Know How... 114 (Transcript)
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On this episode of Know How we are going deep into feedback, Aaron Newcomb is dropping by to give us more Linux tips and we are going to teach you the secrets of flight.
Father Robert Ballecer: Welcome to Know How. It’s the twit show where we build, bend, break and upgrade. I’m Father Robert Ballecer.
Bryan Burnett: And I’m Bryan Burnett.
Fr. Robert: For the next 50 minutes we are going to be letting you into some of the projects that we’ve been working on over the last few weeks so that you can go home and geek out on your own time.
Bryan: Right. And so the article this week that you picked up on was a little computer kit.
Fr. Robert: Yeah. It was a cool idea. It was a kickstarter. They tried to get $100,000 and they ended up getting 1.5 million. Which was awesome! The idea is the Kano is a computer that you make yourself. It’s a great idea. You get this little kit. You build it with your kids. They learn about computers and they learn about programming. Because the Kano operating system was designed to teach. Nice idea.
Bryan: It looks like a very nice package. Everything is put together really well. The graphics on the website are definitely well put together.
Fr. Robert: I do not want to crap on anyone’s idea. I think this is a good idea because you can get someone, who wouldn’t otherwise build a computer, to get interested. This is great. I have one issue. This is just a Raspberry Pi.
Bryan: A Rasp Pi with a few accessories and a price tag of $150.00?
Fr. Robert: $150.00 right. So it has a Rasp Pi just like this. $40 for this. It has the memory card with the Kano operating system that is $5.
Bryan: You can’t just download the operating system?
Fr. Robert: You could. It’s just a Linux Distro that they customize with their graphics and their branding. It’s got a case, which might run you another $5. It’s got another wireless keyboard and mouse which is another $10 or so. It’s got a wifi dongo which you can get for $4. So, all in all it is maybe $70 worth of parts?
Bryan: And selling for $150? There’s quite a bit of profit margin there. For packaging I guess.
Fr. Robert: Again, the fact that they are encouraging people to build their first computer. That is cool. It is a really underpowered computer.
Bryan: I love the Rasp Pi and I’ve done a lot of fun projects with it. But it’s not going to be your one PC that you do your everything with. I guess it could be your first PC if you are a kid building it, which is who they are trying to target. It is just so packaged and put together.
Fr. Robert: That is the problem I have with it. I think it is a good idea, I still think the people who bought it will have fun. But they bill it as your kid will build the computer. You don’t build a Rasp Pi. You are attaching power, networking and HDMI. That is it. And everything else is preloaded. So it’s building in the sense that you build your game console by plugging it in.
Bryan: So then then the next step you did was that you pieced together some parts for around the same price but different specs.
Fr. Robert: I wanted to know that if I am going to poo-poo this idea and say this is so expensive, could I do something for $150? What could you actually build - if you really wanted your kid to have the experience of actually building a computer what would a complete kit cost? So I did a few things. I started with this. This is a MSI, this is an AM1. This thing will run you about $30. And then you’ve got the AMD Sempron CPU, this one is about $31. You are looking at $61 for the motherboard and CPU. This is actually pretty capable, this will run Windows decently. It will do all the browsing and it is actually expandable which is kind of nice. For the memory I was looking at some Exterra sticks that I found. You can get 2 GB for about $20. That is not a stretch. I couldn’t get the SSD’s but I was able to get a 500 GB Western Digital Scorpio with a 2.5 inch drive for about $21. Adding the keyboard and the mouse and eight case with a power supply adds another $37-$40. So all in all, the parts that I bought cost exactly $150. And that gives you a computer that you actually have to build, it gives you a hard drive, and optical drive, so that you can install a Linux Distro, it gives you much more capable machine and your kid will actually know what the parts are when he is done.
Bryan: The thing I like about going the route that you did is that it gives you a little bit more flexibility with some of the parts that you got. But you have a ton of stuff laying around. So really, buying the kit is not for me because everything looks pretty together doesn’t mean I want to spend the extra money for it.
Fr. Robert: Right. And like you said, as you start building miss you are going to start saying wait I can do 2 GB for $20 or I can do 4 GB for $30. I could spend an extra six dollars on the CPU and get one that is 30% faster. I could maybe go with an SSD and make this a screaming machine for $30 more. It is infinitely upgradable but then you start getting into the range where for about $220 you can buy a pre-bundled Dell machine with Windows and everything. What you are looking for is that educational machine. I do believe the Kano does have merit.
Bryan: Obviously it is popular. It got way beyond its kick starter for what they set for it. But it is not for me.
Fr. Robert: May be if you got a nephew or a niece, son or daughter, someone who you thought might want to learn about this…
Bryan: And just give it to them and see where they go with it?
Fr. Robert: Exactly.
Bryan: This would definitely be a project that you would have to help someone who doesn’t know much about computers. You would have to be the one that gives the parts together and everything.
