So let's talk about servers. Specifically this Dell R720XD. There are a lot of companies that live on the bleeding edge which means they change out their servers rather quickly and before they're technically end of life but that's obviously a matter of opinion. If you need the fastest best servers all the time you're willing to swap them out even on a yearly basis. And I've seen this in the financial markets especially where every tiny millisecond can make a lot of money for them. Therefore swapping out servers becomes worth it because they need the absolute bleeding edge all the time. That opens up the secondary market to a lot of great deals on used servers. And the folks at TechSupplyDirect, someone we've done some business with, decided hey they'd like to sponsor our channel so they made an offer code.  Specifically what we're going to talk about today is this Dell R720. And I'm making this video also because I'm going to do a series of videos both on FreeNAS and XP and G using this particular server. So whenever someone asks what server did you do this on, I will just be linking back to this video. So let's go over the details, specs of the server, and a couple other things. But first can you hit the like button because in our algorithm driven world that helps the YouTube algorithm know that other people should watch this video and that you enjoyed it. And it's a good indicator for the system that drives us. Anyways, let's take a look and talk about the specs and dig into the details of this hardware. So I already have the lid off but let's remove the airflow plenum here and get that out of the way to expose the details of this particular server. Now this server actually will support up to 768 gigs of RAM so we don't even have it all filled up. But it is currently has 64 gigs of ACC memory which I know makes some people happy because I'm going to do some FreeNAS videos on it and the big ECC argument. It's moot point on this because well these servers pretty much all come with the ECC. We have the Intel E5 2670 at 2.6 gigahertz. We have two of these. Then we have the Dell Perk H310 Mini. Now if you're not familiar with these, the H310 Mini is part of the RAID expansion because this supports currently in its configuration. It's a 12 drive set up on this system. So this will support all 12 drives but you can also get this server configured in a I believe it's a 24 drive 2.5 inch versus the 12 3.5 inch drives which is what we have right now. But this is an IT mode and we'll cover that in a second but that is IT mode for passing through the drives to the operating system. You can swap these modules out or when you order it you can get a different mode such as this module here. So this is actually a specific RAID controller for hardware RAID. I'm going to do separate videos on some of that but essentially if you want to have the Dell system or this card here control the RAID you would go with something else. If you want the operating system which is what we wanted for this particular series of videos I'm going to do first, you want the H310 in IT mode because that means pass all the drives through the operating system versus a RAID controller takes all the drives groups them together in whichever configuration you want and passes them through as a single hard drive or you can build multiple RAID arrays and each RAID array you build passes through as a single hard drive. So you're basically removing it from the operating systems responsibility for RAID. That's the difference between IT mode and getting an actual RAID card inside of here. The other advantage some of these RAID cards have is they do have things like extra memory chips actually I think it's on this side. Let me move the battery off. Yep some memory chips on different controllers and I'll do a separate video where I cover some of these in more depth like I said but basically this has memory on it has all the RAID settings on it which is what this hanging off here is the battery to hold the RAID settings on there and you're using hardware RAID. You do not want this if you plan to use things like FreeNAS and ZFS you want FreeNAS to have direct control therefore we're going to leave in the H310 in IT mode and like I said we'll cover the settings when we get to the hardware software details of this server. But that's obviously just something important to think about when you're ordering it or if you're ever buying one of these making sure you have the right mode settings on there and then the backplane connector doesn't change it's actually kind of cool because you just swap out this little card pops out you pop the other one in and that will change the functionality of the system. The fans are modular which is really cool and now this goes back to why would I ever want to buy a used server what doesn't have some dust in the fans and things like that well tech supply direct cleans it up really nice for you but this is the other advantage of a server that there's a plenty of in the market. Buy a spare one of these not when it goes bad before it goes bad. Fans do occasionally go bad it's rare but not completely unheard of and depending on I should say depending on the dust levels in your environment generally I don't see that many fans going bad in servers but it's really handy because you can find these cheap even on eBay and keep a spare and set it on top of the server make sure it's a working spare and that way if you ever have a fan alert you don't have to wait a couple days for shipping. Other things inside of here is you notice we have some SATA modules over here and we have a couple spots to put SATA drives right here. I don't have any in here in this