Has anyone got VOLTTRON running on OS X? I'm trying to assess the effort required to make this happen.
It seems that inotify would need to be replaced with something based on FSEvents. Use of inotify appears to be limited to the volttron.platform.utils.watch_file method so it shouldn't be too difficult.
VOLTTRON does start up without error if I comment out the inotify reference but whatever is dependent on watch_file is certainly not going to work. Are there other libraries or behaviors that would be different or unavailable on OS X? I'm not concerned about hardware/driver interfaces. I don't intend to deploy on OS X but it would be nice to be able to develop on it.
Up until about two years ago we had a developer who was working in OSX and would kindly point out whenever we broke something in his environment.
We haven't really tried it since.
The two places we watch files is for authorization changes at run time. Those features will still work they just won't update state at runtime.
I don't know of any other libraries we use that would stop you from working in OSX.
Related
I am trying to get started developing unittests for my embedded system, actually its a firmware that was already developed a while ago, now we want to add CI to it and start this by writing unittests.
I read blogs like
https://dmitryfrank.com/articles/unit_testing_embedded_c_applications
or https://interrupt.memfault.com/blog/unit-testing-basics and they recommend to implement the unittests via a unittest framework as unity, cpputest and so on and so on. I tried to figure out how to make this run on my windows machine that I use at work but it seems tedious and prone to problems etc.
I also tried to start working with the microsoft vs unit testing framework but got discouraged after running into problems here, too. I think this can't be so hard, it shouldn't take so much effort to start writing the first littlest test...
Do you have experience with this and what would you recommend? Is it viable to do this on Windows? Should I push my boss to let me use a VM, WSL or a Machine that runs Ubuntu? In the end I would like to transfer the CI System to a lab pc (edit: this pc would then also be connected to the hardware, flash it, maybe run a debug build on it and compile some answers that it gets from the hardware... but now I want to talk about the unit test), so if I start developing on Ubuntu now, I will have to deal with this lateron, too...
Maybe a lot of thoughts but I feel a bit overwhelmed with the problem and don't know how to start.
Thanks for you replies, people!
Edit: The discussion I am looking for is not about whether unit testing for embedded systems is useful or the right approach (also interesting but I would like to seperate it) . It's about the question whether it can be fully developed under Windows or whether a Linux System is necessary to be efficient.
I can't figure out how a desktop environment developer test his code. Usually, a C or C++ programmer compiles his code an then run it (i'm not one of those programmers, i'm a web one).
So, you usually build your gui application over some kind of desktop environment (windows, mac os x, gnome, kde, xfce...), sow how they build and test their gui desktop?
And if this is a silly question, how does a kernel programmer test his code? for example linux kernel? how do you know that what you just wrote works?
Testing is a very broad term there are many types (partial list):
unit tests - test small pieces of code. test that the code behaves as expected.
system tests - test whole application in real world scenarios.
performance tests - test what is the performance of the application or part of it.
GUI testing - test operation of GUI elements (not so common as automated tests)
static analysis - compiler warnings on steroids
dynamic analysis - at a minimum memory checks - check mem allocations and usage
coverage tests - check that all code is executed.
formal verification tests (very advanced) - e.g. check when assertions/assumptions are broken.
Kernel code can be debugged by connecting using a 2nd computer (host). Virtual machines uses the same principal and simplify the setup but can't always work as HW might not exist in the guest VM.
The kernel (all OSes) has trace mechanism(s) for printing progress/problems. In Linux the simple trace is shown via the dmesg command (prints a cyclic buffer).
User mode code can easily be stopped and debugged via a debugger.
Desktop Environments
Testing Desktop Environments in real world scenarios can be kind of annoying, so the developer would have to watch out for every small error he makes, if he doesn't, he will have a hard time developing the DE.
As stated by #egur, there are multiple ways of testing his code, the easiest one and most important (but cannot be used in some cases, of course), he can test that code in a simplified program.
A Desktop Environment consists of many parts, however, in your case, I suppose you're talking about the session manager (or window manager) which is responsible for almost everything. So, if he were to test that, he would simply exit his current DE and use the new executable. In case of some error, he can always keep a backup of the old executable or fix the faulty code using some commandline text editor (like vim, or nano).
Kernel
It's quite hard to test, some kernel developers just write some code and make sure it's fine and compiles, then simply let his users test (by ACK'ing the code, etc.), then it can be submitted into the kernel code. Reasoning behind that is, the developer may not have the hardware needed to test the code.
Right now, you can compile and run the kernel in usermode (UML) if you have heard of it, so some developers may go for it. However, some developers may also want to test it themselves (They of course back up the current kernel incase of a screw up).
The way to test a desktop application is related to the way of control the application unassisted or remotely.
The Cross Platform GUI Test Automation tool (I don't know if this project has a web) project helps you to chose the interfaces/libraries required to solve the problem.
In Linux[1] uses the accessibility libraries to control the application, you have Cobra[2] for Windows and PyATOM[3] for MacOS, but I don't know what kind of technology uses in this platforms.
http://ldtp.freedesktop.org/wiki/
https://github.com/ldtp/cobra
https://github.com/pyatom/pyatom
OK, so I recently purchased an Acer T232HL touch screen display to hook up to my Macbook Pro as a secondary monitor. To give you an idea, here's my setup.