Fr. Robert: But at the end you actually have built a computer. Truly. Versus just plugged it in and made sure that the power turned on. They will probably have to troubleshoot it a little bit because something will work the first time, but the cost is low enough where you could let them make a couple of mistakes you know how a computer works? Even if you never do Hitter hit is built to enter lamp stand all of the parts. Now when we come back we want to show you a little bit of feedback. We've had some really good questions in our Google plus community. It has been an active community the last few weeks.
Bryan: It is really exciting to see all the projects the people do in there and stuff.
Fr. Robert: Exactly. And that is what we want to show off. We want to show off some of the things that people have asked, some of the projects that people have been working on. But before that we want to thank the first sponsor of know how. And it is Harry’s. You need a good shave and we know that you need a good shave so you should be looking for a premium product. And that is exactly what you get with Harry’s. Shaming isn’t fun. Sometimes we cut or scrape ourselves with dull blades and razors are expensive. They can run about four dollars, five dollars or six dollars a blade. And if you've ever done that kind of sad lonely walk into the supermarket aisle and the blades are locked behind the case? Why do that to yourself. Why not just get yourself a great shave from Harry’s. This is the company that is fixing all the shaving stuff. They make the razors in their own factory in Germany. The engineer them for short performance. And they ship them for free to your front door. And because they make and ship their own blades, Harry is a more efficient company which means they can give us their factory direct pricing. And they guarantee your satisfaction. In each kit you get a razor with a handle the looks and feels great, three razor blades, and a foaming shave gel which is just so smooth and it’s got that nice sent to it. I have been using Harry’s for a while. Ever since they sent me my premium shave kit this thing has been living in my home. It is what I shave with. You know how shaming becomes a ritual after a while? If you are going to have that experience why not use something that is nice. That looks good and feels good. I just has the right weight. That is definitely Harry’s. What we want you to do is we want you to see if maybe Harry’s is what you need. What you want for your shaming ritual.
Bryan: I don’t shave often but when I do I use the kit. And it’s nice. I allow myself about an hour.
Fr. Robert: Folks let me take you something right now. If we get enough of you going to Harry’s we will make Bryan shave on the set. It’s a good idea right? How about this? We will make you shave half your beard. There you have it folks. Go to Harry’s and Bryan will shave half of his face. Now if you are convinced that you want to try carries in your personal grooming technique and habit in your kit, why not try our special offer period go to Harrys.com and get five dollars off your first purchase with the code know-how. And enter the code know how at check out. We thank Harry’s for their support of Know How.
Fr. Robert: Let’s get into the feedback. We’ve had some decent questions in our Google plus community. The first one was actually sent to us by a user by the name of Yanni H from Amsterdam. He wrote that “In several episodes you have talked about tapping networks in order to slurp packets without users knowing about it. I know you showed us several very inexpensive devices that can tap copper lines without changing the characteristics of the electrical signals flowing through a network, but what about new networks? Most new networks are switching to fiber. Is there anything that they can do something similar on those new networks?” Well ,Yanni. this is a very good question. What he is talking about are the devices like this. This is a net optics That we have been playing with. It is an aggregating So it allows us to have ended out, the pastor. We can take the receiving traffic and the sending traffic and we can either take them singly or we can aggregate them together so that I can get them both on my computer in one stream. Very cool, but that is how it has been working for copper. Copper is usually easier to tap just because I’m dealing with electrical pulses and we know really well how those characteristics of the electrical pulses work. It’s a lot more common and there are a lot more devices that work with copper. I could use a have as a cheap tap. Or I can make myself a really crazy like $1.50 cheap tap. Using category five cable. It would be a tap. He has a good question. How do we do it with fiber?
Bryan: I’m wondering this must be like a home network with fiber?
Fr. Robert: It could be. Some of the newer home networks come with fiber or it could be one of those networks that maybe you have any enterprise class network with fiber to the home. Or it may be you are planning some nefarious stuff.
Bryan: Or maybe he is an enterprise guy and…
Fr. Robert: And he just wants to know. And actually the answer is yes. This is actually a fiber. It looks a lot smaller because it is actually not that complicated. And just like the copper tap I've got a way to have an input and output so that I can tap either the sending or the receiving. Remember fiber has two pairs. There is a send strand and a receive strand. But if you look inside this thing it is actually a super simple device. There is actually no electronics in a real fiber. It is actually easier to tap fiber once you know how it works. This is essentially a loop that goes from here to here. It is nothing. And then they slightly bend that fiber just so it deflects enough of the light outside that it can be picked up by another strand of fiber. So you are just siphoning off a couple of those protons.
Bryan: You are splitting the actual fiber and getting just a little bit of the light coming out?
Fr. Robert: That is all it is. And the nice thing about this is that there is no latency. There is no equipment to slow it down. They don’t have to forward the packets, they don’t have to worry about whether or not they are degrading the signal.
Bryan: Is a pretty affordable to?