particular config. You can get a little pigtail to power the SATA drives but you can put a pair of SSDs back here if you want and I say a pair of them because maybe you want to set things up in raid mode and that's a pretty cool option to be able to have these drives inside as your boot device and then all the drives in front that are under here for the rest of the system for your running all your data. But instead what we've done is it does have an internal USB and yes that's just a sand disk and if you're wondering what the thing is on the back I'll slide it out real quick. We write XCPNG because that's what we loaded on this and you load it and we use this as the main drive so we put in another USB to load this loaded XCPNG and we leave it inside here. Yes I know it's not redundant it's a single one but for demo purposes and for all the lab videos we're going to do that's great. If you wanted something a little better you would get the modules and pop in a couple SSDs back here and obviously that would be your nice way to do this. By the way and I say back here the SSDs actually slide out this way and back in. So if you got this with the SSDs and put them in the back they come out of the back of the server and kind of rack in like that and you would have the connectors right here with the whole system for that. But other than that inside is pretty nice if you didn't know things that are orange generally in Dell that's been their colors came for a while can actually be removed without powering off or restarting the server. Things that are blue you want to have the server off to remove which means we can actually leave this all hooked up and set up and if we have to change a fan out pop the lid off without having any downtime pop that new fan in. But if you ever wanted to break the system apart more there are levers right here that you can pull this entire array out if you wanted it will slide all of this up and out but that's pretty cool. Now the other module part about this is back here we happen to have one two three four network cards in this so four network spots and let's cover and show what those look like at the back of the server over here. So on the back of the server we have two spots for SFP plus and then two RJ45 standard one gig connectors and here's another view of how those back modules will come in and out. So that means I can plug in a 10 gig right here and then my standard RJ45s are going to go here for standard one gig connectivity. So this could go to a storage controller or just a 10 gig switch if we had it that supports SFP or we can use our standard RJ45s. Now all the way over here on the other side is our iDRAC connector and what the iDRAC is is kind of an lights out management system specific to Dell and when we go to these other side of the so we start looking at how the iDRAC works and how you interact with the system you get a better idea how that functions but it's actually really nice. Then we have these dual 750 watt power supplies that are modular and redundant and can be pulled out. Notice the orange tabs while the system is live. So if you have a power supply failure the system can notify you and then you can swap out a power supply. This is also something when we put these infrared clients we go ahead and buy an extra power supply and leave it you know within their IT room. So extra fan, extra power supply that way if one goes bad I don't have to listen to it complain about a bad power supply. You have one on hand just to swap it out. So let's take a look at the front of the system here and we'll just pop a drive out randomly slide it out. Like you said this has a 12, 3.5 inch base on there. SAS connectors are on these. These are what we have some three terabyte drives I think. Yeah we have a handful of three terabyte drives in here that are going to be for storage and doing some of our pass through and me watching through the reflection the camera can still slide these in and out. They're pretty simple. If you want to adapt these and we stuck a couple SSDs in for some of the demos we're going to be doing we just stuck in one of these little plastic adapters. Maybe that's what I'm looking for. So we can pop an SSD in here and slide it right in. Now the system does have in the back here and I didn't I mean didn't cover them in detail but it does have a few PCIe slots so if you want to put some other devices in with the power adapter you do need a pigtail power adapter for it as well that that is right here in the back so you can pop a couple different cards in. Now the next question people ask is how loud is this thing? Not quiet. That's where we're going to be finishing any other room but while it's sitting here I'm going to plug it in so you can hear just how loud this is. So when you first plug it in there is a little bit of a hum. Basically right now the iDRAX system is booting up because like I said there is a lights out so to speak management so you can manage this with only making this much noise because it hasn't really powered up the motherboard and it's booting up the iDRAX system so I can then take control of it which that's we're going to go to next but let's go ahead and turn it on and hear the full noise of this thing. Now it takes a second before it idles down and once the system idles down and it's not doing as much it'll quiet down so they are variable speed on here as far as I know that is the out-of-the-box default setting as we got them. I haven't really adjusted them. There are some adjustments for like how much you want to rev up the fans but generally I want them revving up if the server is under heavy load but it's not unreasonably loud but it is