An Interview with Eric Blossom
Eric Blossom's ambitious goal for the GNU Radio project is to "get the software as close to the antenna as is feasible" and turn radio hardware problems into software problems. Check out Eric's article, "GNU Radio: Tools for Exploring the Radio Frequency Spectrum", in the current issue of Linux Journal. In this interview, we catch up with the latest developments for GNU Radio.
Linux Journal: Does the FCC's new Broadcast Flag regulation shut down GNU Radio? Or does a person with the skills to configure and use GNU Radio not count as an "ordinary user"?
Eric Blossom: So far, we think we're okay. The EFF has requested a clarification on our behalf. The crucial word in the rule is "component", and it's not defined. If it means hardware component, then we narrowly are exempt from the requirements. If it means software component, then we've got a problem, and we'll put the lawyers in action.
LJ: Your Web site has a great page about the Universal Software Radio Peripheral (USRP), an experimenter's board that connects to your computer via USB. Will the USRP be able to receive all the modes you cover, including HDTV?
EB: We think we can cover a lot of interesting things, including HDTV. The limitation with the USB approach is the bandwidth we can sustain across the USB. We can sustain 32MB/sec, which should be enough to get the raw or slightly processed HDTV signal across. We expect to be able to access about a 6MHz chuck of the RF spectrum, so a TV channel just fits.
LJ: Are you planning to use GNU Radio as the basis for a wireless mesh network?
EB: There's a lot of interest in that area. In fact, the National Science Foundation has an initiative underway on Programmable Wireless Networking. We've been in communication with a bunch of people in the academic community. A lot of them are enthusiastic about using GNU Radio as the framework for their experimentation. To avoid a duplication of effort, our basic plan is to ensure they [have] whatever infrastructure they need and then to coordinate on the implementation of the various waveforms that would be required for wireless networking.
There are all kinds of interesting problems that need attention, and we think that GNU Radio will serve nicely as a free software platform for research. Folks are looking at wireless networking from all angles and layers: collision free media access layers, dynamic routing of moving nodes, appropriate transport protocols, etc. It turns out that TCP isn't a good transport for wireless. It will run over wireless, but it doesn't work all that well. The characteristics of the medium keep varying in ways that TCP doesn't handle well.
LJ: Do you have a business around GNU Radio as a consultant or hardware supplier?
EB:I've got a business that's primary charter is the support and management of the GNU Radio project. The bulk of my work on GNU Radio is supported by individual and corporate donations made through the Public Software Fund, Inc.
We kind of backed into the hardware project, because nobody else was building what we wanted. At first we looked for existing board manufacturers who would build what we wanted. We found a company and got the initial prototypes built, but then that company was acquired. The new parent didn't think the USRP fit their product line. So at this point, we are considering a variety of options. Putting together a company to build and sell them is one thing we're looking at. Even though the USRP is a free hardware design, unlike free software, somebody's got to take on getting the hardware designed, built, marketed, sold and delivered. It's a bigger problem then releasing tarballs.
Don Marti is Editor in Chief of Linux Journal.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
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With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide