Linux kernel release 3.x <http://kernel.org/> These are the release notes for Linux version 3. Read them carefully, as they tell you what this is all about, explain how to install the kernel, and what to do if something goes wrong. WHAT IS LINUX? Linux is a clone of the operating system Unix, written from scratch by Linus Torvalds with assistance from a loosely-knit team of hackers across the Net. It aims towards POSIX and Single UNIX Specification compliance. It has all the features you would expect in a modern fully-fledged Unix, including true multitasking, virtual memory, shared libraries, demand loading, shared copy-on-write executables, proper memory management, and multistack networking including IPv4 and IPv6. It is distributed under the GNU General Public License - see the accompanying COPYING file for more details. ON WHAT HARDWARE DOES IT RUN? Although originally developed first for 32-bit x86-based PCs (386 or higher), today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell, IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS, Xtensa, Tilera TILE, AVR32 and Renesas M32R architectures. Linux is easily portable to most general-purpose 32- or 64-bit architectures as long as they have a paged memory management unit (PMMU) and a port of the GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has also been ported to a number of architectures without a PMMU, although functionality is then obviously somewhat limited. Linux has also been ported to itself. You can now run the kernel as a userspace application - this is called UserMode Linux (UML). DOCUMENTATION: - There is a lot of documentation available both in electronic form on the Internet and in books, both Linux-specific and pertaining to general UNIX questions. I'd recommend looking into the documentation subdirectories on any Linux FTP site for the LDP (Linux Documentation Project) books. This README is not meant to be documentation on the system: there are much better sources available. - There are various README files in the Documentation/ subdirectory: these typically contain kernel-specific installation notes for some drivers for example. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Changes file, as it contains information about the problems, which may result by upgrading your kernel. - The Documentation/DocBook/ subdirectory contains several guides for kernel developers and users. These guides can be rendered in a number of formats: PostScript (.ps), PDF, HTML, & man-pages, among others. After installation, "make psdocs", "make pdfdocs", "make htmldocs", or "make mandocs" will render the documentation in the requested format. INSTALLING the kernel source: - If you install the full sources, put the kernel tarball in a directory where you have permissions (eg. your home directory) and unpack it: gzip -cd linux-3.X.tar.gz | tar xvf - or bzip2 -dc linux-3.X.tar.bz2 | tar xvf - Replace "X" with the version number of the latest kernel. Do NOT use the /usr/src/linux area! This area has a (usually incomplete) set of kernel headers that are used by the library header files. They should match the library, and not get messed up by whatever the kernel-du-jour happens to be. - You can also upgrade between 3.x releases by patching. Patches are distributed in the traditional gzip and the newer bzip2 format. To install by patching, get all the newer patch files, enter the top level directory of the kernel source (linux-3.X) and execute: gzip -cd ../patch-3.x.gz | patch -p1 or bzip2 -dc ../patch-3.x.bz2 | patch -p1 Replace "x" for all versions bigger than the version "X" of your current source tree, _in_order_, and you should be ok. You may want to remove the backup files (some-file-name~ or some-file-name.orig), and make sure that there are no failed patches (some-file-name# or some-file-name.rej). If there are, either you or I have made a mistake. Unlike patches for the 3.x kernels, patches for the 3.x.y kernels (also known as the -stable kernels) are not incremental but instead apply directly to the base 3.x kernel. For example, if your base kernel is 3.0 and you want to apply the 3.0.3 patch, you must not first apply the 3.0.1 and 3.0.2 patches. Similarly, if you are running kernel version 3.0.2 and want to jump to 3.0.3, you must first reverse the 3.0.2 patch (that is, patch -R) _before_ applying the 3.0.3 patch. You can read more on this in Documentation/applying-patches.txt Alternatively, the script patch-kernel can be used to automate this process. It determines the current kernel version and applies any patches found. linux/scripts/patch-kernel linux The first argument in the command above is the location of the kernel source. Patches are applied from the current directory, but an alternative directory can be specified as the second argument. - Make sure you have no stale .o files and dependencies lying around: cd linux make mrproper You should now have the sources correctly installed. SOFTWARE REQUIREMENTS Compiling and running the 3.x kernels requires up-to-date versions of various software packages. Consult Documentation/Changes for the minimum version