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Thursday
Oct102013

In Response to Ben Hilburn

I really enjoyed Ben Hilburn's blog post from the other day. He has a good handle on the field and community, and I particularly liked his constructive criticisms (while I'm used to just criticisms). I wanted to respond to a lot of what he said to make sure that a) it's clear where I'm coming from on many of these issues and b) this is a good conversation to have and continue.

I'm suspicious about the desire for a paradigm shift. I often feel like trying to force that is a mistake and that it will happen when someone comes along with the right new idea. It's kind of like Intel claiming that they embrace disruptive technology and are working to properly direct how they can use it. If you are directing and controlling disruptive technology, I believe you've just landed yourself into a paradox.

As Ben said, he doesn't have the new idea or the new paradigm he'd like to see happen. I'm not entirely convinced that we need a big shift. I'm more excited right now about the idea for new tools that people are talking about and working on (specifically, all of the updates for GRC that were started at the Hackfest). But perhaps I'm so mired in the details of the project right now that I'm missing something in the bigger picture. Yep, I'm completely willing to admit that because there's still so much left that I want to do and so many projects and successes I can see from where we currently are.

Test, Measurement and Display Sinks

I generally agree with most of what Ben is saying here, and it's a large part of why I've been developing QTGUI and trying to push its use. It already addresses many of Ben's issues. I also think it looks better than the WxGUI stuff does, though I admit that it still needs a lot of work there.

I'm somewhat skeptical of trying to go too far in the direction of eye-candy. I agree that aesthetics are important, but they can get too flashy and start to obscure the real point of the plots. Take for instance the Rohde & Schwarz spectrum analyzer picture on Ben's post. What the hell does that even mean? I think they've actually gone overboard with the flash.

The other reason I'm skeptical of this idea is the amount of specialized work required. I'm a huge fan of Sylvain's gr-fosphor efforts, but we couldn't even try it on my laptop because my Sandybridge processor wouldn't support the OpenGL/OpenCL integration work he's done for performance reasons. Rendering these kinds of graphics is intensive and really needs to make use of GPUs, but the tools for generalizing this aren't really there. Just look at the mailing list archives on all the problems that are solved by turning OpenGL off to get a taste.

Still, there's a lot we can do, and I've talked to Balint about some of his work, which is in WxGUI that I would like to see added to QTGUI, instead. Specifically the measurement capabilities. Right now, the QTGUI FFT plots allow you to view the minimum and maximum, but there's very little control over it (like a reset button). Persistence would also be handy, especially in something like the constellation plots to see convergence over time.

Developer Organization

Ben really nailed this one. His idea of integrating the GNU Radio Working Groups (GRWGs) as first-class citizens was, basically, exactly the point. I mentioned this in my previous blog post that the areas identified for the GRWGs are problems that cannot be solved easily or by just one or two developers. We need sustained effort and ideas coming in to identify and execute the “right” solutions.

I'm looking to get a representative or the GRWG leader to report on progress during each monthly Developers' Call we hold (third Thursday of the month). We want to have continuous engagement with the working groups to keep up the momentum and enthusiasm.

Documentation and Theory

I know it's still a problem, but if you go back and look, we've come a long way in the documentation over the past two years. I've tried to provide good documentation for blocks that I'm working on, we're posting the manual's for every version release as well as the output of the weekly developer's builds, one of the GSoC projects integrates the documentation into GRC blocks, and in our efforts for 3.7 we tried to make sure at least the fundamentals for the block's constructor arguments were documented.

Still lots to be done, though. The theory aspect Ben brings up is important and useful, too. Again, I've tried to do this myself, like if you look at the manual pages for the polyphase filterbank blocks. I also try to point to papers and text books that are relevant. But I'm just one developer, and sometimes my efforts while good intentioned don't come out as useful to the end user as I'd like.

The idea of trying to write the theory into the code also helps with what I think is a mandate of open source code (and I might be alone on this). I really believe that one of the things we are doing with GNU Radio is breaking open the black box of communications. While experimentation was a huge part of the beginnings of radio with amateurs radio even being developed as part of the war efforts to make sure the US citizens were well equipped to communicate and organize in case of an attack or disaster. But the past few decades have been more oriented towards standards blocked off in ASICs and RFICs. GNU Radio is one way to break that down and demystify aspects of radio and communication theory. As I said at the conference, learning to transmit and receive BPSK isn't exciting anymore, so why do we keep redeveloping it when we should be pushing into new areas of research and development? Adding the theory into the code to explain what might otherwise be dense or obscure math (for the sake of compilation or runtime efficiency) should be a part of how we code. I'm definitely resolved to to better here.

But here's the problem that I've run into with users submitting documentation. They don't. I agree with Ben that this is an easy win for people to get involved and start contributing. Over the past year, I've had something like eight to ten users tell me that they are working on documentation and would like to contribute it back. I enthusiastically reply back with a “YES PLEASE!” and we start on the road down making them a contributor. And then they disappear.

I'm liking Ben's suggestion to not accept new code without proper documentation. We've not wanted to scare off potential contributors by forcing this, but it's probably time to do it. Ben helped convince me in his post by talking about “high-impact developers,” and he's right. Those are the types of people that recognize the need for comments and documentation and shouldn't be turned off by having it as a requirement.

Other issues

Ben's list of issues are all good ones to tackle. My only significant input here is this: don't run Valgrind against GNU Radio. Or if you do, be prepared for a lot of false positives because of the Python bindings. The rest of his thoughts are good ideas for where to go. We've started with a lot of these and need more people to work and focus on them. For instance, we started working on a gr-liquiddsp project at June's hackfest and the code is posted on github. I point that out to make sure anyone interested in that has a starting place and doesn't duplicate effort.

Reader Comments (2)

Really you think the R&S display is not clear ? Is that based just on the screenshot or did you actually got a chance to play with them ?
Personally I find that this type of color graded persistent display is pretty intuitive when you see it moving and can reveal the signal much more than classical FFTs.

But yeah they're computationally expensive, hence the need for a GPU. Any recent hardware should support it, but unfortunately the driver situation on linux isn't so good and for pretty much all intel GPU, even if the hardware can do it, the driver won't let you. Hope is not entirely lost though, for small bandwidth (like < =10 MHz span), a CPU implementation would probably be viable (it's in the TODO list :)

October 16, 2013 | Unregistered CommenterSylvain Munaut

Hi Sylvain,

I haven't played with that R&S VNA, but I've played with similar from Agilent before. You're right that it's more clear when it's actually moving. You can also adjust the displays, IIRC, and I think that image from Ben's post was them basically turning on everything to make a cooler looking picture. I think there's a balance to be had here where that image is just too busy.

October 31, 2013 | Registered CommenterTom Rondeau
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