Hi, I'm Chris Hodge from the OpenStack Foundation, and I'm excited to share with you Mitaka, the 13th release of OpenStack. OpenStack is a cloud operating system that provides compute, networking, and storage to host all of your applications and services on top of standard hardware.  In this video, we're going to give you a brief tour of these services and describe some of the new features that you can take advantage of in this release. We begin by logging into the OpenStack dashboard and uploading a Linux image. Once the machine is uploaded, we configure security access rules for SSH, a secure key pair for passwordless login, and an external IP address to attach an instance to. With our security and access rules set up, it's time to launch an instance. With the Mitaka release, the OpenStack dashboard has been refined with a new focus on intuitive workflows. You can work quickly through defining the source image to use, the flavor of the instance, attached networks, and security features. It even simplifies the automatic creation and attachment of block storage volumes to new instances, and the assignment of public IP addresses. Switching over to the curvature interface, we get a dynamic and easy to use visual representation of all of our virtualized compute, storage, and networking resources. One project we're excited about sharing and think you're really going to like is the OpenStack client. The OpenStack client is an all-in-one replacement for the variety of clients that ship with the individual projects. Its user-centered design is influenced by a human interface guideline with core principles of simplicity, consistency, and transparency. In this example, we launch another instance with the OpenStack client, noting its simple imperative structure and clear configuration options. The OpenStack client is a powerful interface for creating, reading, updating, and deleting virtualized resources. It is quickly becoming the preferred replacement for all the other clients, with frequent additions of new features and a plugin model that allows for extensibility to any new project under the OpenStack Big Tent. To finish, we'll demonstrate the ease with which you can automate complex systems using heat, the OpenStack orchestration service. We start by writing a stack template that defines all of the resources we want heat to manage the lifecycle of. In this example, they include a machine image, two networks with subnets and routers, a web server, a database server with attached storage, and two worker nodes. With template in hand, it takes only one command using the OpenStack client to launch the stack, and it's easy to check on its status. Switching back to the curvature interface in the dashboard, we can see the output of this command, a complex and reproducible OpenStack-based application. In the Metaka release, heat now handles dependencies asynchronously, making it much faster at updating and maintaining the resources it manages. Its developers are constantly adding new resources to its ever-growing catalog, and heat is becoming an indispensable service for defining and maintaining project infrastructure. In the OpenStack Metaka release, you can expect a refined user experience, streamlined management, and improved scalability for performance and stability on larger deployments. Thanks for watching, and have a good time with OpenStack.


Every single week, Lydia is a power of engineering to find things on digikey.com, thanks Digikey. Lydia, what is a great search this week? Okay, so this week, I'm going to get to it. We're doing an ultra-slim microSD card, so let's go to the computer so I can show this thing again. So I want a microSD card slot that is not wide like this, but is because this is too wide to fit between these pads and it interferes. I need something that's less than 12 millimeters wide. So let's go to the overhead and I'll show how wide these things are to be wide. Okay, so this is 14 millimeters wide, which is, like I said, way too wide. Now ironically, on the Pico W or the Pico, this would fit because I'm not using these, don't use SMT headers, use through-haul headers, but on my accessories, I want to use SMT headers, so the pads come out to the side. And so that won't fit, and this barely fits even here. So one thing I did think I was like, oh, you know, I looked at the teensy, which I had one hanging around, and this one actually is like almost exactly 12 millimeters. So I knew that this was possible to find something that would fit perfectly in between those pads. I just need to use my didgeridoo search capabilities. So one thing to just note for is that this is not a push-pull. What you get when you get that extra width is there's the spring here, and the spring is what lets you do the push-push ability to, you know, you push it in.  And then this is push and pull type. So, you know, there's trade-offs. You know, the Raspberry Pi computers also changed. They were push-push, and then I think, you know, that was the spring can break. It's not really meant for, you know, infinite insertion removals. This one, you know, it's not as like elegant because you have to yank it, but it's skinnier and you don't have the spring that can break. So let's go to my computer. And so we did actually cover the SD card holder in a previous great search. You can see it here, like this is this part. I use it everywhere, and it's wonderful, and it's great. But again, it's a little bit too wide. So what I want to do is I want to find an alternative, something that does very similar stuff. And you can see this lovely rendering. There's lots of these in stock, which is great. I want something that's, again, a little skinnier. And one thing to note is that the size is not documented. It's not a searchable element, which happens sometimes, especially for some connectors. You don't get dimensions as a searchable thing. So what you have to do is just look at them and then check the datasheet and just read each one until you find the one.  You find a board that has the part and you're like, okay, I know that this exists. I just need something that looks like that. So let's look for a active microSD holder. And let's view similar. So already we got a couple options. So this is the hinge type. These are very slim, but I don't, this is not a good board for it because I want people to be able to remove the card from the side. These hinge ones are really good when you have the SD card in the middle of your PCB.  Whereas the SD card, you know, the card holders I'm looking at, they need to be on the edge because you can, you know, there's nothing in the way you can pull the card out. So I do want to remove hinged lids. So I'm going to select everything but hinged and then apply that to get rid of like the 12 that don't have it. Okay, so now we've got a couple options. So, you know, the first one, first one we've got here is, you know, what I've got already, it's got the spring. This one, I've actually seen this before. I saw this on a, they're ultra, ultra tiny and like just like the ends go in. It's like, it's kind of weird. One thing that is nice is it's high up above the board and so a lot of people use this. You can't put it in the middle of the board because often it'll float above any like resistors or maybe slim capacitors or even a chip. And because it's not, the SD card doesn't go up against the PCB. It's actually kind of levitated. The only thing that's weird about this is I don't like that the SD is like it's really exposed because only the contacts are connected. So I've seen this board used as this connector. It is by far like the most compact, you know, simplest SD card holder but there's no mechanical strength to it in my opinion. So the next one is, we've got these Amphenol parts. So this one has a spring. So I think we can't use this one. This one looks like it's very similar to this lady. So let's look over here in the specs. So this one, let's scroll down. We can see the dimensionals. They don't have dimensional specifications. Why would they add that? This must be an incomplete data sheet. Okay, well, that's not very helpful. Let's try this one. Okay, this is much better. So I love it when the data sheets are scans of like documents. So this one, I think this is actually the same part that's on the teensy because this is 11.95 millimeters. So it's like it's again very, very narrow. So this is like the one I think I'm going to go with. However, there's a couple other possible options. Let's look at this one. Maybe this one has. Yeah, this one has. Also, this is 11.95 millimeters. One thing I do like is it has a switch on it. I like my SD card. Most SD card slots these days do have a switch. It lets you know that the card is inserted or removed. So before you perform any SD card communication, you can check to make sure that the card is in place. You don't end up hanging on like waiting for data to respond. Nothing. I don't think this really works. But like if you are writing data to an SD card, you can kind of detect right when it's about to be removed. And like you might be able to flush the data really quickly. Although I don't know how fast you can do that before the contacts lose connection. But these are all really good options. So let me just look for ones that are in stock. And then let me look for pricing. Let me make sure the pricing at 5,000 pieces good. So yeah, these are cheaper for sure. And you can see even the thickness of the plastic at the bottom there that levitates it. And there's a couple options of these super skinny ones. This one's very cheap. This one has that spring. So it's going to be too wide. This is a flip top actually, which shouldn't have made it into the search, but it did. So the one that is the least expensive, it's basically a dollar at the 5,000 piece mark is this Amphenol. So this is what I'm going to probably go with. It looks like the part on the teensy doesn't say Amphenol. So I think this is a generic layout component. Probably Amphenol first came out with it. And then other people made variations that are very similar. I'm going to try this. I think this is a pretty standard part. So I should be able to get. I don't like to get connectors that are only available for one supplier. So I'm going to first make sure that this pin out and pad, like the push pull SD card is available for multiple places. And then I'll try it out. But the good news is that, you know, once I lay out the pins, it'll work with all the code exactly the same because the contacts are exactly the same. So this is my, my great search pick. That's a great search.


