So you're applying for a UX role, sent off your portfolio but why do you still need to do a design challenge? A portfolio is a designer's best work. On the other hand design challenges are meant to 1. Get insight into the designer's process. 2. Give the opportunity for the designer to ask great questions. 3. Understand if the designer can work under pressure. 4. Get an accurate sense of the designer's skillset.


What's up everybody, Jason here for JaspysCaseBrace.com. 2022, Panini Honors Football just sold out. This is a two box break, random teams number one. This is a, how do you release, they released a week or so ago online exclusive and we were able to snag the case. And again guys, 32 total spots, all teams in. Very high risk, high reward guys. Only four hits a box. Two base or base parallels. One other autograph and one recollection collection. Graded card are non-graded original autograph. So the recollection collection autographs are very, very nice. And there's an example there that Patrick Mahomes rookie. So, here's the dice roll, here's the customer names, all 32 in, all teams, roll, full 12, I love it. We've been rolling a snake guys, then we got 12s. Six out of six. One, two, three, four, five, six, seven, eight, nine, 10, 11, 12. For people that hate snake guys, at least I love this. All right, 12 times. One, two, three, four, five, six, seven, eight, nine, 10, 11, 12. Seahawks, out of the chargers. So Steve with the Seahawks, Patrick with the Packers, Alexander the Lion, Steve with the Raiders, Dean, Bucks, Steve, Colts, Alex, Commanders. Ryan with the Jets, Matthew with the Eagles, Ben with the Texans, Chris with the Patriots, Michael with the Chiefs, Ed with the Panthers, Chad with the Titans, Eugene with the Saints, Adrian with the Jaguars, Sammy with the Giants, Anthony with the Vils, Chad with the Dolphins, Josh with the Bears, James with the 49ers, Patrick with the Vikings, Nicole with the Bengals, Joe with the Rams, Andreessen that is, James with the Ravens and Cowboys, Jordan with the Falcons, Victor with the Browns, Eugene with the Browns, goes to Eugene as well with the Steelers, Steve with the Cardinals, and Brian with the Chargers. And again guys, honestly I don't really think there is a bad team in this. Now of course, for the 2020 Drop Pigs, some teams are better than others. But there is a lot of recollection collection cards where again, if you go look at the checklist guys, there's a lot of hits for a lot of teams.  There is a ton of hits. Let me see if they actually show us the whole team checklist. But like I said, a lot of hat numbered one-of-ones for a lot of different teams. And yeah, I guess they do have team sets right here. So check it out guys. A lot of different teams are here of course. I'd have a chance to get some really, really nice hits. So obviously there's examples there. There's Jalen Hertz, Jordan Davis, and then you can see a lot of those other ones. Also too, I think, let me see if they show you the recollection. Once I see the recollections there, let me see if Carbon Connection shows it. 2003 honors base. Yeah, non graded originals. See that, I guess they can't tell you the card because they don't know exactly the card, but they'll tell you how many different ones they have. Like the non graded ones, recollection collection set from AJ Browns. There's like so many different AJ Browns, so many James Connors, so many James Washingtons.  So of course you can see your teams there potentially there too. But yeah, I'll give it some time if you guys want to trade, but I understand though. I guess a checklist is a very, very deep checklist. Probably a lot of different ones. All right, I'm trading, well I'm trading with them, maybe a little too late for some people. All right, let's see how good this is, guys. Hopefully we get some banging boxes, but if we don't, that just means there's banging boxes remaining. So again, minus the rookies in this class, you have a chance to get those recollection collections. So I did close up another one. We can always run one back tomorrow as well. It's a pretty high-end box actually, it's like 900 bucks a box or so. So obviously, pretty priceless, that's why we're only doing two box verdicts. But, one, two, three, four, five, six, seven, eight, nine, 10, and let's generate two numbers here. All right, first one, six. So one, two, three, four, five, six, the top box on the right, and let's generate another number here. Four, one, two, three, four, this box right here. Now these ones here will be for the next break, which we can run back tomorrow, guys. And again, if you guys didn't want to technically do a personal, just buy out the break and then a personal box break, two box break. All right, here we go, guys. First one. So usually, if I'm correct, they have two cards, one on the left, one on the right, and then usually, they have the pack in the middle. So I'm gonna pull out the pack, and we'll leave the cards in there. We'll go with the two basic inserts. All right, first one we got here is Kenneth Walker and a breeze hall. And the Kenneth Walker is numbered 45 out of 75. And then the breeze hall for the Jets is numbered 12 out of 15. So Ryan with the Jets. And then, of course, Seahawks is Steve Harris. And a lot of people love to grade these cards too. They grade pretty well. All right, here we go, first one here, guys. Let's go with the top card that I pulled to the side. And it's a Drake London rookie autograph for the Atlanta Falcons Jordan with that one. That's 10 out of 49. Pretty nice, pretty nice. Nice Drake London there. And your recollection collection card is a one of two Fletcher Cox for my Eagles, Fly Eagles Fly, Matthew P. So again, they probably had a couple of these lying around. Nobody cleaned them as a damage card, so then they stamp it, recollection collection. We have two of them, hand numbered to two, and there you go. So there's the first hit right there. Next one for the 49ers. And a nice Sam Howe. Love the design on these cards this year too. They look really nice. Sam Howe's 19 out of 25. And then the Brock Burdy, James with that one, and Alexander with the commanders, 29 out of 75. All right, so like I said, only four hits. Here we go. We have a Elijah Moore, and that is actually a Originals. So 23 out of 25. So this is one of the original cards. They probably had an extra one out of 25 lying around. There you go. Nice one there for the Jets. Going to Ryan. So no crazy one-on-ones maybe out of here, but there's definitely probably some hiding in there guys. There's usually a lot of one-on-ones in this. And then this should be your normal rookie. Wow, what a break for the Jets. Garrett Wilson. 29 out of 49. Awesome. Jets, Jets, Jets, Ryan. What a break for you, buddy.  So nothing super crazy out of the recollection cards. Definitely feel like there's some huge monsters hiding in there guys. Like I said, there's a lot, a lot of one-on-ones, a lot of different cards. So definitely some big hits hiding in there, but nice little introduction right there of what we could potentially get out of there. We've got two good receivers on the rookie side. Then Fledger Cox and Elijah Moore, of course, on the recollection and the original. So appreciate it guys, that was it, just like that. I did post up another one. If you guys want to run it back, it is on the website now again, jaskyscasebreaks.com.