numbers required and how to get updates for these packages. Beware that using excessively old versions of these packages can cause indirect errors that are very difficult to track down, so don't assume that you can just update packages when obvious problems arise during build or operation. BUILD directory for the kernel: When compiling the kernel, all output files will per default be stored together with the kernel source code. Using the option "make O=output/dir" allow you to specify an alternate place for the output files (including .config). Example: kernel source code: /usr/src/linux-3.X build directory: /home/name/build/kernel To configure and build the kernel, use: cd /usr/src/linux-3.X make O=/home/name/build/kernel menuconfig make O=/home/name/build/kernel sudo make O=/home/name/build/kernel modules_install install Please note: If the 'O=output/dir' option is used, then it must be used for all invocations of make. CONFIGURING the kernel: Do not skip this step even if you are only upgrading one minor version. New configuration options are added in each release, and odd problems will turn up if the configuration files are not set up as expected. If you want to carry your existing configuration to a new version with minimal work, use "make oldconfig", which will only ask you for the answers to new questions. - Alternative configuration commands are: "make config" Plain text interface. "make menuconfig" Text based color menus, radiolists & dialogs. "make nconfig" Enhanced text based color menus. "make xconfig" X windows (Qt) based configuration tool. "make gconfig" X windows (Gtk) based configuration tool. "make oldconfig" Default all questions based on the contents of your existing ./.config file and asking about new config symbols. "make silentoldconfig" Like above, but avoids cluttering the screen with questions already answered. Additionally updates the dependencies. "make olddefconfig" Like above, but sets new symbols to their default values without prompting. "make defconfig" Create a ./.config file by using the default symbol values from either arch/$ARCH/defconfig or arch/$ARCH/configs/${PLATFORM}_defconfig, depending on the architecture. "make ${PLATFORM}_defconfig" Create a ./.config file by using the default symbol values from arch/$ARCH/configs/${PLATFORM}_defconfig. Use "make help" to get a list of all available platforms of your architecture. "make allyesconfig" Create a ./.config file by setting symbol values to 'y' as much as possible. "make allmodconfig" Create a ./.config file by setting symbol values to 'm' as much as possible. "make allnoconfig" Create a ./.config file by setting symbol values to 'n' as much as possible. "make randconfig" Create a ./.config file by setting symbol values to random values. "make localmodconfig" Create a config based on current config and loaded modules (lsmod). Disables any module option that is not needed for the loaded modules. To create a localmodconfig for another machine, store the lsmod of that machine into a file and pass it in as a LSMOD parameter. target$ lsmod > /tmp/mylsmod target$ scp /tmp/mylsmod host:/tmp host$ make LSMOD=/tmp/mylsmod localmodconfig The above also works when cross compiling. "make localyesconfig" Similar to localmodconfig, except it will convert all module options to built in (=y) options. You can find more information on using the Linux kernel config tools in Documentation/kbuild/kconfig.txt. - NOTES on "make config": - Having unnecessary drivers will make the kernel bigger, and can under some circumstances lead to problems: probing for a nonexistent controller card may confuse your other controllers - Compiling the kernel with "Processor type" set higher than 386 will result in a kernel that does NOT work on a 386. The kernel will detect this on bootup, and give up. - A kernel with math-emulation compiled in will still use the coprocessor if one is present: the math emulation will just never get used in that case. The kernel will be slightly larger, but will work on different machines regardless of whether they have a math coprocessor or not. - The "kernel hacking" configuration details usually result in a bigger or slower kernel (or both), and can even make the kernel less stable by configuring some routines to actively try to break bad code to find kernel problems (kmalloc()). Thus you should probably answer 'n' to the questions for "development", "experimental", or "debugging" features. COMPILING the kernel: - Make sure you have at least gcc 3.2 available. For more information, refer to Documentation/Changes. Please note that you can still run a.out user programs with this kernel. - Do a "make" to create a compressed kernel image. It is also possible to do "make install" if you have lilo installed to suit the kernel makefiles, but you may want to check your particular lilo setup first. To do the actual install, you have to be root, but none of the normal build should require that. Don't take the name of root in vain. - If you configured any of the parts of the kernel as `modules', you will also have to do "make modules_install". - Verbose