Some kernel options should be activated for optimizing DVD playback. I strongly urge the application of Andrew Morton's low-latency patches, and it also may be advisable to apply Robert Love's preemptive kernel patch. The combination of these patches provides very low latency (below 3msecs) over sustained periods of time. My kernel of choice is currently 2.4.18, but Andrew's and Robert's patches are available for a variety of kernel releases (see Resources for more information).
You also should make sure your kernel has enabled support for the RTC and MTRR options (found under the Character devices and Processor type and features kernel configuration sections, respectively). RTC provides access to the real-time hardware clock of your PC. According to the kernel configuration help file, all PCs have such a clock but it is not enabled by the default kernel configuration. Although it is not absolutely required, many Linux audio and video applications can utilize this clock for a finer timing response (MPlayer likes it), so I suggest building it directly into your kernel or as a dynamically loadable module.
According to the kernel configuration help, enabling the MTRR (memory type range registers) provides a mechanism that is used:
...to control processor access to memory ranges. This is most useful if you have a video (VGA) card on a PCI or AGP bus. Enabling write-combining allows bus write transfers to be combined into a larger transfer before bursting over the PCI/AGP bus. This can increase performance of image write operations 2.5 times or more.
So, if you have a PCI or AGP video card you will want to enable this option.
Under the ATA/IDE/MFM/RLL Support section, I advise enabling the options for generic PCI bus-master DMA support and the use of PCI DMA by default.
The last step is to configure sound support for your hardware. I use the ALSA sound system, so all I do is enable sound card support in the kernel options. The ALSA drivers are built in normal user space and installed as root as loadable kernel modules. You safely can use the available kernel modules instead of ALSA, but in my opinion the ALSA drivers are superior. In fact, ALSA will become the de facto kernel sound system for Linux kernels beyond the 2.5.x series.
I began my tests with XFree86 4.1.0. Everything seemed to work fine except for an annoying problem with xine: after closing that player my X server would unceremoniously crash, dumping me back at the console prompt. When I upgraded to XFree86 4.3.0 and the latest driver for my GeForce2 from NVIDIA (1.0-4363), all problems were resolved. Because XFree86 4.3.0 fixes a number of problems and bugs found in the earlier versions, I suggest the upgrade to anyone using any of these players, not only xine. And, if you're using an NVIDIA card you always should use their latest drivers.
As mentioned earlier, XFree86 provides a video output driver called Xv, but other drivers are available for the frame-buffer device, SDL (Simple DirectMedia Layer) video output and X11/Xshm. The driver you select affects playback performance. Xv normally is preferred, but you can experiment with whatever drivers are supported by your player of choice for the best output.
My X environment also includes the Blackbox window manager. I prefer simple and fast, and Blackbox fits the bill for me. Be advised that your DVD-viewing mileage may vary in part due to your window manager or desktop environment of choice, and you may need to adjust your available video resources accordingly.
It may come as a surprise to learn that you can tune your DVD and CD-ROM drives as easily as you can tune your hard disks. The hdparm utility can optimize drive performance to peak efficiency, run it (as root) with at least the following parameter options:
hdparm -c1 -d1 -a8 -u1 /dev/hdd
where -c1 enables 32-bit I/O, -d1 enables DMA access, -a8 sets the filesystem read-ahead value and -u1 sets the drive's interrupt-unmask flag. /dev/hdd should specify your particular DVD drive device location.
The parameters shown above work well with my DVD drive, but I urge you to read the hdparm manual page (man hdparm) before running the utility. Your DVD drive is a read-only device, so filesystem corruption is not an issue here. You might, however, inadvertently lower your drive's efficiency with non-optimal settings.
It has been brought to my attention that Red Hat 8.0 users have reported difficulties enabling DMA on their DVD drives. If you're running that distribution, add the following line to your /etc/modules.conf to fix the problem:
options ide-cd dma=1
Similis sum folio de quo ludunt venti.
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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- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- SuperTuxKart 0.9.2 Released
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- Doing for User Space What We Did for Kernel Space
- Parsing an RSS News Feed with a Bash Script
- SourceClear Open
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