All right Welcome, so we did quiz two and now we're at the home stretch where today's lecture should be fairly easy So this should be all We can take a deep breath and we can learn what an MMU is today Cool Which will take like two seconds All right, so today we're going to start talking about virtual memory So remember what? virtualization is and virtualization is just the concept of fooling something into thinking it has all the resources So if we have two processes like Libra office and Firefox, they both think they have all the memory and They can have access the same virtual address which corresponds to a different physical address and The kernel is free to do whatever it wants with the mappings that can do something smart like making sure that for example Lib C, there's only one copy of Lib C in physical memory and Wherever Libra office thinks it's loaded and Firefox thinks it's loaded actually point to the same physical Addresses and it just shares by default and you only have to load one Lib C instead of like 200 of them So if we're designing and trying to create a virtual memory system This is kind of our checklist of things we would want We want multiple processes to be able to safely coexist We want processes To not be aware whatsoever if they happen to be sharing virtual memory So everything should be nice and transparent and then processes shouldn't be able to access each other's memory Unless you explicitly allow it so we can do something like explicitly share memory between processes to get some IPC between processes, but by default that should be an opt-in thing and By default everything should be completely independent You also want performance as close as possible to you actually using physical memory otherwise you would probably just suck it up and take all the drawbacks with actually using physical memory Because if it was twice if using virtual memory was twice as slow or ten times as slow Then no one's gonna use it So you want performance to be as close as possible and we'll talk about that in the next lecture and Then the last thing is you want to limit the amount of Fragmentation and that is a new word that will revisit a few times as we would talk about memory allocation and stuff Fragmentation is just the amount of wasted space. So if I allocate, you know an Integer and then something else that's bigger and they have to be aligned that like 16 pages I might have a gap of like 12 bytes that I can't use and that would be an example of fragmentation But don't worry about we'll visit it again As we talk about allocation So now the MMU this is what it is so all it does is map virtual addresses to physical addresses and Also does some basic permission checks like for example if I try to write to some memory I might not be allowed to write to it or I just might not be allowed to read it or I can't execute code from it so the MMU would do all the translation for you and Check all the permission bits and that would be done in hardware so one technique we have is to To actually do this translation if we had to do this translation for every single address like every single byte It would be horrendously slow so what we do is we divide memory up into bigger blocks and they call them pages and Each page is typically 4096 bytes which is a nice, you know power of two and It's been like this since like the 70s So are your Linux system your Mac system your Windows system? They all use this page size still and it still works quite well so we there is You can adjust it a little bit depending on the hardware, but for the most part that's our page size and that's like The unit that your operating system deals with memory in so whenever I create a buffer I made it this size because I know that the Linux kernel likes things to be that size and Typically deals with memory in blocks of that size So that number is going to be an important one to remember. It's 4096 or 12 or 2 to the power of 12 So there's some kind of weird terminology here, so This fixed-size page is Called a page Generally if you're talking about virtual memory It's called a page and if you're talking about that same block of memory as a physical page Sometimes they just call it a frame or a physical page, but they all mean the same thing But by default page generally means a virtual page, but they're all going to be the same size Okay, so now we can talk about Segments, so this is like a very coarse-grain way to do virtual address translation so you divide the virtual address space into kind of different Blocks of memory that might have different permission so you know need to live somewhere different so you might have one segment for code which is anything you need to read and execute and then just Global data that is loaded in with your program that you probably At least need to read from but you might need to write to and then stack in the heap Which is all read write and it kind of looks like an elf file image where there's just sections of code And it says hey load this these are the permissions you can read and execute this So with this you have a limited number of segments in this example There's four and they're each variable size and you can dynamically resize them and this is like an old thing That's no longer used whatsoever, but operating systems like to talk about them for historical reasons So they can be large and really costly to relocate so if you have two sections that are right next to each other and You want to make the first section bigger so it might overrun the next one Well to do that safely you have to take that whole section you have to move it over you have to copy all the memory and then you're allowed to make that other section big and You have to be responsible make sure things don't overlap and it's just a huge mess and it's kind of terrible So it's no longer used in operating systems, but we get a fun vestige of it where The segmentation thing Whenever you access invalid memory and you get a segmentation fault even though there are no Segmentations that that's why it's called that so historically it was called a segmentation fault Even though it doesn't use segments anymore, one of you access invalid memory still called a segmentation fault for Historical reasons, but so that's whenever you access a null pointer or do something you shouldn't have so that's where that comes from So just so you can see what it looks like so each segment generally has an entry that Corresponds to where it is in physical memory so it will have a base address and then a Limit to say how big that segment is and then all the permission bits and then whenever you want to access a physical Address your virtual address looks like this where it's just a segment selector and an offset So it's like I want to access, you know bite 255 of segment three or something like that Then what the MMU is going to do again remember it's responsible for doing the translation It's going to check that your offset is within the limit for that segment So that it is valid and it falls within the side basically like an array bounds check And then to calculate the physical address it will just add the base address to that offset and then do the do the permission checks and If it fills any of these steps That is a true og segmentation fault and not like the reuse term that all of our programs have done at one point or another So for example if you have this as your virtual address where you say I want segment one and I want offset Ff well first it's going and the segment One has a base of two thousand and a limit of one ff. Well, it's going to check to see if the size is within so Ff is less than one ff. So it is within bounds. So to calculate the physical address It's just going to add the base to the offset and then that corresponds to the physical address to zero ff Pretty simple. Yep. Yeah, so under this it's all contiguous Yeah, yeah when we get to the page table, it just deals with pages. It doesn't care.  So Everything just maps one to one. So it they essentially disable it because your x86 hardware is still going to support this for some ungodly reason because they can't take it out. So They're smart and they essentially just disable it. So all of our systems are pretty much 64 bit machines Which means you can like support up to like 16 exabytes of memory, which no one has So you can actually do something a bit smarter when we do we can put aside some bits We're not going to use all that memory anyways When we do our address translation so CPUs have kind of different levels of virtual addresses how big they support and what it maps to and Conceptually they're all the same. It's just the numbers are going to change slightly so For this example, I'll just assume that we're using a 39 bit virtual address Which is used by risk 5 and some other architectures like arm uses it I think you can optionally use it on x86 But this allows for a good balance where it the longer the address is We'll see later that the longer it takes to translate it. So generally if it's big enough you say, hey It's good enough. So this allows you to address up to 512 gigabytes Of memory which is a lot of memory that's more memory than I have but you know, eventually you'll have to adjust this so how this is implemented is with a page table and it is literally just a lookup table so it's indexed by the virtual page number and You just look up the virtual page number and within the page table entry One of the things in the entry is going to be the physical page number So if you want to translate a virtual address to a physical address You just replace you look up the virtual page number and then replace it with the physical page number And then suddenly you have a physical address so And we'll see an example quick, but this is basically what it looks like so our virtual address if we are using a 39-bit virtual address it's going to look like this and remember our page size is going to be 4096 so that's to the 12 so we're dealing in pages of that size So we're not going to translate the lower 12 bits because that's the size of the page so the offset would be between 0 and 4095 so we don't translate that that's within a page and It would be the same, you know We line up everything by pages so if in our 39 bits we use 12 for the offset it means we just have to translate the 27 bits Yeah, so we would use the 27 bits for our index and that would go in our page table So our page table would have two to the 27 Entries and then each entry in this case each entry is actually Eight bytes so we know how big our page table would be so it'd be two to the 27 entries times two to the three Bites which seems pretty big because it would be two to the 30 Yikes, but we'll get into that Okay, so let's see how you actually do this translation. So we'll just assume that Our page size or sorry our page size is the 4096 so we don't have to touch The lower three bits and we'll just have four entries in our page table So let us go back here and see so this is going to be our page table in the blue box here So we're just going to have three entries in it. So entry zero one two and three and Then they're going to correspond to physical page numbers and They don't necessarily have to be contiguous. They can be all over the place. So if we go ahead. Yeah The segmentation is Yeah page tables are still used not this because this