Hey, very brief personal project. This is a M-SATA drive. It is a solid-state drive. You can get these. This is a 256 gigabyte drive. I got it for maybe around $40 on eBay. I'm gonna install it in my ThinkPad X220. So I'll just show you the process. It's very very simple. I've never installed an M-SATA drive, but it's very very easy. The, you know, I've opened my computer a million times. The plug-ins right there. Let's go ahead and do it. Alright, so obviously most important is that you have your laptop turned off, and you want to unlock your battery and release it. You might have one of the smaller, what, six-volt batteries? I have a bigger nine-volt battery. So next you'll notice, if you actually look very closely on ThinkPad models, they have these little symbols right here, okay? Like one is a keyboard and one is sort of a, I don't know, I guess sort of a bezel kind of thing. We are going to want to unscrew all of the screws with those little markers on them, because the ones with the keyboard will allow us to unscrew the keyboard. The ones with the other thing will allow us to unscrew. We basically want to take all the top off the computer. So I'm going to unscrew all of these pretty quickly. You don't have to unscrew these that are unmarked. That is not necessary. Just the ones that have, you don't even need to unscrew that. That's the RAM cover. You don't need to remove this. But all the other ones like that, like that, like that, etc, etc, you need to get rid of. So I'll do that in just one second. All right, so I've removed my screws. I have six of them. You might have more. There are some screws that I don't know. I didn't have anything in there. By the way, a brief recommendation. This is what I have for unscrewing computer parts and other stuff. This little, I don't know, like, I guess a little set. I recommend getting this, something like this. If you are, I use it to repair computers. I use it to, I used to screw in my sunglasses and other things. This is very nice to have. Of course, you'll need a Phillips head for all of these in case it isn't obvious. But anyway, once you have unscrewed your computer, you're going to go around to the front. And this is the tricky part because I'm going to try and do it with one hand. But you are going to want to sort of push forward on the, I'm not gonna, I'm not gonna do this with one hand. Give me a second. Okay, yeah.  So I'm like pushing that way. And the keyboard will start to come up. It is attached by this thing. You can just sort of peel it off and it will become disconnected. Additionally, you might notice there's this blue thingy right here. This one works a little different. You can't just peel it off instead.  You might need a credit card to get to it. I just got lucky this time.  Without putting, don't put any pressure on it. If you need to put pressure on it, you're probably doing it wrong. And then this part will just sort of snap out. Okay, so let's look, let's look at what's inside of here. Just in case you don't know. So this, of course, is going to be your hard drive over here. That's not, you don't access it this way. You usually just unscrew one screw here. That's how you get to your hard drive. You have a bunch of different things. So you're, you know, your fans over here. But the thing that we care about is down here. So this thing right here, that's your Wi-Fi card. And its antenna is hooked up. So to this little black cord and gray cord, it might actually be different on your computer. But on my machine there's this blank area right here. This is where we're gonna put the M-SATA drive. Now there's a chance that you already have some M-SATA thing already hooked up in here. In which case it's going to be screwed in here. So you're going to want to take your screwdriver, unscrew it, and it will basically pop open and you can just pull it out. Okay, if that's not clear what I mean by that, we're gonna just about, we're gonna do basically the reverse right now. Okay, so I'm gonna take my M-SATA drive. All right, and I'm going to, I'm gonna move these wires out of the way. I'm not gonna try and unplug them or anything. Now notice, of course, you have these two openings where the screws go. And this is where it actually plugs in. And it is gonna plug in this way sort of to the left. Now how these drives plug in is notice how it's sticking out, okay? That is how they properly plug in. You want to have them sticking out, make sure there's nothing behind it. I'm gonna move this Wi-Fi cord that's sort of under it. Okay, I might have to actually move this a lot around. But once it is deep in there, nice and nice and stable, you just push it down, okay? Now the next thing is I actually need to find a screw to go in here because there's not a screw here. I didn't unscrew something. So I'm gonna look through my little screw. I don't know my little repository. I have a whole, an old film case of them.  I'll come back in a second with the screw. Okay, so now I found a little screw that fit from my old little film canister.  This is what they used to look like. Back in the 90s, we used to have these. Early 90s too, you know? Anyway, so you want to find a little screw that fits as I have one here, a little white one. See, the other thing about screws is, I'm gonna screw this in. Mind you, that's what I'm doing. Okay, so you sort of want to hold it down while you're screwing. It is very hard to do this with one hand. I'm gonna have to do it down here. I was gonna say one thing about screws when it comes to computers is if you want an infinite supply of screws, just keep opening your computer and closing it back up. Because every time I open my computer and unscrew everything and then screw it back in, I always end up with extra screws. I don't know. I guess there are just screws I'm missing, but it doesn't really matter, you know? I don't know. As long as it's not wobbling and stuff, it doesn't matter. So anyway, now we have that in place. It should be if it is nice and deep. Actually, I need to screw this just a little more. Okay, because I didn't, I gotta pay attention, okay? But once it is nice and deep in there, I don't know how that's, is that deep in there? I think it is. I think my screw is just not. I probably should have gotten a slightly bigger one. Okay, that's a little better. Okay, it's just wobbling because it's a little, well, it's not actually wobbling. It just sounds like it is. Anyway, okay, so I'm gonna put this back on. Make sure everything, now to put this little blue thingy back on, let me actually put this more in your face.  There are probably technical words for all of this stuff, but who cares? Who cares? I'm gonna get that in there, okay? And once it's in there, just put, you know, I don't know, clip down the black thing on top of it so it doesn't move. And then the keyboard, again, you do not have to do any clipping and stuff. You just sort of insert this into the place here. Don't drop it, hold on. Okay, again, so you just take this little thing, okay, and it is going to plug in nicely. You will be able to feel when it fits in because it'll be a perfect fit and you won't be able to easily yank it out. Of course, you don't want to yank this out. You don't want to break the ribbon. And then to put this back in, you want to put the far side in first and then sort of push it that way and then sort of slide it back and everything will click. And if everything, you know, or at least things will 95% click and the rest will click when you put those screws in. So I have a couple parts, you know, one thing, one wear and tear thing, you're going to have a little bit of movement on your thing if you don't have your screws in. But everything should be plugged in. Now I'm going to screw everything back. All right, I think all the screws I originally had in there are now in there and I am going to plug this battery back in, lock it back, and I'm going to boot up and I'm going to see if my drive is detected. Okay. All right, so I've logged in and I have LSBLCade to list my block devices, SDA1. That is my classical hard drive. It's around a terabyte. And now we have SDB. So SDB is my new M-SATA drive. There it is. So as to what to do now, you want to partition your drive, you want to do whatever with it. But that can be operating system dependent and some other stuff. So I'm going to end this video here because that is the end of our hardware portion. I might be, I might be actually moving over my operating system from SDA to our M-SATA drive, I should say, and encrypting some stuff. So that might be in another video. But anyway, that's it. That's how you install an M-SATA drive on an X220 ThinkPad.


In this video, we discuss what it means to be a researcher. The word research has many different meanings depending on the context. While they vary in methods and dispositions, researchers do share some generalizable goals and habits of mind, which are transferable between projects, contexts, and disciplines. When approaching college level research, you might feel overwhelmed at first, but whether you realize it or not, you already have relevant experience from daily activities. You might consider yourself a researcher, but you seek out and engage with information every day. This could be as simple as choosing a restaurant, or as complex as deciding what candidate to support, or where you stand on an issue. Even if these examples seem unrelated to the work that you might expect to do in a college class, each involves activating goals and habits of mind that are central to performing academic research. Let's look at five mindsets or goals that you can bring with you to college research. One, knowing your context. Two, asking questions. Three, gathering information from other sources. Four, collecting your own evidence. And five, sharing what you learned. Both inside and outside the classroom, finding information that fits your needs and context requires some reflection on what those needs are. What is your research context? Is this for everyday needs or a college class? The answer to these questions will affect your level of formality and how much you adhere to a set process or guidelines. Your everyday research, like choosing a restaurant, will be a less formal and documented process, while your academic research will require more set guidelines and steps. Research is more than just the process of looking up and synthesizing information. Research begins with inquiry, an active state of questioning and exploration. Your role then is to be curious, to be interested in things that you don't know or understand yet, and to navigate answers you didn't expect. Even ones that go against your prior assumptions or beliefs. The questions you want to answer will help determine the kind of research you do and the kind of information you're looking for. When choosing a restaurant, you might ask, what kind of food do I like? What are my options in the area? What are the highest rated restaurants? Which restaurants match my group's preferences, budget, and dietary restrictions? Similarly, most academic research has a research question at its core. However, consulting an effective research question can be challenging. For example, yes or no questions or questions that have a straightforward answer won't allow much room to shape your research path or to make original contributions. A quick search can tell you that the answer to who is a Virginia Tech's mascot is a hokey bird. On the other hand, questions with too broad a scope, like what challenges do college students face today, will likely overwhelm you with too many potential directions. A productive research question, therefore, is open enough to allow multiple paths but not too broad for your project scope. For example, what are the benefits of on-campus housing for first-year college students? To begin answering your questions, you will gather information from sources to see what work others have already done in this area. This evidence enriches your knowledge and credibility with readers, transcending the limits of your own experience to benefit from the labor of researchers before you. The evidence you gather should meet your research needs and goals. For example, when searching for restaurants, it's helpful to find Yelp or Google reviews from people who've experienced the food and service. While each reviewer's expertise is limited to their first-hand experience, together, they give a sense of what to expect. When researching more complex topics, a different degree of expertise is needed from a variety of source types. For academic research, you'll be gathering information from a variety of source types while considering the reliability, expertise, and point of view of the creator. The requirements of your assignment will also help you determine what kinds of information to explore. Non-academic sources like Wikipedia can be useful during the planning and brainstorming stages even if they aren't cited in your final research product. It is likely you'll need a minimum number of academic scholarly or peer-reviewed sources, but they may not provide all the information you need. For example, you may need more up-to-date information that is difficult to find in peer-reviewed articles because of how long the academic publication process is. Because of the demographics of academic publishing and various academic fields, their voices and perspectives under-represented by peer-reviewed articles, so other sources like blogs, interviews, and social media can fill in some gaps. Your previous experience with the research project might have just been collecting sources on a certain topic, reading those sources, and combining the information presented. However, conducting research can also include creating new knowledge through experiments, interviews, and surveys and communicating the results of that work. This is called original or primary research, and your role as an investigator, controlling the focus of the inquiry. When choosing a restaurant, the question of your friends' preferences and dietary restrictions hasn't already been collected and can't be searched for online, so it requires you to do your own data collection and original research. In your academic research project, you may choose to interview an expert you know or survey your classmates on their experiences. Based on the evidence you gather, both from other sources and your own original research, you will draw a conclusion that answers your initial question. This conclusion is often a temporary end to work that might continue later. For example, your research on restaurants has a temporary end when you select one to go to for this outing, but you'll use the information you gather to select other restaurants in the future. Conclusions in academic research often present the current state of a project and outline areas for future research that could be completed by you or others. This communication of results is an essential part of research because all research is a conversation among many participants. Research as a process can be messy, even for experts. Many of these steps will overlap and blend as gathering evidence leads you to ask new questions and drawing conclusions leads you down new research paths. Research can be daunting and thinking of yourself as a researcher might feel uncomfortable at first, but keep in mind that you have transferable skills and experience from a lifetime of being curious and asking questions. You have unique perspectives and experience that allow you to make original contributions through thought, investigation, and reflection. Stay curious and happy researching.