probably a little louder than maybe you want sitting next to you while you're doing a video but it's not a super annoying sound to me but it's still not going to be whisper quiet that's that's just not these systems here. All right so let's go and dive into it and look at the iDRAX system now. All right we have the server booted up and ready to go here so let's go ahead and log in as root and the default password if you didn't know for most iDRAX or at least all the ones I've seen has always been Kelvin you do want to make sure you change it it'll prompt you to do so I've already changed that password from the default c-a-l-v-i-n for those of you wondering and we are now into the iDRAX system now the iDRAX system is a separate integrated Dell remote access controllers to the version seven enterprise version that is the system to monitor the system this is like that lights out management and on the summary page here you can go ahead and we'll do this first we'll launch and see that system's booted up and this is actually showing what the system's displaying so I have full control as if I'm sitting at the console on this and we can reboot shut down the server power it off and all those functions from here we can also inside of here we can go to power on and off and actually forcibly power the server on and off because the Dell iDRAX system is a separate controller if you have problems with the server even with the hardware the iDRAX is able to without the server being so to speak booted up or running able to do things like turn the server on and off and show you what's on the console and even get into the BIOS and change settings on here it's really nice because you don't really need to plug a monitor or anything into this to set these servers up just figure out what the iDRAX IP address is for me I set everything to DHCP and then statically map based on the MAC address so I know it gets the same IP and usually you want to set up a separate management network for all your iDRAX controllers and when you build out a whole rack with these you'll build out a whole lights out so to speak side of the controller of your network so all the controllers are plugged in there and you can physically get into each server even when you're not physically next to that server good when you want to figure out what's going on and if the part goes bad let's go ahead and shut this down so let's actually we're going to reboot it yes and go ahead and restart xcp engine and what I want to do is show you the it mode because we have all the drives pass through to the operating system with the h310 controller and that's what we're going to be showing here is exactly how that gets configured and it's pretty simple so right now the server is worrying up its fans and making all of its noise but it's in the other room so it's not bothering me at all or affecting the video and we'll wait a second here to get to the screen now here's we can go into the system setup uh or the bios boot manager but we actually want to get into the raid config with a control r and it says no configuration present because there's not one we've passed all we've created no disc groups no virtual disc we've done all physical disc and we need to go hit control n here but if i hit control n it spawns a new window in chrome so we'll just do it with a virtual keyboard here and this is where you would set each drive and this is where you can mix a match so we're going to go to f2 for operations convert to raid compatible what i did was converted to non-raid that's why it says that here so each drive can be converted either way so here's the four ssds we have that are as standard sata and it shows you the connector type is sata versus sass these are the toshiba sass drives that are in here and once again we can convert each one of these to raid or non-raid also you may notice with the sass ones i can force led blinking so i can figure out which drive is in which bay but with the sata ones that's not an option on there so that's all i had to do to get this switched over not a big deal with the h310 i don't believe this option is available on some of the other ones like the 7 series controller i believe does not allow pass through which is why you want to use the h310 with it mode and we're using currently the bios in its version 3.0 on this particular controller all right we're going to go ahead and escape out of here and let it boot up press control alt delete to reboot so easy enough go here to console control just hit apply it'll force to reboot and it's going to go through its regular boot up process while we're doing that you can see real quick while that's running through here is the general the way it looks and the way we launch the console is html5 in case you're familiar with the older versions then you cringe because it's like that old java that i really hated where you had to use some weird java thing and yeah it was always a pain before to set these up this is at least more modern in the r720 this is the access controller 7 and it uses html5 for the virtual console but because this is a full management system it does have the option to set up alerts give you a lot of information about the hardware but those alerts can even be from email as in if a hardware major hardware failure happens with your system you can have this because it's on a separate controller unrelated to the operating system it will go through and alert you that something has happened to the server that's part of the lights out management and that's why it runs independent of the actual operating system the idrac system is an operating system into itself but it gives you all the details all the hardware