kernel compile/build output: Normally, the kernel build system runs in a fairly quiet mode (but not totally silent). However, sometimes you or other kernel developers need to see compile, link, or other commands exactly as they are executed. For this, use "verbose" build mode. This is done by inserting "V=1" in the "make" command. E.g.: make V=1 all To have the build system also tell the reason for the rebuild of each target, use "V=2". The default is "V=0". - Keep a backup kernel handy in case something goes wrong. This is especially true for the development releases, since each new release contains new code which has not been debugged. Make sure you keep a backup of the modules corresponding to that kernel, as well. If you are installing a new kernel with the same version number as your working kernel, make a backup of your modules directory before you do a "make modules_install". Alternatively, before compiling, use the kernel config option "LOCALVERSION" to append a unique suffix to the regular kernel version. LOCALVERSION can be set in the "General Setup" menu. - In order to boot your new kernel, you'll need to copy the kernel image (e.g. .../linux/arch/i386/boot/bzImage after compilation) to the place where your regular bootable kernel is found. - Booting a kernel directly from a floppy without the assistance of a bootloader such as LILO, is no longer supported. If you boot Linux from the hard drive, chances are you use LILO, which uses the kernel image as specified in the file /etc/lilo.conf. The kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or /boot/bzImage. To use the new kernel, save a copy of the old image and copy the new image over the old one. Then, you MUST RERUN LILO to update the loading map!! If you don't, you won't be able to boot the new kernel image. Reinstalling LILO is usually a matter of running /sbin/lilo. You may wish to edit /etc/lilo.conf to specify an entry for your old kernel image (say, /vmlinux.old) in case the new one does not work. See the LILO docs for more information. After reinstalling LILO, you should be all set. Shutdown the system, reboot, and enjoy! If you ever need to change the default root device, video mode, ramdisk size, etc. in the kernel image, use the 'rdev' program (or alternatively the LILO boot options when appropriate). No need to recompile the kernel to change these parameters. - Reboot with the new kernel and enjoy. IF SOMETHING GOES WRONG: - If you have problems that seem to be due to kernel bugs, please check the file MAINTAINERS to see if there is a particular person associated with the part of the kernel that you are having trouble with. If there isn't anyone listed there, then the second best thing is to mail them to me (torvalds@linux-foundation.org), and possibly to any other relevant mailing-list or to the newsgroup. - In all bug-reports, *please* tell what kernel you are talking about, how to duplicate the problem, and what your setup is (use your common sense). If the problem is new, tell me so, and if the problem is old, please try to tell me when you first noticed it. - If the bug results in a message like unable to handle kernel paging request at address C0000010 Oops: 0002 EIP: 0010:XXXXXXXX eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx ds: xxxx es: xxxx fs: xxxx gs: xxxx Pid: xx, process nr: xx xx xx xx xx xx xx xx xx xx xx or similar kernel debugging information on your screen or in your system log, please duplicate it *exactly*. The dump may look incomprehensible to you, but it does contain information that may help debugging the problem. The text above the dump is also important: it tells something about why the kernel dumped code (in the above example, it's due to a bad kernel pointer). More information on making sense of the dump is in Documentation/oops-tracing.txt - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump as is, otherwise you will have to use the "ksymoops" program to make sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred). This utility can be downloaded from ftp://ftp.<country>.kernel.org/pub/linux/utils/kernel/ksymoops/ . Alternatively, you can do the dump lookup by hand: - In debugging dumps like the above, it helps enormously if you can look up what the EIP value means. The hex value as such doesn't help me or anybody else very much: it will depend on your particular kernel setup. What you should do is take the hex value from the EIP line (ignore the "0010:"), and look it up in the kernel namelist to see which kernel function contains the offending address. To find out the kernel function name, you'll need to find the system binary associated with the kernel that exhibited the symptom. This is the file 'linux/vmlinux'. To extract the namelist and match it against the EIP from the kernel crash, do: nm vmlinux | sort | less This will give you a list of kernel addresses sorted in ascending order, from which it is simple to find the function that contains the offending address. Note that the address given by the kernel debugging messages will not necessarily match exactly with the function addresses (in fact, that