अछ्सला मुलेगं स्ड्युदन्त, अव वसीम क्यम, इस से जी से तिज्टीझत लेक्चचीर, अशीरीज़ क्यम अप दिज्टीट लोगीग छैंग. कईसभी आप ज़ला आच्छी हूँँँँँँँँ. पिशन लेक्च्छर में हम बात के रहते है, 16-bit ALU को इंप्लमेंत करने की. जो प्रब्लम हमारे सामने आया था, जब आप 4-bit के different chips अपस में कोनेख करते हैं, तो केरी-bit है, वो एक 4-bit chip से, तुसे में जाएगा, तुसे से, तुसे से, स्प्रक्षन करने के लिए प्रफाम करने के लिए हमें कोई अलेदा स्प्रक्षन युनेड नहीं जाएगी, वोई जो 4-bit प्रल अडर है, उसी को युस करते हैं, करते क्या हैं, उसका जो A-input है, उसको उसी दरने देतें, जो B-input है, प्रल अडर का, उसके साथ हम एक सरकेट कूनेख करते हैं, अर गेट का, जो B-input को या तो इनवर्ट कर के प्रल अडर के इनपुट पे देते हैं, या उसी तना देर हैं. जो अगर हमने आद करने तो नमबस, तो वो जो सरकेट हैं, जो B-input पे लगाया, तो अपते आझती लिख सरकेट का, result आजाईगा. में में आप आवक चीन भेड अन, इद बेट, त्री वड, सक्झा� form the varying bes in the subject, you can implement the subject. कैसे इसी सरकेट को इसी सरकेट को आप आपस में जोडते जाएं, तो वो वो मः स्विख़ी ती आप तो ज्फाःीं थी बईगा. इसके बात आमने दिशकच्यों श्वोगी ती अर्ठ्माटिक लोगिक युनेत प्रेई. तो बँड़े पट़ा जीत़ जीतन कासगान मीक्रोप़ोलसी�र चैच tane keiat बनत क्रोपौँず करना ज Джैसे ची वोतबोल नकरे के आखः क Global आखन चतर room J decir pala क्रोफेर टॉक सीन पोथी हily medidas on the आच पूईike kar लोग के हैट केरी जन्रेटर के अध्वोट है, जो केरी इस अध्वोट हैं, वो आप कहाँ अताच करेंगे, बैसिक लिए वो हर फोर भित एल्यु की जो केरी एन उसके साथ अताच करेंगे. अध्वोट है, एन लोग के जन्वों के जन्वोट है।愚 BB usar �ㄹ�, �i or �y for Relächlich Rileyよaku skisi gases of each of these ALU�s are 4 betлемy. So, the output of AlU 0 gives bats 0 to 3. Similarly, output of AlU 1 gives-out the results for bats souffle to 7 and similarly for ball shot and value 0 and value 1. Now looking at the carry inputs, the pictures zero is carry out four, similarly the carry in to alu one is carry in for the output carry output from alu one is carry out eight, the carry in to alu two is carry in eight similarly the carry out from alu two is carry out twelve, the carry in to alu three is carry in twelve, from ALU 3 is carry out 16. Now in order to implement a 16 bit ALU the carry output of each ALU is connected to the carry in of the next ALU. So for example the carry out of ALU 0 is connected to the carry in of the ALU 1. Similarly the carry out of the ALU 1 is connected to the carry in of the ALU 2 and finally the carry-out of the ALU-2 is connected to the carry-in of the ALU-3. Now, the carry has to propagate through the ALU-0 through ALU-1, 2 and ultimately it reaches ALU-3. So, the last most significant ALU, the ALU-3 cannot perform an operation unless it has the carry-in 12. The carry-in 12 cannot reach ALU-3 unless the ALU-2 has generated a carry-out 12. Similarly, ALU-1 has to generate a carry-out 8 so that it reaches the carry-in of ALU-2. So therefore, the carry-out 16 from ALU-3 is delayed. This means the result of the arithmetic operation or the logical operation is going to be delayed. If you have a 32-bit ALU, you would be having 8 such gates connected to each other through their carry-outs and carry-ins. So, the last ALU which would be the 8th ALU would give a carry-out after a delay by a factor of 8. Now, to eliminate the carry propagate which propagates from one ALU unit to the next and to the next and to the next, we use the 381. 381 as we said before has two outputs, the group carry outputs. So, ALU-0 has the two outputs P-0 and G-0 the propagate, the carry propagate term and the carry generate term. Similarly, ALU-1 has the two terms P-1 and G-1 the propagate and the generate term similarly ALU-2 and 3 both have the P and G outputs. Now, P and G outputs are equivalent to the carry-4 output seen earlier. So, whenever these two bits are set, this indicates the carry-4 is there. Now, a look ahead carry generator is used. It has 8 inputs having the inputs G-0, G-1, G-2, G-3 and P-0, P-1, P-2 and P-3. So, the carry propagate and carry generate terms generated by each of the 4 ALUs are connected to the input of the look ahead carry generator, which are the carry terms generated by the look ahead carry generated generator on the basis of the generate terms and the propagate terms. Each of these carry outputs are connected to the carry ends of the appropriate ALUs. So, for example, C-1 carry out from the look ahead carry generator is connected to the C in 4 of ALU-1, the C-2 carry 2 output of the look ahead carry generator is connected to the C in 8 of ALU-2 and similarly the carry 3 output of the look ahead carry generator is connected to the C in 12 of the ALU-3. So, now ALU-3, the last arithmetic logic unit receives the carry after a gate delay of 2 instead of the carry having to propagate from ALU-0 through ALU-1 and ALU-2. Now, let us have a look at 16 bit ALU implementation based on 4 381 chips and 182 chip which is the look ahead carry generator chip. Now, looking at the diagram, we have used ALU-0, ALU-1, ALU-2 and ALU-3. So, ALU-0 adds or subtracts or performs arithmetic and logical operations on bits 0 to 3. Similarly, ALU-1 performs arithmetic logical operations on bits 4 to 7 and similarly ALU-2 and ALU-3 perform operations on the most significant 8 bits. The inputs of all these 4 ALUs are connected together shown through the thick lines and labeled A and B. Similarly, the outputs of each of these 4 ALU units are connected together. So, they give an output from bits 0 to 15. The 381 can perform up to 8 different operations. So, any of these 8 different operations are selected by the function select lines S0, S1 and S2. So, the function select lines S0, S1 and S2 of the 4 ALU circuits are connected together.  So, all the 4 ALUs have to be configured to perform a subtraction.  Each of the 4 ALUs have the carry generate term and the carry propagate term shown at the output and each output has bubbles. That means the G term and the P term are active low. The look ahead carry generator 74182 has 8 inputs G0, G1, G2, G3, P0, P1, P2, P3. They are all active low. The output is C1, C2 and C3. So, the G and P outputs of each of the ALUs are connected to the G and P inputs of the 182. C1, C2, C3 carry outputs are connected to the carry-ins of the appropriate ALUs. So, the carry 0 is directly connected to the carry-in of the first ALU, ALU 0. It is also connected to the input Cu of 182, the look ahead carry generator. The output C1 is connected to the carry-in of ALU 1. Similarly, carry 2 is connected to the carry-in of ALU 2. And similarly, carry 3 is connected to the carry-in of ALU 3. We have just looked at the implementation of a 16-bit ALU. We used 4 381 integrated circuits. We had connected them together. We have also used a look ahead carry generator to implement the 16-bit ALU. Now, let us have a look at the comparator unit. Comparator unit is another functional device. In the last lecture, if you remember, we had made a comparator circuit boolean expression. We had discussed a 2-bit comparator unit. That means, you have two numbers, two numbers of two bits each. When you compare, the comparator will compare the two numbers and compare the two bits. So, if both the numbers are equal, the output A is equal to B, then it is one, indicating that the two numbers are equal. Similarly, if A is greater than B, larger than B, ,ब लज़ दन बी , कमप्रोछ़का जो अदब्ष्ट है , A greater than b वो वान होजईगा. उसी तना अगर आ जो यो आत्पड़ है अगर a is less than b, खम्प्रेछ़ splashingड का जो अदब्ष्ट है, a less than b वो वान నౌల్న్ల్స్త్ర్స్త్త్లుగతాత్సర్వ్న్ నింిత్ల్మార్యాస్నాలికో�掌ండిఉవసా్మాత్లాలిదికోలా నారిలార్స్ కోవిలుసాలాలు. भी चूर भूबाः और लोँद्सougher a capability of the circuit? भी लिग दूदंमेने में जी और ततींग soft cannot be used आोर लाई लीग फक catalog of wrap एक लगसी वे Negrois bono is यह बवॉठा paraglider क्या तती दासे छागना दो Odys », कि मैं कचा �vs.. आपना बन काो तगा लग साथ द numer जो एक प्वरेट़र हम ने बताए है ते तो अगर हम तो तो थो तो भीध रेट वरेट़ करतेड़ है। धौ वे च्दकष्डम और तो, बर दीड़़्ीचन तो बचिन्च्टन, ने बताद़ कक में चलक यह तो तो तो ठीड़ में ठेदर है, let us discuss, why we need to have that extra logic to attach the two bit comparators. let us suppose you have, two numbers 8 and 9. 8 is in binary, how do we represent it? 1, 0, 0, 0. 