has drawbacks that we'll see but at the base base of everything This is basically what happens So we'll see what really happens next lecture, but if we want to do Translation of these then well if I want to translate, you know zero a b zero well luckily enough each hex character is four bits and My page size is to the 12 so the last three hex digits are all part of the offset So I don't have to touch them whenever I translate So whenever I translate to from virtual To physical I can keep the offset the same because we're not touching that and Then I look up the Here this is the index So the index is Zero so I would just look up in my page table here and then find out a zero zero maps to physical page One so I just replace zero with one So that would be my physical address yep, it would be if your page size is 4096 So in some questions they might be we'll see later. It's like hey the size of the page is now this and it gets more annoying Yep, so the MMU is doing the translation the kernel is managing the page tables So it's doing the translating, but you have to Do the mapping yourself Yeah, so the kernel is managing the page tables and the MMU is just dumbly using the page tables and doing all Translations for you So in this I don't say how big a virtual address is for this Virtual address could be like 14 bits. So it just takes up to So yeah for this I shortened it because like we'd have like 39 a real one, but I don't want to write 39 characters or 39-bit address Yeah, yeah, so in this The amount of memory your process has is how many like valid page table entries it has so in this case if our page table is only four and They were all filled up and all use that means our process because can use four pages Which is what like 16 kilobytes, which isn't that much. Yep Okay, so Anyone want to translate? One f a zero for me it would be four F a zero. All right, everyone agree Because we took the offset Left it the same and then when we looked up zero one It was this page this physical page number and we just We just swap them Okay So what about two eight eight four zero in zero three eight eight Four okay, what about three two D zero and seven two D zero and This is basically how it works So it's just a simple lookup. Yep Yeah, sorry So the MMU just uses the page table. Yeah Yeah, yeah, the curl manages the page table So it would you know the curl would load things into physical address and then if that process says Oh, I want my entry address to be 2000 something like that it would make sure that that virtual address maps to that physical memory when you want to access something it's just as As part of your process each process will be using a page table So somewhere in your hardware Generally, it's like a register that points to the page table and you just swap that with the process And then the hardware just takes care of the rest So it will use that page table whenever that Process accesses memory Yep So the kernel manages the process is page table And it would be protected and all that stuff So that's like one of the core jobs of a kernel that nothing else gets to do Only the kernels allowed to modify page tables user processes can't begin to sniff it Because it you're only allowed to do that stuff in kernel mode So even if you have a small micro kernel the micro kernels going to manage virtual memory and manage all the page tables Okay, any questions about our fancy lookup table. Yep. Yeah. Yeah, it's all all in kernel The page tables are all in kernels magic or kernel space. They can't touch them and it just The kernel would be responsible for setting up that page table to point to the right thing when it switches processes And then hardware is just going to do all the translations and If you do something you're not allowed to the MMU is going to generate a page fault and then you get a Oddly named segmentation fault even though they don't exist when really it's a page fault Yep Yeah, so the question is is there a shared address space between processes so you can opt into shared memory where When before you fork you can set up a region of memory that's you know You indicate to the kernel is shared and that whenever you fork it shouldn't be separate It should actually use the same memory. So you are allowed to do that Yeah, yeah, everything's gonna be going through the MMU all the translations done by the MMU and all the page tables are managed by the kernel So as long as your kernel doesn't have a bug you're good Yeah Mm-hmm. No, it's virtual memory. So your process only uses virtual memory. Yes Yeah, so yeah, that's a good observation that this page table here would be on a per process basis So this could be you know This could be process One and then process twos page table it would have all the same virtual page numbers So it would be you know one two three Four and then here say let's go five six Two and zero so now These are all four Process One and this would be for process two So now if we translated the same virtual address of like zero a b a b zero in process two Well, it would get the physical address Five a b zero So each process would have its own page table and then the kernels responsible for doing all the mapping So it has to keep track of things if it wanted to share memory between the processes well then instead of Mapping to different physical page numbers. I could do something like this So they translate to the same physical address, but to have sharing be safe You typically would make sure that that page is read only Otherwise, it's kind of the same idea as a race condition One would be able to modify the other two and there wouldn't be that clear independence between them But that's basically how it would look Yeah Yeah, yeah Yeah, you're getting getting ahead of us. Yeah. Yeah. Oh the Ford Yeah, yeah the first two bits Yeah, the the three hex digits at the end are just the offset because they fall within the page so Page is four thousand ninety six. That's two the twelve. So three hex digits Which makes it easy. So we'll see when it's not nice, but when it's not nice, we all know our binary, right? No Okay, well, everyone should practice their binary. It's all good stuff So here's going to be our problem where it's not too nice. So this Questions like this will basically give you all the details They'll say how many bits are in your virtual address? How many bits are in your physical address and what's the size of a page? So For this it's really good to know your powers of two off the top of your head Like a good one to know is to the five is 32 and then based off that you can make steps and kind of easily go to other ones so If you have a eight-bit virtual address that means you have two to the eight possible Entries there that's two to the eight bytes you can address and if you have a physical address of ten bits And that's two to the ten and then if each page is 64 bytes What's two? What's 64 and two to the power of something? Six, okay, so knowing that and how to do math with exponents How many virtual pages are there? so What is how many bytes it can we represent with virtual addresses if there are eight bit ones? Two to the eight, right? So Yeah Yeah to the eight divided by two the six so to the eight because that is how many Virtual addresses in total we have and then each page is 64 bytes So we just divide total by the size of a page and that's how many entries we should have Yep, so this is eight bit which can represent to the power six bytes because we're assuming byte addressable systems We've only seen byte addressable systems So to the eight bytes in total divided by to the six bytes for a page Means we can have to the two or four total pages Everyone agree Okay, well then how many physical pages are there? Yep for pages Yeah, how many physical pages there would be? four 16 right So 16 because for a physical address there are two to the ten of them to the ten possible bytes And then it's just divided by the number of pages again so What yeah So that's a that's a good question So if I don't have if I have more physical addresses or physical pages and Virtual how can I map them all anyone want to take a stab at that because that's a really good question? sorry you You each process could use it a but how many processes can we have? We might have lots of processes So all across all the processes they could actually use all the physical memory if it's bigger so Right, so in this case We'd have 16 physical pages so to the ten Possible physical bytes we can address divided by the size of a page So that's to the ten divided by two the six which would be two to the four which is 16 so that means We could have four processes and then four processes could each have four page tables And they could fill up all the memory it would be slightly weirder if you do the other way where you have more virtual addresses and physical addresses because Then you suddenly you still have more virtual addresses you should use but you ran out of physical memory a long time ago Or can't support that much physical memory Yeah So when you context switch the process it would swap the page tables to I mean the night but No, so it's large enough that there's each process would have four virtual pages that can use and There's 16 possible physical pages So then each one would have its own page table and then just do that normal mapping So it'd be like the same Thing as before actually that pretty much exactly lines up So in this example where I wrote out two page tables There's two processes that had full page tables But there is no collision in all the physical addresses so Yeah, so they're using the same virtual address, right? So If I translate zero a b zero For process one it's going to be a different physical address and if I translate it for process two Because it's using a different page table So with an 8-bit virtual address and a 10-bit physical address I could actually support, you know Four full processes and give them all memory Okay, good question. So I go back So kind of jumped the gun But how many entries in the page table it will always be the same as the number of virtual pages because you have to look them up, so there's just four and then The next one that is as hard as it will get today is Given the page table This so this is just a shorter way to write the page table. So it's just index So this is index zero index one index two and index three So those would be the virtual page numbers and then these are the physical page numbers So in this case it asks you to translate the physical address of f one one So if we go to that Yeah, so who knows what it is what okay, so So it is two Zero f1 Yeah, anyone agree sag fault This is mapped it's not a sag fault. We can look it up. Why why isn't this map? Why do you think it's not mapped? Yeah, so this is So these are our virtual page number so It's not mapped f isn't mapped where do you get the two zero from? Yeah, where do you get the two from? Oh, you think this is the same as That So then we just take this Copy it and then zero This is maps to two Okay, that makes sense so If I just copy the last three hex digits How big is the page a to one virtual oh Eight two one. Oh So how'd you get eight two one four? Okay? Okay, and then we added them Okay, so these are this is a really annoying one because the number of bits For the page is six. So it's kind of annoying where