is very unlikely), so you can't just 'grep' the list: the list will, however, give you the starting point of each kernel function, so by looking for the function that has a starting address lower than the one you are searching for but is followed by a function with a higher address you will find the one you want. In fact, it may be a good idea to include a bit of "context" in your problem report, giving a few lines around the interesting one. If you for some reason cannot do the above (you have a pre-compiled kernel image or similar), telling me as much about your setup as possible will help. Please read the REPORTING-BUGS document for details. - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you cannot change values or set break points.) To do this, first compile the kernel with -g; edit arch/i386/Makefile appropriately, then do a "make clean". You'll also need to enable CONFIG_PROC_FS (via "make config"). After you've rebooted with the new kernel, do "gdb vmlinux /proc/kcore". You can now use all the usual gdb commands. The command to look up the point where your system crashed is "l *0xXXXXXXXX". (Replace the XXXes with the EIP value.) gdb'ing a non-running kernel currently fails because gdb (wrongly) disregards the starting offset for which the kernel is compiled.
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Angular-Directive-Project Directives range from very basic to extremely complex. This project will build up to some somewhat difficult directives. Keep in mind that the format we're learning for directives is the same format used to build some extremely complex things in angular. Using directives often and well is one way to show you're a talented developer. Starting Out We've included only a few things for you to begin with. index.html, app.js, styles.css. At this point the best way to get more comfortable with angular is to initialize an app without relying heavily on boilerplate code (reusable code that starts out your projects for you). You'll notice that in the index.html we've included the angular-route CDN. Yes, we'll be using angular's router here. Put an ng-view into your index.html. In your app.js set up a config and set up our first route for when a user is at the '/home' url. If you're having trouble remembering how to set up the router go look at how you set up the router on the previous project. One way these projects will be beneficial to you is allowing you to look back at something *you** did and seeing how you got that something to work.* You may also want add an otherwise that defaults to /home. Create a controller and a template file for this route in your app folder. Don't forget to include the controller as a script in your index.html Check that everything is hooked up correctly. Try adding a div with some text in your home template just to make sure it's showing up. Once you've got that going you're ready to start on some directives. Now let's make our directive. We'll start with a simple one that we can use to display information passed to it. Step 1. Start your directive Woot. When you're initializing your directive just remember that it works very similarly to how you start up a controller or a service. It can also be very helpful to think of your directive as a route. Create your directive. You'll use the directive method on your angular module. It takes two arguments, the name string and the callback function, which will return the object that represents your directive. When naming your directive give it a name with two words; dirDisplay would be nice, but anything works. Just remember it's best practice to give a directive a camel case name so that it's clear in your html what it is. Also we're going to need a template html for our directive. We could do it inline, but let's make another file instead. Just name it something that makes sense for the name of your directive and put it in the same directory as your directive file. For your template just make a <div> and inside a <h1> tag that says User. Now in your home route html add in your directive. It will look like this if you named it dirDisplay: <dir-display></dir-display> Start up your app and go to the home route. Check and make sure you see User where your directive was placed. If you're not seeing it at this point it could mean a few things. Here's some more common issues. You didn't link your directive in your index as a script. Your name for your directive doesn't match the name in your html. Remember camel case becomes snake case so myDirective becomes <my-directive></my-directive>. You're file path to your html template is wrong. You have to think of file paths in angular as relative to the index. Here's some code to see just for this part, and just for the directive's js file. var app = angular.module('directivePractice'); app.directive('dirDisplay', function(){ return { templateUrl: 'app/directives/dirDisplay.html' }; }); What we're returning is the directive object. You won't see anymore code in this tutorial so it's important you get things working right and refer back to what you've already done to advance from now