9 is in binary, how do we represent it? 1, 0, 0, 1. now, both are 4 bit numbers, now when you compare them, आब अपृत की ंँई, बी, है। तो इसु अद प्रेटर युनेज तो डऱ चो। नहीं थब युनेज तो वद करेगा अद करेगा अदच़े युनेच खेूता साग फात हो। कैसे हमारे बास आगेगी ताला जो युनेच है। तो तो deep, now what i have done is that तो at the two most significant beds मेंनरेँ बट्सद आतोरी था बरता मेंही भी भमन rápता तो at the two most significant beds तो 2 बट्सागा मेंने यह सहये नहीं एक आनता समझे था तो at the finer output of भर थादner is मेंने लिस बट्सागा मेंने नहीं यह सह छ़क्य aerospaceि अखाद उसका a equals to b अपका 1 आजागा Indicating that a input is greater than b इस्तिना अगर अप तो नमबर्स 8 and 7 को खमप्रेर कर हैं 8 is 1 0 0 0 and 7 is 0 1 1 1 एक जो तुबट खमप्रेरतर है वो खमप्रेर करेगा 2 more significant bits So 8 is the 2 more significant bits of 8 is 1 0 And the 2 more significant bits of 7 are 0 and 1 तो पहला जो खमप्रेरतर है, वो खमप्रेर करेगा 1 0 को 0 1 से यो तुब इमीजगत्ली से that 8 is greater than 7 तुश्रे खमप्रेरतर की जो तुबट आनी परडाएस में So there are different possibilities Circuit ultimately क्या होगा? खमप्रेरतर जो पहला वाल खमप्रेरतर है जो 2 more significant bits को खमप्रेर कर है तुश्रा वाला खमप्रेर्रटर है जो लीई सिक्लिप्रेंगन बेट को खमपेर कर है उंके आपफ़ोट से आपपस में ओर गेड कीग खमप्रेर्रेटर से प्रेरडाएस में अब अपने आपनी आपनी जोगेगा जो दूश्रा वाला ग़ेखा पलने hai, पिस लिक्त्रजे�倫 में तीन ऐकट्�jsk्यों सेकक की ड़ािए देी vontade की तीटेclassions derive� The extra labor has three openings derived in the last lecture, आ गट़्र दें लच्द की फिरसब्रठ्त सेकष्समें, आ और ब ligne look at suggestions in different expressions derived, आ गेटर दें पी, बार पक, मिस Himtha learners gets to implement completing the changes with a般. � LineAL Lao, इसको में soft. b 1 a 0 b 0 and of course, the output is set to 1 when a is greater than b similarly the Boolean expression derived for a equals to b output was a 1 bar a 0 bar b 1 bar b 0 bar plus a 1 bar a 0 b 1 bar b 0 plus a 1 a 0 b 1 b 0 plus a 1 a 0 bar b 1 and b 0 bar is key to implementation again a single or gets used for a char and gets used for a and different inverters use for a is key implementation exclusive or exclusive nor gets a b key jasakti a small inputs weight are a 1 a 0 b 1 b 0 output a equals to b is set to 1 when the two numbers are equal finally, the Boolean expression derived for the a less than b output is a 1 bar b 1 plus a 1 bar a 0 bar b 0 plus a 0 bar b 1 b 0 this expression can be implemented using an or gate 3 and gates and 4 inverters the input to the circuit is again a 1 b 1 a 0 b 0 and the output a less than b is set to 1 when a number is less than number b. Now, let us look at the 4 bit comparator circuit implemented using 2 2 bit comparators. So, you have a 2 bit most significant comparator and a 2 bit least significant comparator represented by m and l respectively. The 2 most significant bits of the 4 bit number are compared by the most significant comparator and the least significant 2 bits of the 2 numbers are compared by the least significant 2 bit comparator. Now, let us consider different input combinations input number a is 1 1 0 1 which is 13 and input number b is 7. So, 13 is of course larger than 7. Now, the first comparator the most significant comparator compares bits 1 1 of number a and bits 0 1 of number b it immediately sets its output a greater than b and we have the answer. Let us consider the second case the number a is 0 1 1 0 which is 6 and number b is 1 0 1 1 which is 11 number b is greater than a. Now, the most significant 2 bit comparator compares bits 0 1 of number a and 1 0 of number b. Now, 1 0 is greater than 0 1. So, therefore, the comparator the most significant 2 bit comparator sets its a less than b output to 1 and we have the answer. Let us now consider the third case the number a is 0 0 1 1 and number b is 0 0 1 0 1 1 represents 3 1 0 represents 2. Now, the most significant 2 bit comparator compares 0 0 bits of number a and 0 0 bits of number b. Since both the 2 bits are equal therefore, the output of the most significant 2 bit comparator m is set to 1 for a equals to b output. Now, we do not have the answer the least significant comparator compares bits 1 1 of number a with 1 0 bits of number b. Since, 1 1 is greater than 1 0 therefore, the output a greater than b of comparator 2 the least significant comparator is set to 1. Let us compare let us see the fourth case number a is 0 1 0 0 number b is 0 1 0 1. Now, the most significant comparator compares 0 1 bits of the number a and 0 1 bits of the number b. Since, both are equals therefore, the a equals to b output of the most significant comparator is a 1 the least significant comparator compares bits 0 0 of number a and 0 1 of number b. Now, b is greater than a. So, the output of the least significant comparator a less than b is set to 1. The last case when the 2 numbers are equal. So, number a is 1 0 0 1 number b is again 1 0 0 1. Now, the output a equals to b of the most significant comparator and the output a equals to b of the least significant comparator both are set to 1. Now, let us have a look at the circuit diagram of the 4 bit comparator unit. The outputs of the most significant 2 bit comparator a greater than b is connected to an OR gate a is equal to b is connected to 3 AND gates. So, basically a equals to b output enables the 3 AND gates. Similarly, the output a less than b of the most significant comparator is connected to the input of another OR gate. Looking at the second 2 bit comparator the least significant 2 bit comparator it is a greater than b output is connected to one of the inputs of the AND gate. Similarly, a equals to b output is connected to the other input of the AND gate and a less than b output is connected to the input of the third AND gate. The outputs of the first AND gate and the last AND gate are connected to the inputs of the 2 OR gates representing the output a greater than b and a less than b respectively. The output of the second AND gate represents the output a equals to b. Now, if the most significant 2 bit comparator compares 2 2 bit numbers and finds them to be equal the a equals to b output is set to one which enables the AND gates. We do not have the answer the 2 bit least significant comparator needs to compare the numbers and it is going to set one of its outputs to one assuming the number a is larger than b the output of the least significant 2 bit comparator a greater than b would be set to one all the other 2 outputs would remain at 0. So, the output of the first AND gate would be set to one the output of the a greater than b OR gate would be set to one. Similarly, the outputs of a less than b and a equals to b would be set to one depending on the appropriate numbers. We have looked at the implementation of a 4 bit comparator unit basically 2 2 bit comparator units are connected together some external logic in the form of AND gates and OR gates is required. Now, by using this external logic the size of the circuit is going to increase. So, just imagine if you want to make a 16 bit comparator unit then a lot of external logic will be used. So, it would have been better if this external logic is inside the integrated circuit. The comparator chip if it is available then the connection of 2 2 bit comparators to form a 4 bit comparator would be easier. You do not have to use the external logic, the circuit size will also be small. If you want to use parallel comparators then you have to use external logic. Another way to implement these comparator units is to use iterative circuits. What are iterative circuits? If you remember the single bit full adder basically you implemented a 4 bit parallel adder using 4 of these single bit full adders. What did you do in that? You had only one single bit full adder, 4 of these circuits connected together and made a 4 bit parallel adder. You did not have to use any external logic in that. So, if single bit full adder is an example of an iterative circuit, there were 4 copies of it. Each copy is doing the same thing. The output of one copy is connected to the input of the other circuit. Similarly, the other circuit is an identical copy. The output of the other circuit is connected to the input of the other circuit and so on. So, iterative circuits we can use to implement a comparator. So, in comparator let us talk about A equals to B. How will the iterative circuit of A equals to B be made? An exclusive NOR gate is used to detect if the 2 bits are equal. So, if both bits are 1 1 the output of the exclusive NOR gate would be A1. If both bits are 0 0 the output of the exclusive NOR gate would be again A1. Now, iterative circuit exclusive NOR gate ka kaisa bhanega? Well, we have a combination of an exclusive NOR gate and an AND gate. Exclusive NOR gate ki output jo hai wo connect ho jaagi ek AND gate ke input pe. Dursre jo input hai AND gate ki wo ham permanently set kernenge 1 pe. So, what is the output of the AND gate? It is going to be 1 if the output of the exclusive NOR gate is 1. Agar exclusive NOR gate ki output 0 hai that means both the bits are not equal the output of the AND gate would be a 0. Now, let us consider another circuit. Just may again ye ap ke pas exclusive NOR gate hai connected to the input of another AND gate. Jo pale wale circuit ki output hai from the AND gate. If it is connected to the input of the second AND gate, second jo module bhanega jo iterative circuit bhanega usme. Ab huma hai pas kya hoge? Huma hai pas ek circuit bhanega jo 2 bits ko compare kar rahe hai. Agar chek kar rahe hai ki 2 bits equal hai ke nahi hai. So, jo dursre module hai again it would be comparing the second bit of number A and the second bit of number B. Agar equal hai exclusive NOR gate ka output ki a aega? 1 aaja aega. Palega bhi output 1 tha. So, output of the 2 bit circuit would be a 1. Agar exclusive NOR gate ka output 1 nahi hai that means the second bit of number A and the second bit of number B both are not equal the output of the AND gate would be a 0. So, similarly you can implement an 8 bit, 16 bit, 32 bit comparator unit using these iterative circuits. Isi tana A greater than B jo circuit hai uska bhi ek iterative circuit bhanega aaja aajat tha. So, you would have identical copies they can be connected together. Let us have a look at the circuit diagrams of both these circuits. Let us have a look at the iterative circuit implementation of A equals to B function. Seen in the figure we have module 0 and module 1. These 2 modules represent 2 iterative circuits for the A equals to B function. Module 0 looks at bits A 0 and B 0. If they are equal the output of the exclusive NOR gate is 1. The input of the AND gate is permanently set to 1. The