it doesn't line up for hex digits. So We have to resort to writing in binary So this will make it easier even though it seems awful. So F1 F1 is if inner eight bits is one one one one So that's f and then one is zero zero one two two one closer So we'll see so here so first We don't touch the offset and now we know our offset is six bits So this is our offset. Oh Okay, so the question is why do we know it's six Why do we know it's six bits? Yeah? Yep, so we know that's the offset because our page size is 64 bytes, which is the same as to the six so Same rules apply. It's just in binary now. So it's kind of crappy, but our offset for our This is our virtual So when we translate to a physical address They're exactly the same so they would be one one zero zero zero one and These are our same offset bits So in that spirit, this would be our index and Then our index that's a three. So one one is three so it would correspond to this entry here, which is eight and eight is Unfortunately one zero zero zero so if we write them all together like that. This is our Yeah, yeah, so this is our 10-bit physical address so it's we can double-check ourselves that it is 10 bits So if we group them back up into fours and write it back into hex Zero zero one that's a one Zero zero one one that is a three and then one zero is a two So this would be our virtual address two three one Everyone on the same page Terrible so in this there is four Yeah, it's the index. It's gonna always be the same as the number of virtual pages And for a single level page table. Yep the first two bits for the physical so we just Looked up the entry the entry was eight. So eight was zero zero They're one zero zero zero. So this is eight So we just put that at the front. So this was our offset here And then we just wrote eight in front of it here So when we combine them like two of the bits were from the eight and two of the bits were from the actual offset So it was a three. Okay So Usually this is actual hardware. This is like in documentation So there's a bit more in our page table So so far we just assumed that The entry in our page table was the physical page number But because there's this offset we don't have to translate essentially we get 12 bits for free we can play with So this is at least for risk five That they reserve 10 bits to be used for permissions and things like that So there's one bit that says whether this page is valid, which is useful when you drew translation so instead of Deallocating it and trying like zero memory or something like that you can just say hey the page is no longer valid So then whenever the mmu translates it it generates a fault and it fails So other Like for the purpose of this course, we only really care about probably the first four bits maybe five Um readable if you can read the memory or not writable if you can write the memory or not executable If you can actually execute it So, you know your cp you can read it and as instructions And then there's going to be a bit that says whether or not this is represents user memory Or if that's not set it's kernel memory So it's just another way as another security check just to make sure everything lines up so These are the entries that the page the mmu actually wants So it's we'll take the physical page number that we saw and then they also ram a bunch of permission bits that the mmu will check for you So we only really care about the first five fights for this course, but this is like actual Hardware, this is what a page table entry looks like so We kind of jumped the gun on this so each process gets its own page table Which just represents its own virtual address space so for Some processes it would look like this where user text and data is at the bottom which is Text is a really dumb name. It's actually code So it's things you can read and execute and then data so that would be global variables and everything that's you know essentially Global data defined in your c program and then there'd be some space for a stack space for a heap and then the trap frame is this is like internal details for a little toy kernel But the trap frame is basically Where the kernel will save all your registers and stuff when it does a context switch So it saves as part of your virtual address space and trampoline is just another thing to Mechanism to switch between user mode and kernel mode that we don't really have to worry about so Each process also gets its own page table. So we know this so now we can figure out what fork has to do so If you fork one of the things we know it's the exact copy of the process So that means if each process has its own virtual or own address space And they each get a new address space when you forked and everything's independent Then it has to copy the page table so If in the naive Way it would copy the page table and then copy all the memory that the page table points to so that everything's completely separate But if you are a smart kernel developer well If you have pages that are only red Essentially, they can share them no problem because you won't see any changes in the other process So if they're readable pages, I don't have to bother copying them I can just ignore them And then there's this trick called copy on write so if I can copy them not copy the physical pages and just turn the right permission off And then whenever one of the processes modifies that memory I get an error and then as the kernel I get to resolve that error So it would generate a page fault and I can be like oh Well, I know I made it generate that because one of them modified some memory So then at that point you can make a copy of that page And then make them point to different pages where one has the modification and one has the original copy And that way you're only copying memory that you actually need to write So it's a nice little easy optimization you can do Yep Yeah, yeah, so that's the secret fork is fast But if you start using the memory and monkeying with it, it's going to have to do the mappings kind of on demand It might be a bit slower, but It's better to just only copying the memory out like an on use basis Yeah Yeah, so that's a good question So what happens with the execs ve so exec ve says you up with a new address space so it starts a new page table from scratch Yeah, like it just replaces the page table So old one gets deleted and it just replaces it So The big problem here is if we use a big single page table Where we have even a 39 bit virtual address, which isn't even that big That means there are two of the 27 entries in the page table each one is eight bytes So if we do our multiplication that means each page table is a gigabyte So obviously that can't happen. So How many processes could you have each process needs its own page table and each one's a gigabyte? That seems like I you could probably run at most like Eight processes and then half of your memory is filled up with page tables So we must be we must have a better technique than doing this so And yeah, then the So that's where we'll leave off for the next lecture and then risk five It would be at least one gigabyte. So we'd have a 39 bit virtual address And in risk five it translates to a 56 bit virtual address Uh and generally they'll all be bigger So it has 10 bits to store the pte and then Reserves some bits that it could use for later expansion And but the page size is still 4096 So you may be thinking that also seems like a lot of work If you're doing fork fault followed by an exec, which is what you just mentioned Why don't you even bother copying the page table at all like i'm just going to delete it immediately So They don't and that's why they invented another system call called v fork So v fork shares all the memory with the parent. It doesn't touch the page table But it also gives you this caveat that if you touch memory in the child process It's undefined behavior and you can screw up the child the parent process So that's pretty cool. So only use this in like very Sensitive applications that really really depend on performance and that immediately exec And this is why they got rid of Adding a whole bunch of other system calls and just essentially made a new system called called clone that lets you control What gets copied? All right, so I will leave you off on this and this is how it's actually used and what we'll be talking about next lecture So instead of having a big single page table The trick is to have multiple levels of page table where they point to each other and each smaller page table Exactly fits on a page. So that's what we'll be talking about next lecture So, uh, let's remember boom for you or all this together


Shalom and praise the Lord, everyone. Thank you for joining class. Welcome all our online students and also welcome to our e-learning students who will be joining class or who will be listening to this lecture later on. Before we look into receiving God's guidance for our live, the publication, can we just pause for a word of prayer? Can one of our online students please lead us in prayer? Anyone can lead us in prayer please? Can Esther, anyone can lead us in prayer? Esther, Deepu, Oramita, can one of you unmute your mics and lead us in prayer please? Jennifer, Jayram, anyone likes to lead us in prayer this morning? Good morning ma'am. Good morning Esther, please. Hallelujah. Dear Heavenly Father, we thank you for this wonderful morning. We thank you for the session of Lord. We thank you so much for your wonderful grace over our lives. Lord, we are going to begin the classes. Lord help us open our spirit of understanding over the word of God. Lord help us to grasp everything and hallelujah, grow in our spiritually. Hallelujah, help everybody to grow in our spiritual way, Father God. Hallelujah, strengthen our inner man. Hallelujah, pour out your spirit heavily so that we can walk in a way that you're supposed to be, Father God. Hallelujah. And bless the pastor also. Bless her in a special way, Lord. Hallelujah. As she's teaching us a lot, help us to understand everything, Lord. Bless all the online students, offline students and everybody. Thank you for hearing our prayer. In Jesus' name we pray. Amen. Amen. Thank you. What is your name please? Because here it shows as Dipu. Yeah, my name is Dipu ma'am. Dipu? Okay. Thank you, Dipu. Thank you. Okay, so last week we were looking at chapter five. We looked at chapter three and chapter four. Basically, we're looking at the primary ways in which the Holy, you know, we receive guidance. What are the two primary ways we receive guidance from God? What are the two primary ways that we receive guidance from God? God's word and the Holy Spirit, ma'am. Yes. Thank you, Lucy. God's word and the Holy Spirit. Okay, so we looked at God's word, how God leads us and guides us through his word in chapter three and we are now looking at chapter four where we're looking at how the Holy Spirit guides us and leads us through the inner witness of the Holy Spirit. So, why is it called the inner witness? Because the Holy Spirit witnesses or we receive guidance leading, sorry, we receive guidance leading and direction in our spirit man, in our inner being. Okay, so we looked at common ways the Holy Spirit leads us and guides us, the common ways that the Holy Spirit bears witness in our spirit man and so we're going to look at eight different ways that the Holy Spirit bears witness in our inner person, in our inner man, in our spirit man. So, one way is through quickening of scripture. The second way is through the assurance within. The third one is the desire within and the fourth one is the knowing within. Okay, so we stopped at the fourth one which is knowing within. You know, the Holy Spirit reveals the plans, the purposes and the directions of God in our life and when we receive it in our spirit man we just know that it is from God. Okay, we just know it is from God. So, when like I was sharing when I was in 12th standard I was praying to God and asking him what he wants me to do next and you know God spoke to me and he said he wants me to go to full-time Bible college but at that time I did not know about the person and the work of the Holy Spirit. The church I came from never spoke about the third person, the Trinity Holy Spirit. So, I didn't know the person and the work of the Holy Spirit. I didn't know anything about the Holy Spirit but I just knew God would speak but when God spoke to me that one week I had, I just knew within that God was calling me for full-time ministry and there was this deep sense of assurance, the deep sense of confidence that yeah, this is God. No, this is not my own voice. This is not somebody else speaking to me but it is God.  Okay and we looked at the example of Moses right last week. Moses just knew in his heart that God had raised him up in the palace, given him the training so that he can be a leader to deliver his people out of Egypt. Okay, we look at the fifth common way that the Holy Spirit bears inner witness in our spirit man. The fifth one is a prompting. Now prompting is a little more stronger, little more forceful than knowing.  Okay, immediately your move to take some action. So, it's important that we may, we are sensitive to what the Holy Spirit is speaking to us and we also need to recognize what the Holy Spirit is prompting us to do. Sometimes the Holy Spirit will prompt you to take the phone and to call somebody unexpectedly. See and then when you call them they'll say, hey, thank you for calling because I was going through this, this, this, or you know, this happened, that happened. I don't know if it's happened with you, it's happened a couple of times with me. You know, last night I was going for my walk and I just sensed this deep prompting within, you know, it can be small things but deep prompting in it within to call up one of my friends who haven't called up for a long time. So, when I called her up she told me that, you know, yesterday was her 25th wedding anniversary and I missed it and she said, I was waiting for you to call me and pray and I'm saying, I'm so sorry, I didn't know and I think it was just God who was asleep, the Holy Spirit was leading me to call you. So, I called her up and I just prayed for her. So, I just sensed the prompting in my heart when I was going, I usually don't call but I just sensed the prompting in my heart to call her and I just called her even though it was late. So, sometimes the Holy Spirit prompts us to call somebody, to visit somebody, to write to somebody and you know, when you get this prompting there is an action, immediate action that you want to take. Okay, I'll give you another example. Just the last week I was going through some challenge in my life and I was so emotionally distressed. I didn't know, I couldn't pray, I couldn't think, I was just wanting, what should I do? What should I do? I just didn't get any solutions and my mind was so, you know, occupied and emotionally so distressed, I was not able to hear from God and I'm just praying, God show me what I need to do, what step I need to take. You know, this is really getting little difficult for me and suddenly when I was just, you know, I'm not hearing from God, I'm just sitting down and, you know, I just finished praying and suddenly this, the Holy Spirit put in my heart to, you know, WhatsApp this person who I haven't WhatsApp for years. The Holy Spirit is saying just tell this person and this person is a pastor so I messaged him and, you know, he messaged back later on the next day and what he said just one or two lines just gave me more clarity, guidance and help and the answer that I was looking for just two words but it was the guidance, it was the help, it just got so much of clarity, it removed all the doubts and the cloud that was just there and, you know, that uncertainty and now I know for sure what I need to do, what action I need to take. So it was a Holy Spirit who was just prompting me to send the text message to this pastor and he prayed and he just gave me the answer and it was just the right answer. So sometimes the Holy Spirit will urge you to do things like that, you know, you could take the action. There are some examples given here. Pastor has given a lot of examples for all of these points. You can read his life story and you can also, not now when I'm teaching but later on and then you can understand more about the ways that the Holy Spirit bears inner witness, in our spirit, man. Now the sixth thing is a steering within. We already looked at steering within when we were studying fulfilling God's purpose for our life. So I'm not going to dwell deep into this or explain deep because I've already explained it when we looked at the nine guideposts in fulfilling God's purpose for your life but just like to say that the steering within is more stronger than the prompting. It's more stronger than the prompting. The steering is so strong that you would need to take immediate action. We'll just look at one or two examples. In Ezra chapter one, verse one, we see that the Lord stirred up the spirit of Cyrus king of Persia and the Lord stirred up his spirit to allow the people of the Israelites, the Hebrews in Persia to go back to Jerusalem and to settle down in their own place. So here we see that God's stirring up the heart of this pagan king who does not know about God and God was bringing about his plans and purposes through this scheme. So the steering was so strong in his heart that immediately he fell into action and he allowed the Hebrew people to go back to Jerusalem. Another example is Haggai chapter one was 14. We see that God stirred up the hearts of the people to rebuild the temple. Now the people came back from captivity from Persia. They come back to Jerusalem. Now they are building their own homes. They're settling down. They're doing farming. They're comfortable but God's temple was in ruins. So we see that God stirred up their hearts to rebuild the temple and we see that the stirring was so strong that it called them all to action and they all went ahead and they build the temple and they finished completing the temple. So we see that the stirring sometimes God stirs us up for action and the stirring is so strong that we take immediate action. It's much more stronger than the prompting and the knowing within. Now the seventh one, the way the Holy Spirit bears inner witness in our spirit man is through the full knowledge within. So remember Jesus when he speaks about the Holy Spirit when he promises his disciples that the Holy Spirit will come. He says the Holy Spirit will show you things to come. He will show you things ahead of time what is going to happen. So the Holy Spirit reveals the mind and the plan and purposes of God what is going to happen much in advance.  But how do we know it? It's important for us to be sensitive to the Holy Spirit, to listen to the Holy Spirit and so that when he reveals to us we can take that into action. One example of full knowledge is in Luke chapter 2 where Simeon is a very old man and God promises him, is a full knowledge that he gives him promises him that he would not die till he sees the Messiah. So that is one of the four knowledges he receives that God promises him that he will see the Messiah and then he will die. And then on the day when Mary and Joseph bring baby Jesus as was accustomed to the temple when he was a baby, the Holy Spirit gives a full knowledge within to Simeon and tells him to go to the temple. So when he comes to the temple he sees the baby Jesus and he knows this is a Messiah he takes the baby and he blesses him. So here we see in the life of Simeon there is two four knowledges one that is where God tells him that you are not going to die till you see the Messiah that is one full knowledge which is extending for a period of time and also a second full knowledge which is immediate at that time where he says go into the temple and you will see the Messiah. So two full knowledges here we see. So sometimes the Holy Spirit will give you a full knowledge of what is going to happen in your life three years down the line, five years, 10 years, 15 years, 20 years. Why does he do it so that he can prepare you so that you are prepared mentally, emotionally to take on or to take hold of what God is calling you. And then there is the warning within the eighth one the last one is a Holy Spirit also bears witness in our spirit man to a warning. Now how can they have what is a warning sometimes we feel tightness you know when you're going to do something when you're going to start something when you're thinking of doing something when you're thinking of meeting someone thinking of going somewhere thinking of taking a trip or planning something you know personal there is a tightness you feel okay or sometimes you feel uneasiness sometimes you feel there is no peace and joy whenever you're thinking about this you want to do this you're planning to do this there is no peace and joy something is holding you back something is pulling you back. There is uneasiness. So all of this is the Holy Spirit is telling you that, hey, don't step into it. Don't do that. Don't go there. Don't speak with that person. Be careful. Okay. Because he's warning you of the challenges that are going to come in the future. Okay. So even in our spirit man, the Holy Spirit can warn us. Okay. Don't go there. Don't speak this. Don't say this. Don't send this message.  Okay. So these are eight ways that the Holy Spirit bears witness in our inner man. Okay. So we just looked at this morning. We looked at, you know, prompting within, stirring within the full knowledge within and also warning. And last week we looked at four of them. Okay. So let me give you an example of the warning within in Acts chapter 20 verses 22 and 23. We read that Paul was planning to go to Jerusalem. And even as he was planning to go to Jerusalem, he feels very bound in his spirit. Okay. And so he feels a tightening. He feels a binding in his spirit. And he knows that, you know, this is, this, this is a warning from the Holy Spirit that something bad is going to happen in Jerusalem. Something bad is awaiting, awaiting him there in Jerusalem. And so the Holy Spirit is warning him ahead of time so that he can prepare him self. Okay. So the Holy Spirit warns us we need to be, and the Holy Spirit guides us in eight different, these eight common ways that we saw. There can be more ways the Holy Spirit can guide us. Okay. But we just looked at eight of them common ways. But how do you know that the Holy Spirit is guiding you through these ways? You need to be sensitive to the Holy Spirit, which means you need to pray the Holy Spirit continually keep in connection with the Holy Spirit. So how do we train ourselves firstly spending much time in worship, prayer, and reading God's word, and also constantly communing with God, communing with the Holy Spirit. It could even be if you pray in tongues, you can keep on praying in tongues. Also, it's important for us to learn to be quiet and calm and still. The more quiet, calm and still we are, the more clearly we will be able to hear the Holy Spirit. Okay. Now, when the Holy Spirit bears, you know, witness in a spirit man, it's important for us to check. Okay. We can have a prompting within, we can have a stirring within a full knowledge, you know, we can receive all of these things.  