Fr. Robert: This one was about $1000. remember these are high in devices. The thing is, this is $1000 but I actually have done it in my lab just using a fiber splitter. Any patching kit. What you do is you scrape off some of the fiber and then you can put it close enough to another pair of fiber and when you start to get a little bit of light, just enough that you can register it on the tap of your computer you epoxy the whole thing down. And it is a mess because it is not clean. You can do it do it but got up to five dollars. It is a huge amount of trial and error. And you do have to know what you are doing. Because believe it or not with the fiber strands that I worked with, if you push it against your skin it will go through your finger. It is really, really sharp.
Bryan: We’ve had fiber going through the computers in the edit machines and it is something Alex always tells me don’t touch the end of the cable. But I do it anyway.
Fr. Robert: This one is expensive because it is actually a 10 Gb version. That is why it is crazy expensive. You can also find one gigabit versions of this for quite a bit less. I would probably make my own. If I didn’t have a ready supply of these.
Bryan: So there is a way to tap your fiber. The end areas and expensive way and then there is the do-it-yourself way that could be time-consuming but it exists.
Fr. Robert: What I tell people is that if you want to practice there is a super easy way to do it. What you want to do is toss link, the optical out of a lot of devices? that is just an LED light so it is safe, it is not going to hurt anybody and you can practice your technique. Scrape off the clotting so that you get enough of the light coming out of the side, get another toss link cable, snip it and try to get it close enough that you actually get a signal on a second device.
Bryan: It seems so strange that that would work.
Fr. Robert: It seems so strange that it would work and the first time it happens you’re like no way! That’s not possible! Try it out. That is super cheap and it is really easy to do and those toss link cables are not expensive and they are not going to hurt you. Everyone probably has an optical device.
Bryan: Cool. I had no idea that you could do that.
Fr. Robert: There you go. Let’s go to the second question. This is actually something that popped up after our episode last week.
Bryan: This is an ongoing discussion we’ve had during the whole course of building the PC.
Fr. Robert: It always pops up in the chat room, Did you try hybrid? Hey, did you try Hybrid? So we want to give them their due. We kind of poo-pooed hybrid drives and said unless you’ve got a single bay laptop, I wouldn’t use it. It is a compromise.
Bryan: Not as cheap as a spinning platter but not as fast as an SSD.
Fr. Robert: Hybrids are great. I’ve been using them a lot. This is one of the first ones they released.
Bryan: They feel like a stop gap between when SSD’s were super expensive, which the price just continues to come down.
Fr. Robert: When these first came out like 2 1/2 years ago or so, they were actually great for what they were. Because they gave you better than hard drive speed but they didn’t cost you ridiculous amount of money that an SSD would cost to you. For example the very first one that I ever tested, the first SSD, was a Samsung 470 series. A very nice device, very fast. Did 255 mb per second read and 250 write, but this thing would cost you like $300. Versus at the time there was this SeaGate Momentus ST hybrid drive which would cost you $110. There was a performance gain, maybe half to 60% what the SSD could give you. But it was four times the capacity and was 1/3 of the price. So it totally made sense. Especially if you had a one bay laptop drive. I think maybe we should talk about what hybrid technology actually is. There is a light of misunderstanding about how it works. When we talk about a hybrid drive, there are actually two different types of technology that people associate with hybrid. Both of them centered around this idea of combining spending storage with a flash memory, NAS. Solid state memory. Very fast. Now in one case you have this. This is called an SSHD. This is a solid-state hybrid drive. In a single package you've got the spinning drive and you’ve got the memory. In this case there is 8 GB. Some have 16, some have 8. I heard rumor there was a 32 but I have not seen it. But To the outside computer it just looks like a drive. It is a single device. Which is kind of cool because then it is always agnostic. You can use it on Linux, Mac OSX, you can use it on Windows. All it knows is that it sees a hard drive and that hard drive seems to be pretty fast. There is another way to do this and that is to combine something like this. This is a standard rotating hard drive with something like this. This is an MSATA SSD. The idea is that this little device here is actually an SSD. This is a 24 GB SSD. And this plugs into the motherboard. so you have two individual devices that actually work together. The operating system can see both of them. But it knows I’m using that smaller SSD to cache the hard drive. It is kind of popular just because you can typically get a hold up more SSD. You can get these in pretty decent sizes. Which means the more cache you have, the more performance took it out of it. Because the wavelength hybrid hybrid drive drivers work is that if it came to England with her again in that 16 gb of cache.
Bryan: Then it will be accessed very quickly. But if it’s not, it has to go to the rotating platter to retrieve the information and so you lose performance.
Fr. Robert: They do a pretty good job of optimizing what is in there. They look at the data blocks that get loaded the most. It is smart.
Bryan: It prioritizes the things that get loaded a lot. Were things that would typically need to be loaded faster?
Fr. Robert: Exactly. Like operating system files that get called to on a whole heckuva lot. So when you are accessing the flash part of the drive it is crazy fast. It is ridiculously fast. And it is much less expensive. But the problem is once that cache runs out you go back to the drive..
Bryan: And it’s just like you are using a regular hard drive.
Fr. Robert: Right. Which is not great. Now there were people in the room who were saying you don’t understand. Let’s go ahead and read the question. He actually made a really good point here. “240 GB SSD is roughly $125, add on a TB of spinning drive to that for about $70 and you are sitting at nearly $200 for that configuration. By contrast you could pick up a 1 TB, 3.5” hybrid drive for about $105. Double the cost doesn’t seem like a tidy bit more expensive. SSD prices are dropping but they’re not even close to competitive with spending drives yet. And for those of us that need the space, hybrids are a valid option even any desktop.” Now this is where I disagree. If you've got the desktop and if you’ve got the next two slot I see you are crazy to go with a hybrid drive. And let me explain it. A fast hybrid drive like the latest version includes 16 GB of cache. That will get you about 110 MB per second of read and about 80 MB per second of write, which is decent. Right? But go ahead and take something like a modern SSD like this, the Kingston KC300 that I like so much. This will do about 520 MB per second of read and 500 MB per second of write. So it’s not just a little faster, it destroys it.
Bryan: It’s like a prop airplane versus a jet.
Fr. Robert: So you're not just talking about a little speed difference you are talking about a huge speed difference. Now that didn't matter when we were dealing with these kinds of drives. Because these would run at 200+ megabytes per second and even then the system itself wasn’t really fast enough to take advantage of it.
Bryan: Right. Because you have to have the motherboard, hardware and everything to be able to even transfer speeds like that.
Fr. Robert: But if you’ve got a lot of storage, not only does it mean you are probably doing something very serious with your computer, which means that you probably got a decent CPU, a decent motherboard, a decent GPU and you are starting it if you are not feeding it enough storage. And so, you are talking about one quarter the speed but the cost isn’t that great. Let’s take a 4 TB setup. I would go with an inexpensive SSD, probably like a 120 GB, that is the low price. So 120 GB SSD you can find for about $60. That will give you 400 MB per second read and 400 MB per second write. You can find a 4 TB hard drive for about $130 which that is a lot of space. $170 for the two of them. A 4 TB SSHD with 8 GB of cache on it will cost you $170, which means if you look at it… we are sacrificing 80% of our performance for about $20? That just doesn’t make sense. And even if I was using my single bay laptop I would still be reluctant. I gave that is one of the reasons why you would use it, but I would be reluctant if I had a USB three or a thunderbolt because both of those interfaces are actually faster than a hard drive. So I would get the crazy fast SSD and the laptop and then plug-in the next terminal storage for my storage.
Bryan: And typically when you have that much storage light may be large video files and stuff that doesn’t necessarily need to be loaded up quick like an OS.
Fr. Robert: So, is there a place for Hybrid drives? I think there is. I think people brought up some really good points on when you would use it.
Bryan: And for the cost versus performance it is not worth it.
Fr. Robert: It’s really not. We talked about 20% were actually 11% increase in cost for an 80% decrease of performance. But if you looked at it in the cost of the entire system, like that Toshiba W50 that we played with. You are talking about a 59% performance penalty for a 3% increase in cost? No. Don’t do that.
Bryan: The numbers just don’t work.
Fr. Robert: At crunched the numbers.
Bryan: At least now I have a better understanding of how hybrid drives work. I understood there was an SSD and a spending drive inside of them that now it is a little bit more clear. Once you've had an SSD, they are more expensive but once you’ve used one it is hard to go back.
Fr. Robert: And use it the way that we use it. We’ve got the SSD and we’ve got the monster drive. When we are doing a video editing project you move it onto the SSD and when you’re done you move it off.
Bryan: At home I have my 3 TB drive, but on my laptop I have a 256 really fast SSD. I don’t have any big files on my laptop.
Fr. Robert: So folks this is not in your face. There is a place for everything. At some point we are going to promise you that we will do a comparison between a rotating drive, a hyperdrive, and an SSD. Just so you can see for yourself the kind of performance benefits that you get from that particular technology.
Bryan: Will do like the price versus the capacities versus the performance.
Fr. Robert: And we’ll do both the integrated SSHD and the hybrid dual drive system. We’ll do it all because you deserve that information.
Bryan: The nice thing is that there are a lot of choices out there and it really probably comes down to what kind of PC do you want to build? If you Are doing a gaming PC you are already probably spending about $1000 so you probably want an SSD in it. If you are disappointed have a PC like the kit you were talking about that you were building for $150 for somebody’s first computer, then a hybrid drive. It’s not going to be a big deal for them.
Fr. Robert: Folks, it’s all about giving you the knowledge. By the way, speaking of knowledge. Did you know there is a place online where you can get knowledge to dump in your knowledge hole?
Bryan: My knowledge hole has been filled to a certain extent but I want to refine, I want to level it off.
Fr. Robert: You’ve got a couple of peaks and valleys that you want to fill. You kind of want to make it level.
Bryan: It’s more like a knowledge pothole. Not on the knowledge freeway? I use lynda.
Bryan: We are switching over to premiere and so I’ve been doing a couple of outside projects to kind of practice it and some of the things that I do on Final Cut seem really easy but I don't know how to do it in premier. But fortunately Lynda has all that stuff stacked out.