output of the AND gate would be 1 if bits A 0 and B 0 are equal. If they are not equal the output of the AND gate would be a 0. Now looking at the second module module 1 it compares bits A 1 and B 1. Now if the output is A 1 that means bits A 1 and B 1 are equal. If previously bits A 0 and B 0 had been equal the output from module 0 would be A 1. Now what is the output of module 2? In case the numbers are equal the AND gate of module 1 would have both its inputs set to 1. The output would be A 1 indicating that both numbers are equal. Let us suppose that bits A 0 and B 0 are not equal and bits A 1 and B 1 are equal. What is the output of the AND gate in module 0? It would be A 0. What is the output of the AND gate in module 1? It would be 0 because one of the inputs to the AND gate is A 0. Let us consider the case when bits A 0 and B 0 are equal and bits A 1 and B 1 are not equal. So the output of the AND gate in module 0 would be A 1. The output of the exclusive NOR gate in module 1 would be A 0. The output of the AND gate in module 1 would be A 0 because one of its inputs from the exclusive NOR gate is A 0. To form a 4 bit comparator unit similar modules can be connected together. The input in module 0 which is connected to 1 is known as the cascading input. Similarly the input to the AND gate in module 1 is also known as a cascading input. Similarly the outputs from the 2 AND gates in module 0 and 1 are known as the cascading outputs. So in order to form a 4 bit or an 8 bit comparator unit the cascading inputs are connected to the cascading outputs of the appropriate modules or the iterative circuits. The cascading input of the least significant iterative circuit module 0 in this case is connected to 1. The output A equals to B would be obtained from the most significant iterative circuit or module. Let us now look at the iterative circuit implementation of A greater than B function. Seen in the diagram we have a 2 bit implementation of the A greater than B function using the iterative circuits. Looking at module 0 it has an exclusive NOR gate, 2 AND gates, an OR gate and an inverter. Let us suppose A 0 is equal to B 0. The output of the exclusive NOR gate would be A 1. Since the cascading input of the AND gate is permanently set to 0 the output would be A 0. Now the output of the OR gate in module 0 would only be A 1 when A is greater than B. Similarly looking at module 1 the output of the OR gate would be A 1 when A 1 is greater than B 1 or the cascading output from module 0 is A 1. 4 bit, 8 bit or 16 bit comparator units can be formed which generate the output A greater than B by connecting these modules together. So the least significant cascading output is connected to the cascading input of the second module. Similarly the cascading output of the second module is connected to the cascading input of the third module and so on. In this case the cascading input of the least significant module is connected to 0. The cascading output of the most significant module would give the function output A greater than B. To implement A less than B function a similar iterative circuit can be formed and such circuits can be connected together to form a 4 bit, 8 bit or 16 bit A less than B function. We have just looked at the iterative implementation of a comparator circuit. In the iterative implementation basically we designed a single module and copies of that particular module can be used connected together to form an N bit comparator unit. A equals to B can be an example like similarly A less than B key B which can be connected together to form an N bit unit. Now commercially these comparator units are available based on the iterative circuit which we have just discussed. The 7485 is one such unit. It is basically a 4 bit comparator unit. Now in order to form let us say a 12 bit comparator unit you would get 3 of these chips and you would be connecting them together. As we mentioned before these iterative based comparator circuits have cascading inputs and cascading outputs. So cascading output of the least significant unit would be connected to the cascading inputs of the next higher unit. And similarly the cascading outputs of the second unit would be connected to the cascading inputs of the most significant unit. The inputs the cascading inputs of the least significant unit would be permanently connected to 0s or binary 1, 5 volts and 0 volts. The circuit which compares and generates an output for A greater than B and A less than B its cascading inputs are connected to 0 volts. And the circuit which compares A equals to B has its cascading input connected to 5 volts. Let us have a look of the implementation using the 7485. To implement the 12 bit comparator unit 3 4 bit 7485 4 bit comparator chips are used. The least significant 4 bit comparator compares bits 0 to 3, the middle comparator unit compares bits 4 to 7 and the most significant comparator unit compares bits 8 to 11. The appropriate inputs are tied together shown by thick lines. The cascading input of the first comparator unit is connected to 0 volts, 5 volts and 0 volts. The A less than B cascading input is connected to 0, the A greater than B cascading input is also connected to 0 volts. The A equals to B cascading input is connected to 5 volts. The cascading outputs A less than B, A equals to B and A greater than B of the first comparator unit is connected to the cascading inputs, the respective cascading inputs of the second comparator unit. Similarly, the cascading outputs of the second comparator unit is connected to the cascading inputs of the third the most significant 4 bit comparator unit. The outputs, the cascading outputs from the third most significant comparator unit A less than B, A equals to B, A greater than B are set to 1s or 0s depending on the 2 numbers. So, let us suppose A is greater than B, the cascading output A greater than B of comparator unit 3 would be set to 1. Similarly, if the 2 numbers are equal, the cascading output A equals to B of the third comparator unit would be set to 1. We have just looked at the implementation of a 12 bit comparator circuit using B4 bit 7485 iterative based circuits. Connection was straight forward. उस में कोई कोंप्लिकेशन की बातनी जो cascading inputs and cascading outputs आन वो बेसिक्त हैं में लिए। करनें. And as I have mentioned before, you can implement 16 bit, 32 bit, N bit comparator unit बनाशकनें by connecting the chips together. Now, the next important unit which we need to talk about is the decoder unit. Decoder unit commonly used with the digital logic man. Decoder circuit haggya. Basically, a decoder circuit has multiple inputs and multiple outputs. Now, if you apply a multi bit code at the input of the decoder, it is going to select one or more than one of its outputs to indicate the presence of that code. So, you have a circuit multiple inputs, multiple outputs, यक code of apply करेंगे आनप्लिकेशन की अबआजासे आपभ़ट्पे यहीग बिट आपभट अपट्ट आपट्टट होँगागया यहा मल्टिपल आपटटट होगागया. Let us consider an example. Let us suppose you design a digital lock. ॐ ॐ ौ ौ ौ Because you have toalign a circuit which accepts number 11 and sets the output to 1. One indicates that this door has been locked.. Similarly, you need to unlock the door of a circuit which accepts the combination of 1001 and it sets a output to 1.. which indicates that the lock has been unlocked. Now how do we implement the door lock circuit ?  आद़्ीट की और ठॉगाडिय प्रिच्रे के खदूए. , let us have look at the circuit which unlocks the door , the combination is 1001 number 9 , again you would use another AND gate, four input AND gate , one jo hair directly connected ho gaya . Uske ba though jo zeros are a they are connected to the inputs of the AND gate through two inverters and finally the last bit one it is directly connected to the input of the AND gate . So, the output of the AND gate would अपने चार इंपुट कोमनेशन अपलाए की किसी दो कोमनेशन पे सरकेट अपलट वन होंगे 11 पे लोग करेगा 9 पे अनलोग करेगा कोई आर कोमनेशन देंगे the circuit would not work now the most common decoder which we use is a 2 to 4 decoder circuit its 2 inputs and 4 outputs now how does a 2 to 4 decoder work basically 2 inputs then what combinations can be 0, 0, 0, 1, 1, 0 and 1, 1 on output we have 4 outputs as we have said before so if 0, 0 is selected one of those 4 outputs will be activated when 0, 1 input combination will be applied the second output will be activated the other 3 outputs will be inactive similarly 1, 0 combination will be applied and after that 1, 1 will be applied so the appropriate outputs will be activated let us have a look at the implementation of this 2 to 4 decoder circuit let us have a look at the function diagram which represents the function of this 2 to 4 decoder let us first have a look at the electronic door lock the circuit shows 2, 4 input AND gates and 3 inverters the electronic door lock is within the box the inputs to the electronic door lock are A, B, C and D the outputs are of course 2 lock and unlock now when the combination 1, 0, 1, 1 is applied at the input the lock output is set to 1 and when a combination 1, 0, 0, 1 is applied the unlock output is set to 1 for all other combinations the lock output and the unlock output remains at 0 now let us look at the implementation of a 2 to 4 binary decoder before we look at the circuit diagram let us look at the function table of the 2 to 4 binary decoder the 2 to 4 binary decoder has 2 inputs and 4 outputs the 2 inputs are represented by I, 0 and I, 1 and the 4 outputs are represented by O, 0 the output 0, O, 1, O, 2 and O, 3 now for the input combinations 0, 0, output 0 should be active similarly for input combinations 0, 1, the output 1 should be active all other outputs should remain at 0 similarly for input combination 1, 0 the output 2 should be active other outputs should remain inactive and finally for the input combination 1, 1 the output 3 should be 1 the remaining output should be 0 now this function can be implemented through a set of 4 AND gates and 2 inverters so as seen in the diagram the 2 inverter outputs are connected to the inputs of the first AND gate O, 0 now when input 0 and input 1 are both set to 0 the outputs of the inverters are 1s and the output of the first AND gate O, 0 is a 1 similarly looking at the last AND gate the non-inverted inputs are connected to the inputs of the AND gate so when both inputs are 1s the output of the last AND gate is 1 similarly for the second AND third AND gate a combination of inverted and non-inverted inputs are applied we have looked at the implementation of a sample 2 to 4 decoder there are different types of decoders available in different configurations 2 to 4 decoder have 3 to 8 have 4 to 16 have dual 2 to 4 decoders and different combinations can be attached and connect to form larger decoders we had read in the beginning BCD to 7th segment decoder that is also a decoder it is different from this particular 2 to 4 decoder in BCD to 7th segment decoder you apply a certain code a BCD code its multiple outputs are activated depending on the appropriate segments we will see that later similarly you have BCD to decimal decoder that means you apply a BCD number how many outputs are there 10 outputs because it is a BCD to decimal so output 10 must be 0 to 9 so each output would represent 1 decimal number from 0 to 9 now where do we use these decoders basically in digital systems there are 2 types of applications where decoders are used one application is selection of different devices in any computer or any digital system you have different devices so which different devices they are selected one after the other so how to select basically every device has an address so let's say a device A let's say modem you have kept its address 0 1 1 0 another device is hard disk you have kept its address 0 1 1 1 so if you have to select modem then what will you apply to the code 0 1 1 0 which is its address similarly if you have to select the hard disk you will apply its code where will you apply this code you would have a similar decoder circuit decoder's inputs will apply this code its appropriate output will be activated decoder's output will be attached to input pins of these devices which will select these devices this is the same example which we studied door lock and unlock if you expand it let's say you have 4 inputs so how many input combinations you can apply 16 input combinations similarly if you expand that circuit you will have 16 outputs so that means you have 16 rather 8 doors which you can lock and unlock 0 0 1 0 0 0 1 would open that same door similarly 2 will lock 3 combination will open that same door here you can control the light switches on or off or you can control any device so decoders can be used to select devices and in fact in computer system this is what you are doing second application instructions when you write a program when you compile it all the code changes in machine code in binary code this code when you run program in computer so your computer fetches one instruction looks at the binary pattern so what is binary pattern basically with every instruction there will be a unique binary pattern which will tell you what is this instruction adding, logical operation performing there is a command that you have to save something in memory how computer will know what operation to do basically the binary code will apply to a decoder input one output of decoder will be activated that output will be connected with appropriate device so let's say 0 0 0 1 the add operation appropriate output will be activated it will be attached with an adder unit so it will tell the adder unit to add similarly the instruction 1 0 0 0 could mean save a variable in the memory so when you apply this 1 0 0 0 code at the input of a decoder the appropriate output would be selected the appropriate output will be connected with memory chip memory will be informed that you have to save a particular variable let us now look at some commercially available decoders we have a 2 to 4 decoder and 2 of these decoders are available in a chip so let us have a look at the function diagram of this decoder and the circuit the 2 to 4 decoder is slightly different from the circuit which we have just seen the input is incorporated so whenever you use decoder you would first enable the chip when you don't use it you would disable the chip so let us have a look let us have a look at 7 4 1 3 9 dual 2 to 4 decoder that means in this chip you have 2 to 4 decoders the function table of this 2 to 4 decoder is a and another input which is the chip enable input g it is active low the outputs of this 2 to 4 decoder are y0 y1, y2 and y3 they are all active low now in order to use this decoder the enable pin has to be activated so since it is active low it has to be connected to logic 0 to activate the chip so as seen in the function table the first row g input is 1 therefore the output of all the 4 pins remains a 1 no matter what the input is if the enable pin is set to 0 as seen in the second row if you apply an input 00 the y0 output is selected since it is active low therefore you see a 0 there the remaining outputs are set to 1 or remain at 1 similarly when g input is 0 the chip is activated the inputs are 0 1 y1 output is selected it is seen to be 0 remaining outputs are set to 1 for input 10 the output y2 is selected for the input 11 the output y3 is selected looking at the circuit diagram of the 7 4 1 3 9 you have 4 9 gates with bubbles at the outputs 9 gates have been used because the outputs are active low similarly instead of using 2 inverters you see 5 inverters 1 inverter is used for the enable pin it is active low so inverter converts the active low input to active high and connects it or enables the 4 9 gates the inputs p and a are connected through 2 inverters the reason for connecting 2 extra inverters is to reduce the load seen by the input let us suppose the 2 extra inverters are not available at the inputs b and a so if this particular decoder circuit is connected to the output of another logic circuit how many unit loads would it see basically it would see an inverter and 2 9 gates so 3 unit loads are seen so if you remember the fan out term any circuit can be connected to a fixed number of gates so in this particular case if the 2 not gates are missing the fan out assuming the fan out to be 10 the fan out of the circuit would reduce to 7 by connecting the extra inverter the unit load has been reduced from 3 to 1 we have just looked at the implementation of a dual 2 to 4 decoder as I have said so there are different types of decoders which can be implemented in the next lecture until the next lecture khuda hafiz


Good morning YouTube. Thank you for watching this episode of the Trucker Josh Vlogs. I am Zachary Hill from Hills on the Road of Life and today on this Road of Life I'm riding through a rut. Confused. I slept at the customer, right? And that's because I wanted to be loaded first thing in the morning. I'm telling a story. I wanted to be loaded first thing in the morning, right? So I made sure I was here first thing in the morning. I went and read their sign and it said gate opens at 7 a.m. No entry before then. Okay cool 7 a.m. sounds good to me. So I woke up at 6 30 and I looked over to the gate. I'm like okay there it is it's still closed and then I look over beside me and one of the trucks that was parked beside me for the night is gone. Where'd he go? He was empty so suddenly he was loaded in life. He had to get loaded first. Where'd he go? Right diesel? We were both confused so I'll walk diesel, get myself ready. And then all of a sudden I see across the yard over there. He's inside the gate already. What? How'd he get in there? So I scramble get all my stuff ready get you know get get the truck ready to go finish up with diesel and then I quickly go to the gate and I push the button and sure enough gate opens but it was exactly 7 a.m. so I'm like all right cool well I'm right on time I don't know how that guy got in but I'm right on time. There's just one guy in front of me somehow. Okay I go around the yard and I get to the place where we line up to get loaded. There's three trucks in here already. Three of them. How did they get in here before 7 a.m.? Obviously the sign is wrong. Sign says no entry before 7 a.m. and I got to the gate actually at 6.59. Three people are in here before me. Three trucks. That means it's gonna take a lot longer for me to get loaded because there's only two bays to tarp so they'll load the first two and those two will go into the tarping bays, tarp their loads and me and this guy in front of me here at the third guy on the fourth. We're gonna have to wait for them to finish tarping before we can go in their tarp. We're only allowed to tarp in the tarping bay. I showed you it's really fancy. How did they get in here? Apparently the sign is flexible. No entry before 7 a.m. but sometimes entry before 7 a.m. They haven't started loading the guys in front of me yet. So obviously they only start loading after 7 a.m. but you can get into the yard before 7 a.m. Interesting. Good to know. Good to know. Next time I guess I'll be at the gate at 6.30. Well then I think that guy was in here before 6.30. Well I'm number four. Number four. So we're probably not going to get delivered today yet. I'll probably deliver tomorrow morning. We're going down to Brainerd, Minnesota. By the time I'm out of here it'll probably be too late to deliver today. Huh. Oh well. Now we know. About the same as our last one. I tried to get the crease there to line it better with the top of the load this time. I got it straight but I was in a little bit of a rush. There was a guy that pulled in right behind me just as I was tarping the load and he needed the tarp bay to tarp his load. So I was in his way so I wanted to hurry up and you know be polite and not take forever. So I quickly rushed a little bit and I'm happy with it but you know I'm only going 300 miles with it.  