OS X doesn't support this monitor in any way, so as you can see in the screenshot I'm actually running Windows 8 through VMware, which proxies the USB connection to Windows perfectly where the touch events are supported. But obviously this isn't ideal.
There's at least one 3rd party driver for OS X that looked sort of promising, but it doesn't seem to support multitouch from this device, it's expensive, and generally was a pain to get working to the small degree it was. There's also mt4j but best I could tell after running their examples, it doesn't support this device at all.
So here's my question: what exactly am I in for if I wanted to write a driver for this thing? I'm mostly a web developer with years of experience with Ruby, Objective-C (and a little C), Javascript, etc. I have never ventured into any kind of hardware programming, so from the surface this feels like an interesting while intimidating challenge.
I know at some level I need to read data from USB. I know this will probably mean trying to reverse engineer whatever protocol they're using for the touch events (is it possible this will be entirely custom?). However I haven't got a clue where to start - would this be a kernel extension? In C, I presume? Would love a high level overview of the moving parts involved here.
Ultimately I want to use the touch screen to drive a specialized web interface (running in Chrome), so ideally I could proxy the touch events straight to Chrome without the OS actually moving the mouse cursor to the touch location (so have the UI behave just as it would on an iPad), but regardless of whether this is technically possible, I'd love to start with just getting something working.
You're going to want to start with Apple's I/O Kit documentation. You can hope that the touchscreen isn't completely custom, though there must be some part that's not standard USB HID, or it would work already. If there are any linux (or other open source) drivers available, you'll have the advantage that somebody already did some of the reverse engineering for you. As an alternative to the I/O Kit, you might also want to look into libusb, which might make your brain hurt less when getting started. If you end up needing to write a kext, that might not help you anymore, though.
As to some of your specific questions:
would this be a kernel extension?
Maybe, maybe not. I'm not really up on the Mac OS X driver situation, but I did write some totally user-space USB code for OS X many years ago. Maybe you'll be as lucky.
In C, I presume?
Probably. I/O Kit itself is written in a subset of C++, so you can probably use that too, if you prefer.
is it possible this will be entirely custom?
Unfortunately, yes, it's possible.
Good luck!
I have written an application in C, which runs as a Windows service. Most users can run the app without any problems, but a significant minority experience crashes caused by an Access Violation, so I know I have a bug somewhere. I have tried setting up virtual machines to mirror the users' configurations as closely as possible, but cannot reproduce the issue.
My background is in Java - when a Java app crashes it will produce a stack trace showing exactly where the problem occurred, but native applications aren't so helpful. What techniques are normally used by C developers for tracking down this type of problem? I have no physical access to the users' machines that experience the crash, but I could send then additional tools to install, to capture information. I also have Windows error reports showing Exception Code/Offset etc but these don't mean much to me. I have compiled my application using gcc - are there some compiler options I can use to generate more information in the event of a crash?
You could try asking the users to run ProcDump to capture a core dump when the program crashes. Unlike using something like Visual Studio it's a single, simple command-line utility so there should be no problem getting the users to run it.
On most modern operating systems your app can install a crash handler that'll walk the stack(s) in the event of a crash. I have no experience doing this on Windows, but this article walks through how to do it.
Is there a way I can create a virtual instance of gcc compiler on the client browser when the client opens my website??
By doing so, I can directly pass the user .c file as argument to my compiler instance and then execute it without having to make a POST call to server and execute the file there???
Originally I userstood your question to be targeting the native platform on which the browser is running:
Consider that Browsers may be running
on many different platforms,
operatinng systems and processor
architectures. Compiling C in the way
you describe might be technically
doable, but practically infeasible.
I was basing "practically infeasible" on the difficulty of supporting the plethora of widely used browser platforms.
Now I understand that you are thinking more on the lines of targeting a virtual environment. I'll amend practically infeasible to "a large amount of work".
If I understand your intent it is to run a C compiler which emits, shall we say, x86 compiled code and executes it. So to do that we need an emulation of the x86 environment in, say, JavaScript. What's more I think your intent is that the conmpiler itself execute in this environment, so that you can re-use gcc. So you'll need to emulate a file-system too. It's "obvious" that this could be done, but it really is a lot of work. Is it really worth it?
Competition code is small (I guess) even with lots of programmers the number of simultaneous compiles can't be so huge with a decent queued request system, a touch of Ajax, and a bit of back-end scaling how costly is it to support the expected population? What's the ratio of developers to back end systems?
Anyway, if I were to address this problem I'd go for taking the code for an opensource browser and melding in the gcc code. Produce a compiler/browser hybrid. Give that to the developers and tell them "Use this and get zippy compilation speeds, or use your own browser and join the queue."
You're not going to use GCC as it is written for this. AT BEST, you could accomplish something simalar if you had a compiler written in Java that targeted the JVM and could be ran as an applet. I don't know what it would take to get something like this working but, I suspect it would take a bit work to get it up and going. As far as I know nothing currently exist that does this.
Perhaps using a jsLinux in background? There the making process can run in the virtual machine. Communication could be done by extending the clipboard transfer, perhaps into multiple pipes...
I would be interested in javascript based gcc solutions, too.