uh statuses of everything power status cpu memory so you can look up not just what's in the machine but the health of those things if there's any type of problems with it or there's some type of issues going on but all those little details are completely available through the idrac which is really nice you can also take a look at the physical disk in the idrac so it'll give you all the detailed information about each physical disk if you have built this using the virtual disk as in you've built this with the park controller in raid mode then it will give you the status of the raid controller because then the operating system is blind to what's going on with the re controller and you can see it directly from inside of here so you can control replacing drives and everything else manage create build unbuild the only thing i don't think was possible in here double check i think you have to go into that bios option to set these in non raid mode their status is non raid mode here okay it does have convert to raid but i don't think it let me unconvert them uh that's why i had to go into bios do that i can't remember and because i've already got these disks set up already in the system i didn't want to i don't want to retry that but it does show the if you have more than one controller even you'll be able to go on here and do that also if you're using it in raid mode and letting this handle the raid the park controller handle the raid you can configure hot spares for example and what that'll allow you to do is have a spare on the ready to drop in if there's a raid failure kind of making the ease of management there for you so if you want to let that if you want to let the whole system handle it all for you that absolutely is possible and in some circumstances you may want the system to do it because you don't want to deal with configuring the raid an xcp ng or whatever other operating system you may be putting on there you can have it just create one big raid array load the operating system to it operating system sees one hard drive treats it as a single hard drive but it's actually a group of hard drives being managed by the perk controller which you know that can be advantageous power monitoring this is a cool feature because you can check the health you can see exactly how many watts it's using what percentage of capacity that is it will even track it over time so because we rebooted it we shut it down for a second so here is our low power which is no watts here's our spinning up all the fans at about 270 watts and then we're idling currently with the dual power supplies at 196 watts this thing will also track over time how many kilowatt hours that it may be using that is a really good thing if you're going just how much does this cost well you look up here what you pay per watt what you pay per kilowatt hour from your lecture company and from there you can then calculate out exactly how much this will cost to operate so that's obviously a question that a lot of people have is if i build this home lab just how much power does this need so sitting here idling like i said about 196 watts but that's going to go up and ramp up as you add load to the system or as you add more things for it to do and it scales so the wattage will go up and it will peek out it has a warning once it hits about 900 watts with a failure threshold being at 980 watts like i said they do sell that bigger power supply if you wanted to go more than 750 but that's pretty much it for a good overview of the server like i said it's a great server i'll be doing a lot of videos on it for both xtpg and free nas and when people ask what server i'm going to use i'm going to talk about this one from tech supply direct they were great enough to supply this and they do have that offer code so you can get your 10 off and if you're interested in purchasing this del 12g power edge r720 xd with the 12 bay like we have configured here i basically ran through the same configuration so it's about two grand for this system that would be with the two x intel xeon 2670 64 gig ram the h3 10 uh no extra back plane and 12 three terabyte sass drives that's actually nice they have all the costs broken down here and if you chose to do just say the drives which is an option they actually shipped to me with 12 sass drives in it i put in a couple ssds we're swapping back and forth for doing some testing but you can see that it's actually almost a thousand of the price so if you were to buy the hard drive separate yes you can get this with no hard drives in it choose that as an option and knock a thousand dollars off and just get the chassis and start sticking your own drives or maybe you have your own drives to put in uh but that's it go ahead and use our offer code to get 10% off your order and uh fill it all out oh i drive enterprise versus the i drive express those are both options the i drive enterprise just cost a little bit more but they have that on the spec sheet here on del's website you can read about the differences between the express connector versus the enterprise connector i will leave that because that question does come up about hey my i direct doesn't look like yours so i want to i'll make sure to leave that link here in the description all right thanks thanks for watching if you like this video give it a thumbs up if you want to subscribe to this channel to see more content hit that subscribe button and the bell icon and maybe youtube will send you a notice when we post if you want to hire us for a project that you seen or discussed in this video head over to laurancesystems.com where we offer both business it services and consulting services and are excited to help you with whatever project you want to throw at us also if you want to carry on the discussion further head over to forums.laurancesystems.com where we can keep the conversation going and if you want to help the channel out in other ways we offer affiliate links below which offer discounts for you and a small cut for us that does help fund this channel and once again thanks again for watching this video and see you next time


Welcome to all of you, myself Ravindra Chauhan, Assistant Professor, Department of Electronics Engineering, Walsh and Insta of Technology, Solar Board. So today in this session we will discuss the serial communication in 8051. The learning outcome of this session is, after this session student will be able to design the system which supports the serial data transfer and receive using the microcontroller 8051. Outline of our discussions is like this, first we will go through the basics of the serial communication. First we will see how the 8051 supports the serial communication and third one is we will write the algorithm for serial data transfer and receive. The first you should know what do you mean by data communication. Now in the processor based system data communication means the exchange of data or exchange of information between the devices. Now this information can be exchanged in number of ways that is called the types of different communication. The way in which the data is transmitted or received depending upon that the classification is done like simplex communication, half duplex communication, full duplex communication. In simplex communication the transmitter and the receivers are fixed. The transmitter is transmitting the information all the times and the receiver is receiving the information all the times. The best example of this type of communication is the radio broadcasting. The next communication type is called the half duplex communication. In half duplex communication the device can be worked either as a transmitter or the receiver. Means data can be sent in both the directions but only in one direction at the same time. So the example of half duplex communication you will find in the device walkie-talkie. Where the device normally we are using the telephone which supports the full duplex communication. In full duplex communication data can be transmitted and the received in both the direction at the same time. Another classification of the data transfer is done how the data is transferred. So first type is called the parallel data transfer, second is called the serial data transfer. In parallel data transfer the number of lines wires are drawn between the transmitter and the receiver. Normally in the controller based system the eight or more wires are used to transfer or receive the data. It is the parallel data transfer is used for data transfer over short distance that is few feet away because the more number of lines or wires are required. But here as the number of bits can be transferred or received at the same time the parallel data transfer is the faster one. And in serial data transfer only one wire is sufficient to transmit the data between transmitter and receiver. Now in serial data transfer only one bit is transferred at the same time. Now serial data transfer mainly it is preferable while transferring the data over long distance. Now in this data transfer only one bit is transmitted at the same time that is why serial data transfer is slower compared to the parallel data transfer. Now the serial data transfer are classified mainly in two categories one is called the synchronous data transfer and second is called asynchronous data transfer. When synchronous data transfer before sending the actual data or the information the predefined sync characters are exchanged between transmitter and the receiver. And when transmitter and receiver are get synchronized to each other then the block of data is transferred at a time. Since one by one all the characters or bytes are transferred. In asynchronous data transfer the data transfer takes the character whites if it will send the one character after that the second character and so on. Now to transfer the one character in asynchronous data transfer the frame is designed which contains the start bit then the 8 bit of the characters to be transferred or normally to transfer the data serially or the characters serially its ASCII value is to be used. So 8 bit ASCII value of the character to be transferred and lastly the stop bit. So for each character one frame is designed and then these frames are sent one by one. Now in the serial data transfer in 805 for that the two pins are provided called the Rxd and Txd which are multiplexed with the port pin P3.0 and P3.1 respectively. P3.0 that is the receive pin is used to receive the one bit of information at a time and one bit of a information can be transmitted through the pin P3.1 that is called the Txd pin and this 805 one supports only the asynchronous data transfer. For one character to be transferred a frame is designed which is shown below. The first bit is called the start bit then the 8 bit ASCII value of character which is actually to be transmitted and lastly the stop bits. In 805 one the start bit is kept at logic 0 and stop bit is kept at logic 1. Now for the serial data transfer in 805 one the two special function registers are provided the one is called S buff and second one is called S call. The S buff register is used to store the actual character to be transferred via the Txd line. So whenever you are going to transfer the character serially it requires to put that character first in the S buff register. Whenever we are putting the any character