Build a MythTV Box without Breaking the Bank
You may run into a few problems on your low-end system. The two main ones involve high CPU usage and insufficient RAM. You can operate MythTV with 256MB of RAM; however, I experienced frequent freeze-ups, so I upgraded to 512MB. You should keep an eye on how well it's performing and consider upgrading if necessary. Another problem I experienced early on was that playing recordings or DVDs consumed such a large fraction of CPU time (70%–80%), that running other processes tended to cause the playback to become jerky. In particular, commercial flagging and database accesses at the beginning and end of recording a program produced annoying jerkiness. I resolved this problem entirely by replacing my ATI video card, which does not have a proprietary Linux driver, with an NVIDIA card. The skipping stopped almost completely when I replaced the video card, as did the seemingly unrelated problem of slow menu scrolling. CPU usage dropped to around 40%–50%.
Another benefit of NVIDIA's superior Linux support is that part of the MPEG decoding work can be delegated to the video card using XvMC (X-Video Motion Compensation), reducing the load on the CPU. To enable XvMC, go to Utilities/Setup→Setup→TV Settings→Playback. On the third screen, change the Playback Profile to CPU--. XvMC didn't kick in on mine until I deleted the top line of the profile (referring to ivtv). You can tell if it's operating because the on-screen display changes to grayscale. You also can tell because the CPU usage will go way down. The Xorg process dropped to less than 10% during playback; the sum of Xorg and mythfrontend is always less than 30%. As a result, additional processes (including creating and burning DVDs) no longer affected playback.
For a pretty small sum—$85 if you get a tuner card on sale and already have a computer and up to around $500 for a multicard, multidrive system built from scratch—you can build a fully functional MythTV box. TV watching will never be the same.
Be warned: MythTV is an amazing piece of software, but it is free software that is constantly under development. Be prepared to get your hands dirty and tinker under the hood if something goes wrong or everything isn't working as you'd like. Have fun with it—test-drive different themes, tweak the settings and try the various plugins. After all, that's what Linux is all about.
P. Surdas Mohit is a postdoctoral fellow at the Institute of Geophysics and Planetary Physics at Scripps Institute of Oceanography.
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