So it's important when you're taking important decisions and you're waiting on the Holy Spirit, you need to confirm if you know this, if you're receiving from the Holy Spirit, receiving guidance through these eight common ways, you need to confirm. So how do you confirm? First of all, you need to confirm it with the scripture. Go back to the word of God, ask God to show you and confirm it through scripture. That's one way you need to do it. Second way is ensure that there is no emotional, natural, emotional involvement, which means sometimes, you know, if you're making a decision about your spouse or your children or your marriage, you're emotionally attached to that person. So whenever you're praying, the answer will come. Yes, yes, yes. Okay.  So you need to detach yourself from that. And you need to listen carefully to what God is speaking. So you need to have ask God to confirm through other ways. It can be through prophecy, it can be through scripture, it can be asking other people to pray, it can also be through the warning within whether you're receiving the peace and, you know, the joy of the Lord is there. Okay. Another way that we can ensure that or confirm it's the Holy Spirit speaking to us or bearing inner witness is through when the Holy Spirit leads us, it should always glorify Jesus Christ. It should always bring Jesus the glory and the honor. Okay. And also it should align itself with God's purpose for your life. Now, suppose you have a staring within or a prompting within or you have having a full knowledge that God wants to start a business. Okay. Which is a good thing. But what you need to do is you need to check. Okay. Have I got confirmations before that God wants me to start a business or it's just something on the spot. I get the stirring.  Okay, let me do business. So is it my own thoughts or is a full knowledge that has come before somebody has prophesied? God has spoken to me, you know, through scripture, he's spoken to me. So if you have those confirmations, you know that God is leading you towards that. Okay. So you need to see if it is aligning itself with the overall plan and purpose of God for your life. Also, there are some risks that are involved and you need to be very careful. You know, sometimes when you're making important decisions, you need to be careful about the risk that is involved. Okay.   Is anything wrong? Is there anything I can pray for? They say, no, everything is all right. Everything is going well in my life. So maybe that's not a big risk because just a phone call or you just go and visit somebody and you just find out that everything is fine with them. There is nothing really wrong.  So there's not much of a risk that is involved. But if you're taking major decisions in your life where risks can be very detrimental, which can be very serious in your life, then you need to wait and have different confirmations, wait for different checks, test things even before you jump into things. Okay. And the last one is you need to test the waters. That means if God is asking you to do something, you need to test. For example, if God is asking you to start a business, okay, you don't get excited and the next day don't go take a big loan and start a business. You pray about it and then you think what business you need to take or get into. And then you pray about it and then if God is leading you to start a business in a specific area, you go and speak to people in those areas who have a business, get to know things.  And maybe God is putting in your heart or you're thinking about three people who can join you for this business, your friends, and you pray about it. And then you go and speak to the first person and the first person says, okay, let me pray about it.  So you're, it's a confirmation. Okay.  So it's a confirmation.  It's important to always test and wait and receive multiple confirmations before you get into things that God wants you to do or where God is leading you and guiding you. Okay. So this is chapter four, which is talking about the inner witness of the Holy Spirit. Anyone has any questions? Any questions? Yes. Can you please take the mic? It's not from the book, but it's about Holy Spirit. It says whoever speaks a word against the Son of Man will be forgiven, but whoever speaks against the Holy Spirit will not be forgiven. So I want explanation about this. Okay. Whoever blasphemies against the Holy Spirit because they're actually here in this context, they're actually talking, they're going against the very plan and the purposes of God. Okay. So God's in God's plan and purpose, he has sent the Holy Spirit to, for the Holy Spirit, the third personality to fulfill or to do what he has purpose and vision. So when we are blaspheming the Holy Spirit, we're actually going against a very redemptive plan and the purposes or the very, we're going against a very plan and thoughts and the purposes of God, what he has already foreordained, what he has already planned. So it's going, totally going against God. So when we blaspheme against the Holy Spirit, we are actually going against a very redemptive plan and the purposes of God and that's why it says it is something that God will not forgive us for. So is it for believers or for unbelievers?  So if we blaspheme against the Holy Spirit, yes. If we blaspheme against the Holy Spirit, but after some years, he just confess and comes back to God. So will he sin before given? What do you think? I'm confused about that. What do you think is the nature of God? What is the nature of God? Whenever you're confused about anything about God, you need to go back to the nature of God. So what is the nature of God? He forgives. Yes, he forgives sin. So he's gracious, compassionate, merciful and forgiving and he forgives us. So when you go back, will he forgive us? Yes. Any other questions? Any questions? Sorry, camera's blurred. Sorry. Yeah. Okay. Anyone else has any questions? Can we survive without problems in our lives? Can we survive without problems in our life? Our life is filled with problems. Yes. We are struggling in our life. Yes. Yes, we can survive. Why not? Because God has given us everything that we need for life and godliness. He's given us the weapons that we need for our warfare to fight against everything that the enemy is coming and doing against us. He's given us the word of God that we can speak, declare. There are 3,000 promises in God's word. His promises are yes and no amen. And when we speak those promises, we see situations change. We see mountains move, giants come down.  So why not? And God has won the victory on the cross over everything. He shares the victory with us. Hebrew says he's a captain of our salvation. Hebrew chapter 2 or chapter 3. He's a captain of our salvation. Then why not?  That's not what he died for us, right? He took away everything on the cross that we can live the Zoë life, the God kind of life. And we've been given the fullness of the God has been given to us. We're complete in Christ Jesus. So it's important for you to know, it's important for you to know who you are in Christ. Once you know who you are in Christ, what authority you have been given. And Hebrews Romans chapter 6 says that we have, what is our identification? Our identification is that we are our spiritual identification or the spiritual truth is that we have been crucified with Christ. We have been buried. We have been resurrected. We have been, we ascended with Christ and receded again at the right hand of God, the Father. So when we're seated at the right hand of the Father in the spiritual sense, what does it mean that we have been given all authority and power? And we can speak to those challenges and those challenges have to move. So you need to know what authority and power you have been given and received. And then you can walk in victory and not in defeat. Okay. Any other questions? Yes. Can you please pass the mic to him? This side, that side, that side. You can just pass it. Yes. How to keep aside our natural emotion? How to keep aside your natural emotions? Yes. So what you need to do is you need to, you know, when you're going through a problem in a situation, you're very stressed, your emotions are, you know, like a roller coaster, you're not able to think right, you're not able to concentrate. So you need to give yourself some time. In that time, you need to continue keep praying in the spirit, praying to God, asking God to help you to control your emotions to come to a place where you can hear him and receive from him. And you need to quiet in yourself. Make your, come to a place where you learn to quiet in yourself so that you can learn from the Holy Spirit.  I'm just going to, you know, put it aside. I'm going to forgive that person, deal with those things, letting go of my anger, deal with the unforgiveness, the jealousy, the hate, whatever, ask God to help you in the process of feeling your emotions. Then when you come to that place, you know, then you'll be able to listen clearly from God. So it can take some time, but it'll, you know, when you are in a place where you're settled and your mind is more at rest and, and at peace, then you can hear the Holy Spirit. Yes. But don't keep thinking in your own mind. What should I do? What should I do? And keep on mulling over it and more anger, more stress, more jealousy, more hatred. You need to come to a place where that is weaned off, where you are dealing with it, asking God to help you, forgive, get rid of those things. And then, you know, your natural emotions will set aside where you can hear the Holy Spirit. Good question. Anyone else has any questions? Okay, ma'am. Sometimes I'll be able to hear the voice of the Holy Spirit. So continuously, so even when I'm working or alone or praying, every time I'll be able to hear it. But sometimes, like, I was not able to hear the voice of the Holy Spirit for two or three days, it will be like complete silence. And I was able, after that, I will be able to hear it. So is there any particular reason or is that my thinking is like that Holy Spirit is not talking to me like that? See, Holy Spirit is not just when you hear the voice of the Holy Spirit, the Holy Spirit can speak to you in different ways, like a warning, a peace, joy, happiness, can speak to you through scripture, can speak to you through sermons, through a worship song. You can just experience the presence of the Holy Spirit. You can just experience the empowering of the Holy Spirit. So the different ways that the Holy Spirit speaks, not just the voice of the Holy Spirit that you hear.  