in S buff register the transmission will start and whatever the character received through Rxd pin that character is also get stored into the S buff register. Now internally this S buff are the two different entities, two different registers but we are accessing these registers with the same address same name that is the S buff but these two registers are differentiated by their operation. The one used for transmission that S buff is always written by the controller and the S buff which receives the received character that S buff register is also is always read by the 805 one. Next special function register is provided which is named as S con register. S con register is used to configure the modes of operation of serial communication and the bit format defined for the S con registers are shown below. The three MSB bits SM0, SM1 and SM2 these three bits are used to decide the actual mode of operation like this. So when SM0 is 0, SM1 is 0 we are saying that the 805 one is operating in mode 0. Similarly when SM0 is 0 SM1 is 1 we are selecting the mode 1 operation of the 805 one and so on. Now the mode 0 is work as simply 8 bit shift register mode. So normally the peoples are not going for the use of the mode 0 then the widely used mode of operation is the 8 bit UART for that SM0 must be 0 and SM1 must be 1 and SM2 bit enables the multiprocessing capability of the 805 one in mode 2 and mode 3. As far as the data transfer rate that is the board rate is concerned the board rate is variable in mode 1 and mode 3 where in mode 0 and the mode 2 the board rate is fixed. Now the last two bits which is called the flag bits TI transmit interrupt flag and RI stands for receive interrupt flag. Now this TI flag is set when 805 one completes the transmission of a character to indicate that now the 805 one is ready to transfer the next byte or the next character. RI flag is set when 805 one receive the character and placed in the SBUFF register and it indicates that this byte has been received and should be read before it is lost. Now to enable the receiver of the 805 one REN bit is to be set. If REN bit is 0 the receiver is disabled and TB8 and RB8 are used when you are designing the frame with the 11 bits where the 11 bit is used as a parity bit which is used for parity or the error detection. Then the algorithm for to transfer the data serially as far as the 805 one is concerned first initialize the timer one in mode 2 timer mode to decide the data transfer rate that is the board rate. Now you pause the video and recall how to initialize the timer one. Now to initialize the timer one load the T-MOD register with the value 20H to operate timer one in mode 2 timer mode. Internally only the timer one is associating with the serial communication that's why to decide the board rate all the times timer one is to be used. After initializing the timer one in mode 2 timer mode. Next step is load the TH1 register with one of the values to set the board rate for serial data transfer. Now how will you find the TH1 value for that use the formula that is board rate is equal to 2 raised to S mod divided by 32 whole multiplied by oscillator frequency divided by 12 into 256 minus TH1. Now the board rate we are deciding so board rate it is always known quantity. So only unknown quantity is TH1 so from this you find the TH1 value to get the required board rate and put in the TH1 register. This S mod bit is from the pecan register by default S mod bit is reset. So this bit is provided to double the board rate by keeping the same value in TH1 register by setting the S mod bit. Then load the Scon register with the value 50H to select the mode one with receiver enable where an 8 bit data is framed with start bit and stop bit. So first start bit will be sent then the 8 bit of the actual character and lastly the stop bit will be gates transmitted. Next start the timer so that the clock will be generated then clear the timer interrupt flag to indicate that the previous character has been transmitted then write the character by to be transferred serially into the S buff register. When you are putting the character in the S buff register the transmission will start. Now next you have to wait till the transmission is not completed. For that you continuously monitor the status of TI flag bit to see if the character has been transferred completely or not. If you find TI bit is set that means the character is transferred now you can put the next character into the S buff register. So before that you clear the TI flag and put the next character to be transferred in the S buff register. So references used for this particular topic microcontrollers by Ajay Deshmukh and 8051 and embedded C program by Mazidi and Mazidi. Thank you.


Gunnery is going to be going on for about two weeks. Our main purpose is to try to get people, as in crew chiefs, through to get called on shooting from the aircraft while actually flying. Gunnery was something important for us to knock out because it is a requirement. So for us to be ready as a unit to mobilize at any moment, we need to make sure we are called and that we are proficient. Yeah, so whenever we do fly, we do have a flight instructor that sits in the back with us to maintain the safety in the back because we do have live rounds. We're in a live range. They watch everything that you do. They watch you load, unload. They watch you shoot. They watch your rounds walk into the target to see if you can actually shoot from a moving platform. Here in Kuwait, we're on the CRTF mission. If we need to mobilize at any moment, throughout the AO, we can load up and everybody's aware of what we're doing and knows what everybody's job is.