Fr. Robert: Exactly. I think that is what makes Lynda so valuable. It is a place to learn for the first time. For example If you wanted to learn about go pro and using go pro in quad copters. Lynda Is a great place to go because they’ve got courses that will take you from step one to step eight. They will show you how to mount it, what kind of footage you will get, how you should edit it. That is really the strength of that sort of begin her knowledge. But they also do this indexing. This wonderful indexing which allows me to pull up an answer. Let’s say I’ve been using premiere for 12 years…
Bryan: And there's a few things I don’t remember how to do and I want to brush up.
Fr. Robert: Right. And that is what Lynda lets you do. It lets you go to what you need at the time, be it at the beginning lesson or an intermediate lesson or an expert lesson. Now, it’s your one-stop shop for knowledge. It is a repository for all things awesome. They are an easy and affordable way to help you learn. You can instantly stream thousands of courses created by experts on software, web development, graphic design, and more. They work directly with industry experts in software companies to provide you timely training, often on the same day of the new version releases. So that you always stay up to date with the latest and the greatest of the tools that you have to use each and every day. Now all their courses are produced at the highest quality. Not like the homemade videos on YouTube, which I love because that is where I come from, but sometimes you want to get all that bad lighting, the bad audio out of the way and just pay attention to the knowledge. We are all about the knowledge folks and sometimes you just want to concentrate on the things that are important to you. Now the tools as I mentioned include those searchable transcript so that you can use it as a reference when you need an answer to one little nagging problem that just doesn’t seem to go away. So whether you are a beginner, or advanced they have a course for your experience level. You get to learn while you are on the go with a app for the iPhone, the iPad or Android and they have one low monthly price of $25. Which gives you unlimited access to over 100,000 video tutorials. A premium member with an annual plan can download courses to their iPhone, their iPads or their androids and watch them off-line. That gives you the ultimate reference tool. If you are out in the field and you don’t have a connection, have those lessons downloaded to your device so you can recall them if your field stripping a go Pro off of a quad copter or if you are in the field and you need to know more about the lessons that you took on data management in a data center. It is all there if you become a premium member. They have also got courses on iOS eight so if you want to know all the features, all the tricks and be up to date with the latest and greatest from Apple they will give you that. Or they will give you simple android development tools. They will give you Monday productivity pointers, and songwriting tips and logic Pro. For any software that you rely on can help you stay current with all software updates and learn the ends and outs to be more efficient and productive. We’ve got a special offer for you. You can access all the courses free for seven days. Completely free. Visit to try free for seven days. We thank Lynda for their support of Know How.
Bryan: I’m really looking forward to using the quad copter stuff that we are going to be doing. At least I can fill and assured I have looked up enough stuff on it.
Fr. Robert: Crashing won’t be from lack of knowledge. We are going to start talking about that we. First, your friend and my mine…
Bryan: Aaron Newcomb our resident Linux… nice guy, super smart, comes all the way up here and does these Linux tips for us. I’m definitely a graphic user interface kind of guy. The terminal has been kind of a mystery to me. But Aaron came in, gave me a few commands to help me get by.
Aaron Newcomb: Everybody, Aaron Newcomb here again for another Linux tutorial. Hopefully you have been getting some useful information out of these if you are a beginner or new to Linux. That is what we are shooting for here. Right now, just to recap, we’ve got our desk stop set up and installed. It is working great. We have installed some new software so we know where everything is, we know where the browser is and all that great stuff. Pretty much this is your standard desktop environment. You should be able to play around with it and get familiar with it. But, we need to do a little bit of deeper dive before we go forward with any more tutorials. And the reason is because we need to talk about the terminal window or the terminal. This is typically represented by a little box down here on the task bar or it might actually be in the menu under accessories. That is where it usually is. Sometimes you can find it right over here so it is really easy to find. Pretty much everywhere. And the reason it is so easy to find is because it is so useful. The first thing you’ll see is that you have your name and the name of the computer presented to you along with what is called the prompt. That is the little $here and when you type the words will go right next to the prompt. So if I type in a command that is where the words appear and that is normal. You can see that it prints out a listing of the files that I have in this current directory. So it is as simple as that. You type in the command, press enter. Very simple stuff. Now, some of the shortcuts and things that you will want to know about the terminal as you get started. If you use the up arrow on your keyboard that will cycle through the list of commands that you have used most recently. Terminals keep a command history for the very simple reason that you reuse commands a lot. All of these commands that you have previously used are in the history. It is a good thing to know because it makes it really simple to access those commands so you don’t have to type them in from scratch. Another really useful command that took me a wild to find out is that if you press control R, that will bring up this thing called reverse I search. Basically all you need to do here is start typing the first part of the command that you want to search for. You are searching through your command history. You will see that it will pull up whatever the most recent or closest match from my recent history. You can backspace and type in a different command. Then, what you can do is you can continue to press control R and it will cycle through the commands that you have typed. It will just do this sort of circular fashion until it gets back to the beginning. Once you have gotten the command you want you can hit enter and it will run that command. That is really good to know. The other really good thing to know is that as you are typing a command sometimes you may not remember the full name of the command. And sometimes you may not know how to spell a certain command. Sometimes things are a little wonky in Linux. Lets say I don’t remember the command I want to use. It is apt - something. So you can hit apt twice and it will show a list of commands that start with apt. These three things can be really helpful in getting you set up in getting you going right away. All right, let’s talk about one of the basic commands you were going to need to know in order to feel comfortable on the command line. The first one, and maybe the most important one, is a command called man. And why this is important is because it stands for manual. This was something that was actually built-in early on in the early days of Unix, before Linux. this was developed by people like Dennis Ritchie and some of the very first people to develop Unix because they knew that they needed a instruction manual for the various programs. They needed to document the instructions for various programs that they were developing and they didn’t have a way to do it. So they came up with a way. It is called Manual. Or the command man. So, if you want to know what a command does, in this case lets start with LS. But if you wanted to know what the command LS does then you would type in man LS. That is going to bring up a man page. This is what the man page looks like. It is going to give you a ton of information on how to use the command, what all the options are, and how to structure the command. In this case it is LS and then the options and then you can include the name of a file. It tells you how to structure a command on the command line, what all the switches does, if you press space it will page down and you can find all sorts of information about this command and what all the options are. A lot of these commands have a ton of options. So there is no way we can cover all those options in a tutorial like this. So it is really helpful to know that you always have the man page at your disposal. To go look up more information about these commands. That is the first one. The second one we have already talked about is LS, that is a directory listing or file system listing. As we did before press LS and press enter. That gives you a list of all the files I have in the directory where I am. How do I know what directory I’m in? There is a command for that and it is called PWD. PWD Will tell me where I am at in the file system where logically. You can see I am in the directory of Home Newcomb. That is my home directory. When I typed LS it gave me a listing of all those things that are in my home directory. If I type in LS - L that is going to give me a little bit more verbose readout of the things that are in my home directory. There are a lot of things listed. All the properties about my files, in this case their own directories. But lots of things about those files. We won’t go into the details on that but it is good to know. Now you can also do an LS on some other location. LS/etsy. This is where a lot of configuration files are stored. You can see there is a lot more information in there. But it doesn’t really matter where you are on the system you can do LS and in the location where you want to get that listing from. So if you’re familiar with Windows back in the old days there was a command line called DIR for directory. That is a similar command to LS. As with everything on Linux, LS is more capable than the directory command was on Windows. Okay let’s talk about some more. What if I wanted to change my directory or change where I am at? We mentioned before PWD will tell you where you are at, what if I want to go to a different place in the file system? What if I wanted to go to the Etsy directory because I want to do some things there? That command you would use is CD for change directory. Now I’m in Etsy and you can see in my prompt down here it actually tells me where I’m at. If I ever forget I can look at that. Or I just type in PWD and it will tell me exactly where I’m at. If you want to go back to your home directory here is another cool shortcut I will teach you. You can do CD tild/. Type that in and now I am back in my home directly. Okay let’s keep going. Another useful thing to know especially when you are working in the command line is how to copy and paste. And how to move things around based on where you are at. So, I am going to create a file called cool file. If I do an LS you’ll see that I have a file here in my directory now called Cool File. It basically just creates an empty file with nothing in it. Let’s say that I want to make a copy of that file and call it something different. I could use the CP command. CP and then I could type in the file I want to copy. Notice I am just going to type the first little bit and hit tab and that completes, based on what is there. CP Cool File. I’m going to call it Not Cool File. So this is going to copy the Cool File into a new file. When I hit enter it has done that and I can do an LS and see that I have two files now. Pretty cool. Or not cool. That is how the CP command works. Another when you’re going to need to know is how to move a file from one place to another. Not just make a copy but actually move it. That is done with the command MV for move. We are going to have the same structure so we are going to move Not Cool File and we are going to move that into the Etsy directory. We use forward slash for a space in between characters instead of a back slash. So we are going to move that into Etsy. Uh-oh, can’t do it. The reason why is because that Etsy directory is protected. Because there are a lot of configuration files in there. So how do we overcome that issue? There is a command called SUDO. And that gives you special permissions to act as the root user. In the windows world you would call this an administrator. In Linux We don’t have an administrator but we do have a root user that has special permissions to do basically anything on the system. So you can really screw things up. You have to be really careful. In this case we are just moving an empty file around and we know that it is not going to hurt anything. So in this case we will do SUDO and then we can use that same command. Or we can just hit the up arrow and go to the beginning and do SUDO, hit enter, enter your password, and hopefully it has moved that file where we wanted it to go. Let’s do an LS where we are at. Not Cool File is right there. It moved it over there. I know we are arming you with a lot of information today but these are basic things you need to know to get going.
Bryan: Cool. Thanks for that,
Aaron. And Padre, what would you say that
you took away with that?
Fr. Robert: I am root.
Bryan: Again, thanks Aaron. When he came in and showed me some of that stuff it gave me and now of a foundation that I was able to extract a package that I had downloaded. So I feel like I am gradually moving along. Those are just some of the basics and he mentioned once you get the hang of it you do feel like you are is superhuman going through just doing command line stuff.
Fr. Robert: I think both of us are in the same place with Linux. We both use it. We both have it on several devices. But both of us do the whole thing where if we messed something up, it is easy for us to say it'll take me 20 minutes to reinstall and put everything back rather than just figure out what I did.
Bryan: When I was installing Ubuntu on my virtual machine on my laptop I screwed up the resolution. I don’t know how, it was easier for me to just reinstall it and then it fixed it.
Fr. Robert: These are the lessons. Especially the command line stuff. These are the lessons that will let you start poking around and saying oh that is where that setting is kept. That is what I have to do to fix this. That is what I have to do. For example any time on the Rasp Pi I got used to whenever it was testing new network adapters just to reinstall rather than try to figure out what I have to change and what package I have two install. Once you figure this out, you don’t have to do that anymore.
Bryan: In for a long time when I was doing a Rasp Pi project where I was doing the game, then game machine. It is a lot of just going through forms and copying commands, but it wasn’t like I had a full understanding of what all the commands meant. And having Aaron come in and explain some of that I understand the directory system better, I know how to navigate to certain files and where to go to find them and stuff.
Fr. Robert: Normal people shouldn’t use Linux!
Bryan: I don’t think any normal people use Linux.
Fr. Robert: Normal people can use Linux. Linux is understandable. You just have to de-mystify a lot of it.
Bryan: The fascinating thing about Linux is how deep you can dive. You can spend your entire life, it feels like trying to understand it. But the more you understand, the cooler it is and we are all about knowing things and bringing out experts to explain it to us.
Fr. Robert: We are going on to our segment now about flight. We have to clear up a few things before we get into our quad copter. We are going to test your knowledge in a bit. But first Alex showed us this during the break. If you like SSD’s, you are going to love his new system that he and Russell have been working on, a brand new production system for Twit. It Involves these cards that have 350 Mb per second read and write so they are slower speed but these are Enterprise class so they last a lot longer which is what you need when you are emptying and completely filling the SSD’s.
Bryan: They don’t feel real. I don’t know how to explain it but this feels empty.
Fr. Robert: I think that is the same idea because they plug it into the injection system and there is a little red light, then the light turns green. When the light is green… the card is clean! we are actually going to give you a behind the scenes look. I have found that the system they are building is absolutely fascinating.
Bryan: It is a one-of-a-kind thing.
Fr. Robert: It really is. We are building something that other people will duplicate at some point. We are going to show you how we are using SSD’s for every bit of content that will be flowing through the Twit Brickhouse.
Alex: The 350 mg per second is the bottle neck of transfer speed.
Fr. Robert: This becomes the slow part. Which is ridiculous because if we used hybrid drives we’d be here forever.
Alex: We use a 10 GB ethernet for the transfer but it is pulling off that drive which is 350 mb a second.
Bryan: You are going to be playing around with that for a while.
Fr. Robert: Okay, let’s go ahead and talk about flight for a little while. Bryan you mentioned that you learned everything you needed to know, about how things work and why they work and why planes stay in the air. What did you learn?
Bryan: I learned air going over the top of the weeding is moving at a…. I’m drawing a blank. It is Bernoulli’s principle. Faster over the top and slower underneath which creates lift.
Fr. Robert: Which happens because as the wing moves through a volume of air is split second. Those two volumes that it has created….
Bryan: They come together at the end.
Fr. Robert: Exactly. This is what high school kids were talking about flight.
Bryan: I’ve seen the graphics. There are little circles going underneath and the exes go over the top and they connect at the bottom.
Fr. Robert: But this is actually showing us something that we shouldn’t be saying. In a bid they are going to break up this air flow and do spurts of smoke over this waiting so that you can see exactly what has been happening. As you said, most kids were taught that as a wing goes through the air it divides the volume so that you got air going over the top and air going over the bottom. They have to get to the end of the week, the trailing edge of the week, at the same time. Which means that the volume over the top is going faster than the volume over the bottom because it has further to travel. But if you look at this, it is totally not true. That doesn’t happen at all.
Bryan: The angle of the tack on the front of the wing splits the air forcing it underneath which then pushes it up.
Fr. Robert: It forces a volume underneath any volume over the top but notice how much faster the volume over the top gives to the trailing edge of the wing. They do not rejoin at the trailing edge. It is not disproving Bernoulli’s principle. Bernoulli’s principle is part of flight.
Bryan: It is just redefining the way you think about flight.
Fr. Robert: most of us have been taught that Bernoulli’s principle is the thing that causes left. Because the area is going faster over the top of the wing it creates lower pressure and that lower pressure sucks the week of and therefore sucks the plane up into the air. It sounds good. It helps to visualize. But it is not exactly what is happening.
Bryan: What are these birding flying around for all the time?
Fr. Robert: They are flying around because of Newton’s second and third laws of motion.
Bryan: So for every action there is an opposite and equal reaction?
Fr. Robert: That is one of them. Newton’s second law of motion Tells us that for every force that is being inserted depends on how much mass and how much you are accelerating. Newton’s third law is the one that tells us that for every emotion there is an equal and opposite reaction. Second and third laws are actually what keeps the plane up in the air. As a plane is going through, as a weed in dividing the volume of air, yes there is more pressure on the top but the primary force of lived is the air that you are redirecting. As you direct volumes of air down it is going to create a force that pushes you up. The faster you do that, and the more air you push, the more force you get up. The end result is that it will create a high pressure area below the wing and a low-pressure area above the wing. Bernoulli’s principle is still valid But for kids who were taught to believe that is the only thing holding an airplane in the sky it is just not true. The reason we are telling you this now is because we are going to need to know this as we move into designing our quad copter. On this particular plane, these control surfaces allow me to direct air in different directions. So I can make it go up and down on the back of the wing which will force the plane. This will make it go left and right. So all I'm doing is deflecting air. That volume gets deflected this way and the plane will turn this way, if I go this so that it’s down the tail kits pushed up. If it’s up, the plank is pushed down. The reason why I am showing you this is, think about a quad copter.
Bryan: A quad copter doesn’t have wings. How does it turn?
Fr. Robert: Not only does a quad copter not have wings, but it doesn’t have a rudder. All it has are these four propellers. It is important to know about lift because these four propellers are actually creating lift. It is holding the squad copter up because of Newton’s second and third law. The shape and angle of those propellers is what allows it to generate thrust. What we are going to learn in the next episode is we are going to learn exactly how it works on a quad copter. How it uses the bearing thrust of the propellers in order to create the directional force that it needs to be able to fly properly.
Bryan: Because it is all software.
Fr. Robert: It is all software. Unlike a plane, where if I push this way and it pushes the servo this way there is a direct linkage. In a quad copter it is all fly by wire. When I give it impolite, the computer on board as to say he wants to go forward or he wants to bank left or he wants to band right and it has to adjust the thrust to each propeller accordingly.
Bryan: Which is fascinating considering how small these are getting. And how maneuverable they are. These are set up like a helicopter propeller but unlike a helicopter which would have a propellor on the back, the tail rotor which helps it do side to side stuff this doesn’t have it.
Fr. Robert: Because that is rotational energy. This is also Newton’s third law. If the propellor is moving this way, the body wants to move the other way. On a helicopter it has that tail rotor to cancel out that force. There is no tail rotor here so we have to figure how this works. Now we are going to be doing this over the next 12 or so weeks. We are not going to go complete we are going to put a couple breaks in there because people are going to get hired a quad copters. And we are also making sure there is plenty of other material matters going to go into Know How. But what we want to do is we want to show you how you can go from basic frames and motors and remote controls into building your own quad copter. We are going to give you a couple of different classes that you can build, a couple of different cost that you can build. From $50 all the way up to like $3000. Depending on what you want to build and what you wanted to be able to do. Starting next week, it is quad copter baby. Are you excited?
Bryan: I’m very excited. The more I learn about how they work, the more I want to build one.
Fr. Robert: We are going to give you a complete part list of everything that we bought. But we want to give it to you at the beginning because we know there is going to be a few of you who are going to want to buy some of your parts and play along. We will make sure that you have that ahead of time. For the rest of you, just watch it. Because we are going to give you a couple different options including something like this. A super inexpensive way for you to learn how to fly a quad copter before you decide whether or not you actually want to sink a lot of money into it.
Bryan: Inexpensive and impressive.
Fr. Robert: We know that this has been a lot of material for this episode of no help. Everything from the feedback to Aaron’s segment on Linux to our quick introduction on flight and the project list for the quad copter. But we don’t want you to have to watch this over. Instead what do we do?
Bryan: We will have them curated on twit.tv/kh.
Fr. Robert: GO there for our show notes and why not download some of the episodes that will help us on our projects? In fact go ahead and look at project lunchbox because a lot of those same principles are going to transfer over to building a quad copter.
Bryan: It will help you get started with the whole remote control world and everything like that. Don’t forget to subscribe. Download the HD version.
Fr. Robert: We do a lot of notes. Don’t forget that you can also find us on Google Plus. It is 7600 members strong.
Bryan: It is close to 8000. A lot of good stuff being posted in there, a lot of good questions being asked, and before we are able to answer them a lot of people hop in.
Fr. Robert: It used to be that I had to jump in there once in a while but now…
Bryan: It is its own community now. Just people who like building stuff.
Fr. Robert: They like the knowledge. Also you can find us on Twitter. You can find me @Padre SJ.
Bryan: And I’m @cranky_hippo.
Fr. Robert: And don’t forget our TD, Alex Gumble @anelf3. Follow him to find out what is going on behind the control desk. Know How is a crazy place. Until next time, I’m Father Robert Ballecer.
Bryan: And I’m Bryan Burnett.
Fr. Robert: And now that you know…
Bryan: Go do it!