Over-the-Air Digital TV with Linux
My ten-year-old TV set gave out recently. Being a Linux geek, I use a variety of open-source distributions on my notebook and desktop. So, the demise of my TV was a great opportunity to see if I could watch television on Linux instead of getting another TV set. It's just in time too, because over-the-air television broadcasts in the US will convert to all digital in February 2009. So, it was exciting to switch over to digital TV on my desktop.
In my quest to understand the state of digital TV (DTV) on Linux, I looked at digital TV tuner cards, antennas and accessories. I chose to set up MythTV, and by the end of the entire experience, I had a cool digital TV right on my Linux desktop with Picture-in-Picture and remote control. It was enough high-definition (HD) TV to turn me into a serious couch potato. I'm happy to report that Linux, along with hardware support from digital TV tuner cards, video cards, LCD monitors and rich software, such as MythTV, is ready for prime time.
For this review, I used a PC with an Intel Core 2 Duo 3GHz, with 4GB memory, an NVIDIA 8800 GT graphics card, and a 750GB SATA hard disk. The display was a Samsung SyncMaster 245BW, with a resolution of 1920x1200. I ran Ubuntu 7.10, with all the latest updates, as my operating system. Using a powerful graphics card was essential for viewing HD programs on a high-resolution, wide-screen display.
A good antenna also is a critical component of the DTV setup. I tested both indoor and outdoor antennas, and discovered that the reception improved dramatically when using an outdoor antenna. The reception also improved with amplified indoor antennas. Standard indoor antennas performed adequately only when positioned very carefully. Because HDTV content is high-resolution (1920x1080), if your signal is weak, you may see a lot of artifacts. Frequent artifacts result in a very poor viewing experience. Hence, choosing an amplified indoor antenna or an outdoor antenna is recommended. Standard-definition TV (SDTV) is not as high-resolution and has greater tolerance for weak broadcast signals. But, even here a good antenna is essential.
I used MythTV (version 0.20.2) to view over-the-air DTV channels. MythTV is an open-source home entertainment software application for Linux and Mac OS. It has grown to become one of the most comprehensive, feature-rich platforms for viewing and recording television programming from over-the-air and cable broadcasts. I also used another open-source software application called tvtime (version 1.0.2) to view over-the-air analog NTSC channels.
So, what can we watch? There are a lot of over-the-air programs available in all major US metropolitan areas. For example, ABC, CBS, FOX and NBC offer standard and high-definition programming in addition to analog NTSC. In my location, the San Francisco Bay area, local public broadcasting stations (PBS) broadcast high-quality educational and topical content in HDTV format from 5pm to 6am each day.
To evaluate various digital tuner cards, I tested first whether the hardware was recognized by Linux at boot time by checking the system logs. If it wasn't recognized, I had to find and build a device driver manually. Once this step was successful, I configured the tuner card within MythTV. As a part of configuration, MythTV scans for channels available in the broadcast area. On average, it took MythTV about seven minutes to find more than 25 digital channels. Once the channels were found, we were ready to watch digital TV.
I evaluated a range of digital tuners that included PCI, PCI Express and USB bus types.
The pcHDTV HD-5500 is a PCI card and is the only hardware designed and marketed to support Linux right out of the box. The HD-5500 supports digital (ATSC), analog (NTSC) and unencrypted cable TV signals. This low-profile PCI card provides a coaxial input for a TV antenna, a stereo audio output jack for analog TV and a nine-pin port for an adapter cable. The adapter cable provides inputs for S-Video and stereo audio, an RCA video output, and an IR transmitter (to control a set-top box). pcHDTV ships a CD with the HD-5500 tuner card, which includes drivers for 2.4 and older 2.6 kernels, command-line tools to capture and manipulate digital (ATSC) data streams and signals, and a version of the Xine video player customized to support HDTV.
This tuner card worked out of the box—configuration was as easy as installing the card into the PCI slot of my desktop test machine. Both the digital (ATSC) and analog (NTSC) tuners on the hardware were recognized right away and were fully functional at system bootup. Configuring the tuner as a “DVB DTV capture card (v3.x)” in MythTV was simple. If I had installed additional pcHDTV cards, I could have tested out multicard features, such as Picture-in-Picture (PiP) in MythTV. pcHDTV claims you can put up to four such cards in a single system.
The picture quality for both high-definition and standard-definition programs was superb. To top it off, the whole idea of having an end-to-end Linux DTV solution with a no-fuss setup and a great viewing experience is just plain cool. The HD-5500 is an ideal choice for a desktop Linux system. It would be nice to have a USB version for laptops as well. A remote control, as offered by several other DTV tuner products, would be icing on the cake.
I had the chance to catch up with pcHDTV's CEO, Jack Kelliher, by e-mail (see the Interview with Jack Kelliher, CEO and Cofounder of pcHDTV sidebar).
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.
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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