So, you are not able to hear the Holy Spirit. Sometimes the Holy Spirit also does not speak because the Holy Spirit wants you to just go along with what He has given you last, okay, or what He's spoken to you last, go with it. So you're praying about something, the Holy Spirit feels that there's no change in that area. You are, suppose I'm saying, God, I don't want to be in this workplace. I need to leave this workplace. I need something else. But the Holy Spirit is not speaking to you, which means the Holy Spirit is saying, continue in this workplace till I speak to you, lead you and show you, you know, whether you need to move out from here. So when you're not hearing sometimes when the Holy Spirit is also, just go with what the Holy Spirit is also telling you to go with or He's not, you know, maybe there's nothing that you need to hear now. Or He's just speaking to you from the Word of God, so different ways the Holy Spirit speaks. So you need to also discern different ways that the Holy Spirit is speaking to you, not just through your, through the voice of the Holy Spirit. Did that help Jennifer? How to be sensitive to the Holy Spirit? I already, I mentioned it, get through it. I said, we need to spend good time in prayer, in worship, in reading God's Word, praying in the Spirit at all times, communing with the Holy Spirit. We speak to the Father, Son, but we don't speak to the Holy Spirit.  Okay. Any more questions? I hope that helped get through it. Any other questions? Thank you, Sister. Okay. Yes, Anusha. How can we understand the confirmation about the business of something? Who can we understand? It is the confirmation from the Holy Spirit of God. Okay, then we are prompting, there will be a stirring within for you to take an action, and also you can ask God to show you from His Word. He can speak to His Word. His Word has answers for any and every situation, even for business, even for the smallest thing.  Also the Holy, you can ask the Holy Spirit to, suppose it's from business, you can ask the Holy Spirit to guide you and lead you and show you what you need to do, which area, and then, you know, the Holy Spirit will show you which area you need to start the business. He will show you who to contact, and when you go, you will find favor. You will just find open doors, you know, and you will just sense God just moving. So you need to test the waters, like I gave you an example of how to test waters for business, you know, you need to test your, maybe you put in for a loan, the bank gives you the loan, everything is falling in place. Sometimes yes, their things might not go smoothly, but in respect of that, you will have the, you know, the warning within, which is you'll have peace and joy, or if you have a lot of anxiety, there is, there's stress, things are not going properly, there's a lot of confusion, there's a lot of tightness, there's feeling of binding, it's a warning that the Holy Spirit is saying don't venture into this.  It can also come to a prophetic word or somebody's praying for you. You can ask people to pray for you and ask God to lead them, you know, to show you what you need to do or whether it is a yes or a no. You can also wait on the Holy Spirit and ask him, can you hear the audible voice of the Holy Spirit? So I mean, the voice of the Holy Spirit is speaking to you. So all of these can be different confirmations. Thank you, Pastor. Yeah. Yes, sure. It's about the particular situation when we got the confirmation and we apply all these things that we have. But, and we are praying for that thing for a long time, but still we did not find the open doors. So we can move forward. So on that time, what we're supposed to do? So don't find open doors. It might be, it's not the Kairos moment. There's God works in Kronos moments, Kronos time and Kairos time. Kronos time is a chronological time where God is preparing you. Maybe God feels this is not the right time for you to get into it because if you get into it, you're not mature enough.  You don't have the expertise. You don't have the abilities. And maybe he foresees that this is not the right opportune time for you to start.  And when you launch his out, he knows, you know, the work would be excellent because you are skilled enough, you're prepared enough, competent enough to do what he has asked you to do. Another reason can also be maybe you are sensing that it is God is asking you to do. If it's close those, it means God is, it's not what God is asking you to do. It's your own desire. That can also be another reason. Any other questions? Yes. Can you pass it to him, please? Somebody's for someone and he's saying that you are going to become a good teacher. So now he's an interweather standard. So how he will get the confirmation? How will he get the confirmation? He has to go back to the scripture, read the word, ask God to speak to him to scripture, ask the Holy Spirit to bear inner witness through one of these common ways, prompting, steering, foreknowledge, whatever, and also sense what the Holy Spirit is saying. You will get confused about his future studies. Actually, if he will remain towards the standard, he will do his study or even go to the ministry field. So it doesn't mean that because somebody prophesied that he's going to be a preacher, the very next moment he has to start preaching. No. See, we see examples in, we saw the examples, right? Preparation process in fulfilling God's purpose for your life. Even for Jesus, it took 30 years for the preparation process. In the sense of preparation, the Kairos moment was 30 years. That was because if he had to be a rabbi, people had to, the 30 years was the right time whenever considered as a rabbi. Okay, not before that. So he had to fall in line with the Jewish cultures and tradition. So it doesn't mean that because somebody prophesied, hey, you're going to start a business, tomorrow you go and start or you're going to be a preacher, tomorrow you start preaching. No. God told me in 12 standard, I wanted to come to full-time ministry. The next day I was not in full-time ministry. I started full-time ministry almost seven years after he had told me.   He opened the door for Bible college. So there was a sensing, there was a leading, there was a direction, there was a move and how God provided, he took care. I studied for six years and then I stepped into ministry. Yeah, so God reveals plans for knowledge. That's the for knowledge within five years, 10 years. So why does God give us the Holy Spirit, gives us for knowledge so that we can prepare for that, prepare mentally, spiritually, emotionally in every way we prepare because for me, I needed that time because I was not ready to go to full-time ministry. That was not what I was thinking about, but God called me. So I need to go to the preparation process. Did that help? Okay. Lucy says, when two believers pray over certain things to go ahead and one gets confirmation and the other doesn't, how do we act upon it? We need to wait till the other person, you know, receives the confirmation. We're going to talk about that in a bit so you will understand more better Lucy.  I'll just explain that. Yes. God's for knowledge about us? About our what? Sorry, deaths? Your deaths. Why not? There was a word of wisdom and that a preacher went to meet another preacher. He had built a new church and all of those things. The gifts of the Holy Spirit was working in him. So this preacher met him and he showed him all his new church and everything. And so this preacher is very happy. He came back.  And the way he is, you know, living his lifestyle, the way he's eating is not a healthy way.  So the, the preacher goes back, tells him the word of wisdom and knowledge that he received. The preacher did not listen to him and he died in a few years time. So yes, God can give us for knowledge. Yeah. Okay. We move on to chapter five, the voice of the Holy Spirit. Okay.  It's much more stronger than the inner witness of the Holy Spirit. Now we looked at the inner witness of the Holy Spirit. Don't confuse that. Okay. There's the inner witness of the Holy Spirit and there is also the voice of the Holy Spirit. The inner, the voice of the Holy Spirit comes more stronger, louder, clearer in many cases than the inner witness of the Holy Spirit. Okay. And the voice of the Holy Spirit is often or not always, you know, instructive and directive. So, you know, you can hear the voice to the inner voice of the Holy Spirit. The Holy Spirit speaks to us to the inner voice, the audible voice, the voice of the spirit in prophecy and collective witness of the Holy Spirit's leading. Okay. So, there is an inner witness of the Holy Spirit, which we saw eight different ways, but there are also the way the Holy Spirit speaks to us and there are these three ways of the Holy Spirit speaks to us. The inner voice, the audible voice, the voice of the Holy Spirit and the Holy Spirit also speaks collectively.  Okay. So, let's look at what is the inner voice. Now, the inner voice, the Holy Spirit is when the Holy Spirit is directing us, the Holy Spirit is speaking to us or making statements, but there is no audible voice. Okay. Now, when I am, I'm communicating something to you, right? I'm teaching you something, but then you can hear my audible voice. But the inner voice of the Holy Spirit is when you can hear the Holy Spirit speaking, but there is no voice. There is no Shelly, no, you have to do this or, you know, it's no audible voice.  He's directing you. He is leading you, but there is no audible voice. There is no sound. Okay. But the Holy Spirit is communicating information in your spirit, man. There is clear direction, clear statements, but there is no voice. So what is an example? An example is, you know, when I was, I told you, when I was in 12 standard, I used to study late in the night and I put out the light and I used to pray. And then the Holy Spirit, when I was praying God, what do you want me to do next? The Holy Spirit is calling me into full-time ministry. Now, I didn't hear the audible voice of the Holy Spirit saying, you have to go to college. There's not a soft voice, a calm voice, a soothing voice, or a loud voice, a deep voice, nothing. It was directions. It was guidance. It was statements that came, sentences that came, but I knew it was God speaking to me. So Holy Spirit speaking to me. And I could not just hear that voice coming, but I knew in my inner spirit that it is the Holy Spirit speaking to me. Okay. So that is the inner voice of the Holy Spirit. And there is the audible voice of the Holy Spirit, which we read in scripture. The audible voice of Holy Spirit was when Samuel, you remember Samuel when he was small boy, God calls him Samuel, Samuel. Okay. So that is the audible voice of Holy Spirit. What the prophets here heard was also the audible voice of the Holy Spirit. Okay. But the audible voice of the Holy Spirit is very rare. It's a very rare experience. Not many people have heard the audible voice of the Holy Spirit, but they hear the inner voice of the Holy Spirit. Okay. And there is also a voice. The third one is you can hear the voice of Holy Spirit in prophecy. I'm not going to explain that here because there is a complete chapter that we will be studying in just the next two in two chapters will be studying about prophecy. So then we will understand how the Holy Spirit speaks to us in to the audible voice of prophecy. Okay. We'll stop here. We'll go for a break and then we'll come back and continue.


In this video, we're going to be looking at determining the neutral current in an unbalanced system. If you go back and watch the video on Y configuration or star configuration determining neutral current in a balanced system, you see that the currents in a neutral always end up being zero amps. We prove that through vector algebra. The same thing holds true when we are discussing current in an unbalanced system. We still have to use that vector algebra and I'll prove it to you. Let's take a look. First things first, let's get our Y system or our delta system set up. So we've got our Y system. I've got three different phases and then I have a neutral, that star point we call it. That's the genius of the Y system. Then we're going to label them. We've got A phase, B phase, C phase and as I said the neutral. Next up, what we do is we get our instantaneous polarities figured out. So again, as the purists will no doubt rail against me, I understand that they're going to be different at different points. I've got negative positive, negative positive, negative positive and it looks like they're all happening at the exact same time. I understand that in a three phase system, each line is going to be 120 degrees at a phase. So they will not be happening at the same time, but the math still works. So let's not get too hung up on that. So let's take a look what we've got here. Let's give some currents to these phases. So I'm just picking these out of the air. I've got 12 amps, I've got 6 amps going through this one, I've got 20 amps going through this one. Again just as with single phase, we know that the neutral carries the unbalanced current. Well these are not balanced. It's not a balanced system. I've got 12 amps here, 6 amps here, 20 amps here, which this is more realistic. You're not going to see very many balanced three phase systems if ever, it's more of a theoretical thing. You will, however, definitely see an unbalanced system. So this is very practical. First thing I do, as you know, I like to get my X, Y chart drawn out there. And again because these are all happening at different times, we have to figure out what their X and their Y coordinates are because we cannot just add 6 to 12 because they're heading in different directions. Then I would tell you to go watch the videos on vector addition if you don't understand what we're talking about at this point. First things first, let's start with B phase because it's all X no Y. So I come in here, I'm going to go negative 6 times the cos of 0 degrees gives me negative 6. Negative 6 times the sine of 0 degrees gives me 0. So that's breaking our 6 amps at 0 degrees into the X and Y coordinate. Then we come in on this phase here and what we're going to do is we're going to go negative 12. You see how I'm entering here and I hit the negative first? Negative 12 times the cos of 120 degrees because we are 120 degrees out of phase gives me 6 amps, or not 6 amps, just gives me 6. And then negative 12 times the sine of 120 degrees gives me negative 10.4. One last but not least, the 20 amps, again it's a negative because I'm hitting that negative first so negative 20 times the cos of 240 degrees gives me 10 and negative 20 times the sine of 240 degrees gives me 17.3. So now what I can do is I can add all these up. I got negative 6 plus 6 is 0 plus 10 equals 10 and 0 plus negative 10.4 gives me negative 10.4 plus 17.3 gives me 6.9. This is my rectangular vector and I've got to figure out, break it into polar form. So I use Pythagoras' theorem, 10 squared plus 6.9 squared equals 12.1 squared. That's a 1 not a 7, 12.1 amps. That's what's going to be on my neutral. With all these different currents coming in here to balance it out the neutral needs to carry 12.1 amps. So in an unbalanced Y circuit you use the vector algebra to calculate your neutral current. Just like we used the vector algebra to prove that in a balanced circuit the neutral current will be 0.


This is stock number 20J129A. We are here at Summit Automotive in Fond du Lac, Wisconsin. You're new and used Chrysler and car headquarters. Today we are checking out this super clean 2016 Chrysler 200 Limited. This vehicle has the 2.4 liter multi-air motor. It has been fully safety and inspected by our service shop has a fresh oil and filter change. All the fluids have been checked and topped off and this car is 100% ready to go. Black clear coat is the color we shoot all of our videos in 1080p 60 frames per second so if you have HD capabilities on your computer tablet or smartphone device turn them on right now because it is definitely your best way to check out the quality and condition of the vehicle before seeing it in person. And if you'd like to check out all the photos on this car and the upper right hand part of your screen is a link right to our website click that and check us out there. It comes with the factory alloy rims. General Ultimax tires these are 215 55R 17s and they have a really good amount of tread left I'd say 60 to 70% of the tread left on those tires. Front fender absolutely perfect no dents or dings on that. It does come with the projector lamp headlamps the LED running lights and that front bumper is in excellent condition. I didn't see any dents or dings or cracks on it and the hood on this car is in excellent shape as well. Passenger side front fender is in nice condition too and the passenger side rim pretty nice shape as well. As you go down this side of the car take note of how clean the body is how reflective and mirror like that paint is we take these HD videos so if you are far away or even if you're close by and just cannot make the trip down you can still see the car hear the car and have confidence in the vehicle that you're looking at before even get here so that when you do get here there's absolutely no surprises. Roof is in nice shape and that is why we offer the Summit Auto Fastpass option in the upper right hand part of your screen a link right to our website where you can apply for financing get pre-approved see a payment quote even appraise the trade all from the comfort of your own home. Back rim is in nice shape four-wheel disc brakes on this car and the back tires actually look like they have maybe a little bit more tread than the front tires I'd say 70 to 80% on the rear tires there rear bumper is in nice shape no major dents or cracks and the trunk is in nice shape as well. Lots of room in the trunk area those seats do fall down for extra storage and this one does come with a spare tire you got the LED running lights in the back and as you go down this side just as clean as that passenger side no dents or dings on that rear quarter and this back rim pretty nice condition as well a couple little scuffs but it's pretty common on these cars. Down the driver's side doors all look really good it does have the enter and go system inside the limited package gives you the black cloth interior no rips no tears very very clean driver's seat height adjuster factory floor mats auto headlamps power windows power locks and power mirrors. As we hop inside here you can see that this one has 92,937 miles you get the nice instrument cluster with the blue hue on it steering wheel is in nice shape cruise controls on the right Bluetooth and information center controls on the left and you do get audio controls on the back has the five inch touchscreen radio and FM and Bluetooth capabilities also this is where your backup camera shows up. Start it up here and show you and this one also has the nine speed automatic transmission your climate controls are right there as well I can tell you that the air conditioning is working really well in this car there's your touchscreen this is also where your backup camera shows up. You have that enter and go system with the keyless entry fob there that's a nice shape and the passenger side floor mat and seat are in really nice condition as well no rips or tears in that headliner looks really good and you do get map blades up there. We'll take a quick look at the back seats and then we'll check out under the hood the back seats are just as clean as the front seats no rips no tears back here it does have the latch child safety system for all your child car seat needs factory floor mats back here carpeting looks really good and these seats do fold down for extra storage there is a pass through there to get to the trunk area and last but not least you do get the child safety locks on the back doors all the bottoms of the doors look really good as well. We'll take a quick look under the hood I would personally like to thank you for checking out the video today and hopefully from this HD video you will have been able to tell just how clean this car is all the way around under the hood we have the 2.4 liter multi-air motor. This one pumps out 180 horsepower engine base very clean runs very smooth this car has been fully safety then inspected by our service shop has a fresh oil and filter change all the fluids have been checked and topped off car has been gone through mechanically 100% and is 100% ready to go and to see more pictures of this beautiful car go to www.summitauto.com full pictures and descriptions of every single vehicle from two locations all at summitauto.com and if you'd like to check out more HD videos you can go to youtube.com slash summit auto remember to like subscribe and share on this video and all the videos that you see there in fact in a second you will see a link to subscribe to our YouTube channel on your left a link to more Chrysler 200 car videos like this one on your right if you have not been to our website on the bottom link to this vehicle on our website click those check us out and we really look forward to help you with this super clean 2016 Chrysler 200 limited in black clear code thanks again