by keeping frequently accessed data or instructions in a high speed pool of memory .In a sense , the cache doesn’t really help the RAM at all , it’s more closely linked to the CPU core itself . The cache and DRAM controller within the memory sub-system of a processor are actually fairly decoupled from one another , with the IMC receiving requests out of order , and only when said data isn’t in cache .But caches can help a CPU make more effective use of it’s memory resources , at least as far as bandwidth is concerned . This isn’t addressed as often as the obvious access latency benefits however .Consider a basic cache , like what you’d find on a 486 from the 1990s. Such a cache really only provides the latency benefits mentioned above , but that’s not all a cache can do. The cache on a 486 is known as a write-through cache. A Write-Through cache will updated itself and the main RAM simultaneously on a cache hit when being written to. It’s easy to design and coherency isn’t a problem .But consider that roughly 50% of x86 instructions involve memory accesses , with about a third of that being memory writes . All in all , that means roughly 20% of x86 instructions are memory writes. This shows when you look at the back-end of modern x86 processors , with roughly half the execution ports being for memory access.Intel Sandy-bridge µarch backend. Notice that ports 2 , 3 and 4 are dedicated to memory accesses. Image from Intel’s website.From an architecture design standpoint , going off-chip is expensive . It’s expensive in terms of power because you need to drive memory data and address lines access relatively large distances, and it’s expensive in terms of performance because the distances involved are huge from a processor’s standpoint , which means latency is a problem. Thus , limiting DRAM accesses is in the architect’s best interest .What’s more , memory bandwidth to DRAM is also quite a precious commodity, with modern processors needing to share a couple dozen GB/s of bandwidth across multiple cores. Thus , there is real gains to be had in limiting unnecessary DRAM accesses and staying on-chip as often as possible .I mentioned write-through caches and their write policy . As i also said , writes account for roughly 20% of all x86 instructions . This means that you’ll be spending roughly 20% of your time writing to DRAM with a write-through cache. This isn’t ideal for 2 reasons :Writing to DRAM when that data is going to be read from cache in the near future wastes power and bandwidth.Your CPU will usually need to wait for the DRAM write to occur before continuing on with it’s operation , which slows things down .But there is a better way . Modern CPUs typically employ a Write-back cache for their L2 and L3 caches . A write-back cache works like this :No difference for data reads vs write-throughWhen a cache hit happens on a write/store , the data in cache is updated . However , DRAM is NOT updated . A “dirty” bit is set in the cache for that particular cache line, signaling that the DRAM is not consistent with cache .DRAM is only updated when that cache line is evicted , if the dirty bit is set .Write-back caches solve many of the limitations of write-through caches. These caches save power , improve performance and help the CPU make better use of DRAM bandwidth. But that doesn’t mean they don’t come with their own headaches.For starters , write back caches allow Data in RAM to be different than what is present in caches . This isn’t much of a problem in a uni-processor system , but for multi-core or multi-chip configurations , this means you now have to be able to track who has the most up to date data , which involves a complex cache coherency protocol , which can quickly increase complexity substantially . Plus , they are generally more expensive to implement than a Write-through cache.In the case of a multi-core system , this might mean that a core might need to come invalidate data within other core’s caches , or go grab data from another cache . This is expensive and messy , which is why L1 caches are typically write-through ( they update the l2 and themselves simultaneously).L1 caches are usually quite entrenched within their core’s pipeline , so having other cores come mess with it during operation is generally bad for performance.