on. Step 2. Advancing directives Your directive should be loaded up now, but it's not really doing much. Let's make it better. In your home controller. Make a variable on your $scope called user. Set it's value to { name: "Geoff McMammy", age: 43, email: "geofdude@gmail.com" } Now inside your directive's html specifically inside the <h3> tags display our new user's name. Then inside maybe some <h4> tags display his email and age. This is going to work exactly the same as if it was just inside your home controller. Reload the page and make sure it works. This is still very cosmetic and really not all that useful. It needs functionality. Add into your directive's object the link property. The link property's value is a function definition that takes (generally) three parameters. scope, element, and attributes. Unlike in other places with angular injection these parameter names don't carry meaning. The first parameter will always represent your $scope for that directive, the second will always be the element that wraps your whole directive, and the third will always be an object containing all the properties and values of the attributes on your directive in the dom. Try the following to get a feel for all three. Add two attributes to your directive in your html. Like this - <dir-display test="myTest" my-check="checkItOut"></dir-display> Now in the link property you've added console.log the three parameters in the function. You'll see an object for scope that should look identical to the $scope of your html function. For element you'll see an object the represents the DOM wrapper for your directive. For attributes you'll see an object that will look like this: { test: "myTest", myCheck: "checkItOut" } An important thing to notice is how it has again converted snake case to camel case for you. my-check became myCheck. Don't forget this. You'll run into this issue one day. It counts for both attributes and directive names. To feel some of what the link function could do let's try this. Add a ng-show to both the email and age wrappers. This should be familiar to you. Now inside your link function add a click event listener to your element property. It's going to look just like jQuery. element.on('click', function(){ }) Inside the click listener's callback add a toggle for the ng-show property you passed in. Along with a console.log to make sure things are connecting when you click. Try it out. Don't call for a mentor when it doesn't work. Let's talk about that first. You should see the console.log firing, but why isn't it toggling. This is going to be a common problem when working with the link function and event listeners. What we have here is an angular digest problem. The value is changing on the scope object, but the change isn't being reflected by our DOM. That's because angular isn't aware of the change yet. Anytime we cause an event to happen using something like jQuery or even angular's jQLite we need to let angular know that we've made a change. Add this line of code in place of your console.log, scope.$apply(). Now try it out. It should be working now, so if you're still having issues it's time to debug. What we've done is forced angular to run it's digest cycle. This is where angular checks the scope object for changes and then applies those to the DOM. This is another good lesson to learn for later. You'll most likely hit this when making changes to your element using event listeners. Step 3. Directive's re-usability. Now our directive has some extremely basic functionality. One of a directive's greatest advantages though is its ability to be placed anywhere and still be functional. Let's say instead we had a list of users instead of just one. Change the $scope property in your home controller to be users and give it this array as its value: [ { name: "Geoff McMammy", age: 43, email: "geofdude@gmail.com", city: "Provo" }, { name: "Frederick Deeder", age: 26, email: "fredeed@gmail.com", city: "Austin" }, { name: "Spencer Rentz", age: 35, email: "spencerrentz@gmail.com", city: "Sacramento" }, { name: "Geddup Ngo", age: 43, email: "geddupngo@gmail.com", city: "Orlando" }, { name: "Donst Opbie Leevin", age: 67, email: "gernee@gmail.com", city: "Phoenix" } ] Now in your home HTML add a ng-repeat to the directive call. Tell it to repeat for each user in users. Reload your page. It's working! But why? How does each directive instance know what information to display? In the link function console.log the scope parameter. Make sure it's outside of your click listener. You'll see five print outs in your console. Open up any one of them and look to the bottom. Open up the user property. It's exactly what we would want! But again why would that be the case? Don't get too caught up in this next bit if it's too hard to understand, but the ng-repeat is essentially making new tiny scope objects for each individual user in our users array. Now each of our directives is still getting a user property on the scope object just like the directive wanted in the beginning. Woot. Step 4. Ramp it up with Isolate Scope. Directives can do so much more. So