I'm getting unloaded today yet. The back here you'll see this is what bothered me the most but I did get the crease proper on the top there. We're not on this side and this side wraps around a little further than that side. Like I said the other day we are always our biggest critics. We are our own biggest critics. That's okay. It's doing the job right? We actually the driver who was behind me was I guess in a bit of a hurry and he came to help me with my tarps and that's why this is uneven here. I appreciate the help so I'm not complaining but he wasn't as focused as I was on getting it exactly lined up. I don't want to pass off the blame but sometimes it's just the honest truth. He didn't line this back one up straight for me when he was started tacking it down here but that's okay. Not a big deal. I appreciate that it came to help and it's all wrapped up on this is playing little peekaboo here again. What are you doing to me? That's okay. It's always good to help your fellow driver. These tarps don't have to be perfect. They don't have to look perfect. It doesn't matter. This is good. All it's supposed to do is cover the load just in case I run through some rain. It doesn't really need to be tarped. To be perfectly honest with you this load does not need to be tarped. It's a beautiful sunny day and it's just going 300 miles down the road on a sunny day. It doesn't need to be tarped but they want it tarped. So customer wants customer gets. Their load gets tarped. This would be more so for winter time when there's a lot of salt and debris on the road.  That's okay. I don't mind tarping and especially there they have those fancy tarp machines that I showed you on Monday. It takes very easy. There's nothing to complain about. That's the load though. Nice little Christmas present on its way down to Brainerd, Minnesota from Canora, Ontario. We talked here real quick to get a video uploaded and I just wanted to get that going back there. I have a mobile Wi-Fi so everywhere I go I have pretty good Wi-Fi. Either Canada or the States. It works on both sides of the border. That helps a lot with what I do here on YouTube. And I had to make sure I had my passport ready and old documentation and everything else ready because I'm gonna get to the border right away. I'm just outside of Fort Francis Ontario on the Canadian side. We're about to cross on to the US side so I am now ready. Prepare diesel. You ready? You got your passport? Let's pay for towel here. That's not a passport man. They're not gonna accept that. You can't just write Lord of all Weasels on a napkin. It's okay. We all got alerts sometimes. You're 11 years old now. You got to show them your own passport, okay? When you're crossing the border with pets, in all seriousness, jokes aside, you need to have proof with you of their vaccinations. Radies and whatnot.  I've never been asked for these records at the border before but if they do request them you do have to have them on hand to give over to them just to say, hey, he's up to date on his shots. Just like me, right? Nosey people, right? Nosey people. Order my dog's medical records to you, right Diesel? You're always up to date. Okay, anyways, let's go to America. Straps off of here as we can and we'll pull inside, take our straps off. Diesel, you're gonna do that part right? Gotta make yourself useful. You're not just here for a free ride, are you? I thought you worked for Kibble. It's pretty hot. Look, I still got this fan. I usually use this for night.  I was just soaked in sweat and then in the back there, I don't know if you can see it underneath, back there, that's a built-in Kenworth fan that I have in the truck. I have it pointed down at Diesel, blowing air on him, keeping him cool. Can't have the truck idling inside here, obviously. I'm done all my work.  He's just taking the lifts off now, so we should be out of here in about 10 minutes or so. Then I'm heading down to Hutchinson, Minnesota. I have a load there to pick up in the morning and it's going back to Manitoba, to a town near the border on 75 called LaTallier. I'm not sure what kind of freight this would be, it doesn't say on here. I rarely know. I only figure out what I'm hauling once I get there. Hopefully it's not too complicated. Whatever.  Should be back tomorrow. Might even get unloaded tomorrow, who knows. Clean. Finally got a shower. Between Canora and Brainerd there are no showers that I have an account for. There may be showers at some truck stops that I'm not aware of. I don't do that right often enough to know where all the little ones are. There's no pile of flying jays and that's where I always take a shower. So we're here in St. Cloud, Minnesota right now on the way down to Hutchinson and I was able to park over at the McDonald's in a temporary parking spot. We're allowed to park here just not overnight. I checked. So I parked here for about an hour, ran into a pilot and grabbed a shower, cleaned myself up. It felt so good. Now we're gonna get out of here. I'm gonna go to the customer at Hutchinson said I'm ready for the first thing in the morning tomorrow. Let's get out of here. There's the pilot right there. So he was just across the street. There's never any parking in this pilot. So if you're going to St. Cloud, Minnesota, you can stop in here and just grab fuel. Sometimes right now it's just jam packed with guys parked in the pumps.  It's risky. I don't fuel here because it's too congested. It's a very small lot and very often you get jammed up with people parking wherever they want. So I usually go to the pilot at exit 100 on I-94 in Minnesota. That's in Alexandria. That exit's a little funny though. You got to make sure you take the right exit to get on and off the freeway. You'll see what I mean when you go there. Or you can look at it on a map. But that parking lot's a lot more usable. It's a big lot and the pumps don't usually get as congested. That's where I usually go. I very rarely stop here. I only stopped here because this is right on my way to Hutchinson and I was kind of desperate for a shower. I almost didn't find parking but you know, lucky for me worked out this time, right Diesel? This is I-94. We're gonna get on I-94 Westbound just for a few miles. About five miles, seven kilometers on Minnesota 15 southbound down into Hutchinson. Not too sure what kind of stuff I'm picking up. By the looks of it, I looked it up on Google. It looks like it's gonna be some kind of steel parts, steel building materials by the looks of it. We'll find out in the morning. Whatever it is, I'll take it. I found myself a quiet street parked down. Can't really see it. Not much light is being picked up but there's about two businesses on this street and that's a dead end that way. All of this is obviously commercial land that's probably for sale. Those lights right there, that's where I'm loading in the morning. The yard is practically a quarter mile that way. They told me I wasn't allowed to park in the gate or on their driveway there. They're like, no, no, you're not allowed to park on our property or in our driveway. We're sorry. They actually suggested I went and parked at Wal-Mart, like, way across town, way over there. I looked at the map and I saw this road going through here and I figured, well, it looks like a pretty quiet road. We'll check it out. Sure enough, yeah, it's a business road. It's like an industrial road. Parking along the sides here. I've seen cars on Google Maps parking along the sides here. Sure enough, there's no signs here saying no parking. Very quiet street. Street lights. So I got a park right underneath the street light, which is important to me when you're on these quiet roads. I don't want to park in the pitch black if you don't have to. I was finding a nice light to park under. And big open grass fields for the weasel to run around in. Speaking of, he's in here somewhere. There he is. You see him? Hey, Deezu. What are you doing there? All right, let's... One good thing about these steps on these Ken ones is it's a nice, pretty low step. So I don't always have to use his fancy steps. One sec here, Deezu. One second. Let me get all my... This shouldn't be here. Okay, I trust you, buddy. Okay. Good boy. Yep, that pulls yours right there. No, it's going to be our friend. It's going to light us up all night. You go and mark it if you want to. It's going to be a good night. It was a good day, that's for sure. I started in Kenora today.  Started in Kenora this morning. We got loaded, tarped, got down to Brainerd, got un-tarped, got unloaded, and made it down to our customer where we're going to load first thing tomorrow morning. So it was a very productive day. Very happy with it. We drove about 750 kilometers, I think, which is under 500 miles. And then tomorrow we should be able to make it back into Manitoba. La Talle is just into Manitoba. I'm thinking, I don't know if I'm going to be able to get there before end of business day. I'm going to try. But if not, I'll just sleep right in La Talle. They have a little parking lot there. Sleep right there, deliver first thing Friday morning. And then I guess I'll call and see if they've got something short to do. But I think I'll be going home then because we have a wedding to go to on Saturday. One of my wife's friends is getting married. And I'm her plus one. Excuse to dress up, eh? Careful if you're going on the road there, weasel, okay? I know it's a quiet road. And that's a dead end. There's not going to be any traffic coming from there. But I did see, because that's a dead end, it's got like a big turnaround spot over there, right?  Can you blame them? I'd love to do burnouts too. But it's not a weekend, so I don't think they'll be here today. It's a Wednesday. They should be at home. Hasn't school started? They should be in school. Or college or university. Or trade school. That's where they should be. Trade school. That makes the most sense. Alright everybody, thanks for hanging out with me today. Didn't do a lot of filming, but we got a whole vlog out of it. We'll see you tomorrow. We'll put some freight on this trailer. We'll head back on up to Canadian. I hope you join us. If you haven't already, hit that subscribe button. Go down below into the description below my videos. A whole bunch of links and stuff there where you can find me on social media. There's links where you can support us if you want to as well. If you do support us on Patreon, we release the videos early there for everybody to see. Other than that, I'll see you right here on YouTube tomorrow morning. Take care.


How good or how bad could a content delivery network perform? well That could be determined at the very basic level using a mathematical model True. However, if you are interested in assessing the actual performance of large-scale content delivery networks, then we may have to carry out experimental Analysis for that in this module. We are going to look at a very well-known example from Raj Kumar Bhaiya in the content delivery network Book that I have already shared with you in this particular experiment Overlay networking that is overly routing which is the routing between Peering agents which does not involve the shortest paths is Is carried out and is compared to the direct or the shortest path Now this experimental setup would be then used for creating some data and that particular data is analyzed and some findings are made So what is the experimental setup? The experimental setup is to collect the data to optimize the shortest paths and the Indirect paths which are based on overlay Between edge networks. Now what are edge networks? Edge networks are tier 3 or tier 4 networks Which are residing either on the customer end or at the enterprise origin servers Now these particular edge servers are going to provision the objects which are requested by the client Now this could be one direct delivery mechanism like shortest path routing or BGP routing but sometimes because of the Assumption that everyone's going to take the shortest route the shortest path or the direct route turns out to be more Delay oriented for that routing overlays are basically specialized devices Which are routers or gateways Interior one networks which behave as an intermediate node for creating an indirect path between the server and the client The example platform that the authors have adopted is from Akamai Akamai is a well-known Content delivery network platform. So the measurements are done on CDN clusters the clusters are basically groups of servers Which are spread over the whole world now the Arrangement or the platform that the Authors have adopted is 1100 clusters from over six continents and 77 countries and you can see 630 cities. There are 1100 cut clusters Now these clusters are some of these are placed near the core servers around 15% of them and Around 85% of them are near the edge servers the intermediate nodes actually forward the traffic from the core servers because mostly the the Edge servers or the Origin servers are placed on the core ISP. So they use overlay routing to deliver the content to the clients Now Typically, there's an important point that typically these the servers in one cluster Are connected to a single service provider? It's something which is pretty obvious But it was declared as one of the design principles for this particular experimental study the data which was collected was collected using simple programming of Automation of pinging so it's an IPM ICM P echo request echo reply mechanism where 64 bytes of Requests were initiated from every Cluster to every other cluster so you can think about Mesh of 1100 clusters So it was done every two minutes so correspondingly since the number of nodes was very large So around the ten requests were being received every second at every node This activity was performed for four weeks and the duration was 1.5 hours Every day and the each path actually between every node to every every cluster to every other cluster was probed for 3,780 times it means that this was repeated so many times to make sure that the readings Are more average and there are hardly any anomalies. So the total probes turned out to be 652 million. It's a very large number. So this actually is a good Reliable data that can be banked upon so the overall findings were in the represented in the form of some tuples that included the time stamping identifiers of source and destination the direct round trip time the one hop shortest round trip time and Three hop shortest round trip time three hearts hop shortest round trip time actually means that the Indirect parts actually Instead of making direct trip go through up to three hops So this actually is the operation of how the overlay networking works This is more into the arrangement between different Edge and core serve core clusters. These clusters were placed across different continents seven continents and 15% of these were the core clusters and around 85% were the edge clusters So the mnemonics or the abbreviations are obvious for Asia. It is a s for South America. It is essay Now the findings actually start with the data collection So you you can see we have data which is categorized as Latency reduction percentage. What is that? It is actually the difference between the latency incurred in direct delivery of the object from the server to the client and The overlay path that is one two three pops Based round trip times now the difference between shortest path. That is the direct path and the overlay based path Actually was represented in the form of these five columns So the first category is actually the autonomous system to autonomous system That is you can say a cluster to cluster category. For example, Africa to Asia Now less than minus 10% actually means that the indirect path is in fact slower than the direct path That is against the intuitive argument that was being made Then we have 10% which is comparable almost the direct and indirect path would incur the same delay And then we have marginal improvement that is 30% improvement in terms of time using Indirect path or using overlay and then we have 30 to 50% significant improvement and then we have The more than 50% that is the indirect path takes Less than half of total time then it takes through the direct path Now the analysis between Of comparison between direct and indirect path is going to help us evaluate the performance And then we can think about making some recommendations But for analysis the data set was divided into buckets that I've already explained The findings actually are that the best indirect paths were 10% slower than the direct path now interestingly around 15% of the Paths between different clusters fell into this category Now was this argument Wrong that indirect paths result into better latency. Well, it is only 15% It means around 85% are the ones that have shown overall improvement See we have the 10% bucket where the direct and indirect are almost equal So 24.7% actually result into almost equal performance than direct path So it means that we can think about 40% overall scenarios or Paths where the autonomous system to autonomous system traffic was Being delivered almost equal to or less than equal to the direct path but overall the Results are quite encouraging. You can see for 23.4% the overall Improvement in indirect path is marginal. That is 30% up to 30% Then up to 50% is 13% paths then the Double reduction in latency is for 23% of the paths. This is a significant improvement So it means the overall argument that overlay networking results into better Utilization in terms of throughput and latency Is found to be correct now This is I just wanted to share with you that look at it again and you can make Even more interesting insights