let's make that happen. That means we should make.... a new directive!!! This directive's purpose will be to display a selected User and the weather in his/her/its location. Link it up just like the last one. Create a js file for our directive and name it dirWeather. Make an html file named dirWeather.html. Link it up in your index.html and add the template to your new directive object. In your directive's template give it an <h3> tag that says Weather just so we can know it's working. Above your ng-repeat on dirDisplay add your new dirWeather directive. If it's not working check the instructions above as to some common reasons why before asking a mentor for help. If you're seeing the Weather text on your page then we're ready to try out the dreaded Isolate Scope. The isolate scope object is one of the stranger API's in angular. I'm sorry but it is. Just refer to this for now. scope: { string: '@', link: '=', func: '&' } The properties on the scope object represent the attributes on the directive in the html. Our example scope object here would look something like this in the html. <example-directive string="a string" link="user" func="updateUser()"></example-directive> The hard part here is the @, =, and &. They each have very important and distinct meanings. @ says take in my attribute value as a string. = says take in my attribute value as a two-way bound variable from the parent scope. & says take in my attribute value as a reference to a function on the parent scope. It's also critical to point out that once you add a scope object you have no isolated your directive's scope. Meaning, aside from the values passed in through attributes, this directive has no connection to the $scope of its parent. That being said let's isolate our directive's scope. :worried: Add the scope property to your dirWeather. Give it the value of an object with a property of currentUser whose value is '='. Remember in your html this will look like current-user. This is the third time I've said so don't expect it again. This means that whatever comes into the currentUser attribute is going to be a value of the parent's scope object. For now test this out by passing in users[0]. Find a way to show that users information inside your dirWeather's html. Remember inside your directive now the user is represented by currentUser. Step 5. &? &!? The '=' value on your scope object has created a two-way binding between users[0] and currentUser. Now let's try out the '&'. On your home controller add a function called getWeather. It takes one parameter called city. This function will make a call to a service so we'll need to create that. Make a weather service. Name it something cool and creative like weatherService. Inside the weather service make a function called getWeather that also takes one parameter, city. Make an $http get to this url - 'http://api.openweathermap.org/data/2.5/weather?q=' After the q= add on the city parameter. If you want you can test this out in postman. See what kind of data you get back. If it's the weather of that city then... you win! Use $q to return a promise that only resolves with the data you want. Temperature (preferably not in Kelvin) and the weather description. Use console.log on the data coming from the $http request to get to what you want. You'll need to add both on an object that you resolve your new promise with. On your home controller have it return the result of invoking the get getWeather function on the service. You should be returning a promise. Now in your home route's HTML pass in the getWeather function to the dirWeather directive through an attribute called weather-call. Add the attribute to your isolate scope object. That was a lot of linking, but let's walk through it. Your controller has a function linked to the service, which is in turn linked to your directive. So if you run the weatherCall function in your directive it will go through your controller to your service and then back. Now things get a little bit tricky. Angular's way of passing along arguments through a directive to your controller are tricky, but once you understand how to do it, it's not hard. I'm going to give an example here of how it works. <my-directive pass-func="callFunc(data)"></my-directive> Here's how it would look in your HTML. But where's the data supposed to be coming from? It seems that you'd rather be able to pass in data from your directive. Well you still can, you just have to essentially tell angular what do use as an argument to replace data when it calls that function in your controller. The actualy function call inside the directive will look like this. $scope.passFunc({data: wantedData}) So what you'll do is pass in an object where the property name is what the argument is named in the HTML where you call the directive. That might sound confusing, but just look at the two code blocks above for a pattern. Note that pass-func becomes $scope.passFunc and data is being replaced with wantedData with the {data: wantedData} object. In our directive we want to replace city in the attribute call, for something else inside the directive. You'll follow the same pattern as above. For now let's get things set up for that function call. Add to the dirWeather directive object a property called controller. It's value will be a function. Yes, this is a controller specifically for your one directive. It works the same as any other controller, except you don't give it a name. It's $scope object will only be accessible within an instance of your directive. Don't forget to inject $scope in the function. Inside your controller function run the weatherCall function with the city property from the currentUser on your $scope. Here's where you need to make sure you've passed in a city argument in the attribute function call, and then replace that with your currentUser's city using an object with a city property. The function call should return a promise, so call .then afterward and add the data onto your $scope to display both the weather and temperature of the currentUser's city. The properties can be named whatever makes sense to you. You may also want to find a way to get rid of all the decimal places on your temperature. Now you should have everything hooked up so it shows Geoff's data and the weather data for Provo. But is that good enough? Step 6. Ramping up our ramp up. Now let's change this so it shows the weather data for whichever user we select. We're going to need to use '&' again. Make a function on the home controller that takes in a parameter and sets a property on the $scope to be that parameter. Maybe you see where this is going. We want to get this function into our dirDisplay controller. But in order to do that we need to isolate dirDisplay's scope. This also means we need to pass in each individual user through the scope object as well. To make it easier on ourselves, let's pass the current user from our ng-repeat into our directive through a user attribute. This way we can leave our two-way bindings as they are. Also pass our new function that sets our current user from our home controller into our directive through a setUser attribute. You'll need to add an argument in there again. Go with user. Your scope object in dirDisplay should have two properties. setUser with the value of '&' and user with the value of '='. As before we're going to need to do some tricky stuff to get our argument back to our controller. Call the setUser function inside our click event listener and pass in an object the sets our user argument to be the user on our directive's scope object. If you've forgotten this part go back up and take a look at how you did it before or the example in this README. Whatever user you click on now should show up in the dirWeather directive as the current user. But we're missing one thing, we want to be able to see the weather for that user too. We'll have to do one more thing that will seem a little bit tricky at first, but it's good to learn if you don't know it already since it's actually used quite frequently. We need to step up a change listener on our currentUser in the dirWeather directive. We'll use angular's $watch functionality. $watch is a method on your $scope that will watch for changes in a variable you give it. It works in two ways. $scope.$watch('property', function(value){ console.log("When $scope.property changes its new value is: ", value) }); And $scope.$watch(function(){ return myVar }, function(value){ console.log("When myVar changes its new value is: ", value); }); Remove the immediate function call that we have in there now. Maybe just comment it out for now because we'll use it in a bit. Now call the $watch method on your scope and have it watch currentUser. Either way of using $watch is fine. Have its callback run the $scope.weatherCall function just like you had it before. One thing to note is that $scope.$watch will always run once to begin with. Since that's what we want here it's great, but just be aware of that. If you've reached this point congratulate yourself. You've messed with some serious stuff today, namely directives. There are still a lot of things about directives that we can't possibly cover in a single project. If you like what we've done so far then you're in a good place to keep going. A developer who understands directives well can build a really clean looking code base. Just look at your home.html. It could have just two lines in it. If you're feeling good move on now to Step 7. Step 7. Finishing touches Try to work out these problems on your own. There should be a way to let the user know that the weather data is loading. Something that appears while our $http request is retrieving our data. The $http request shouldn't fire on both opening and closing a user's information. A color change for the currently active user would be nicer than showing that user's info inside the dirWeather modal. Or at least less redundant. Whatever else you want. We still haven't explored transclusion and ng-transclude so give that a try if you're feeling adventurous. Just know that it's a way for deciding where to put the HTML child elements of a directive. It's cool stuff that can involve some criss-crossing of scopes.