Multiheading Linux Systems
Engineering today requires a lot of screen real estate. When you start doing circuit layouts, math models and simulations, image processing and other engineering work, you need room. Plotting the results from two data runs with a package like octave is a common task and is difficult without adequate screen room. We have reached the point where using multiple monitors is pretty much the required baseline in order to work.
Fortunately, the rapid obsolescence of computer hardware has resulted in the early retirement of otherwise good equipment. Who doesn't have an extra video card or monitor lying around that was state of the art a few years ago but has been passed by now? Even if you don't, it doesn't cost much to pick up some new hardware and really spice up your system.
We present a formula to set up a Linux system to have two or more displays in various configurations, some lessons we learned while doing this and some uses we've found for the system. Be forewarned—following this formula doesn't guarantee success because some video cards just won't work with others. As always, please do the appropriate backups before making any system changes.
To set up your system for multiple cards, start with Red Hat 7.2, two video cards and monitors. We begin with a fresh install so you can see each of the steps in case you've already heavily modified your system. (Follow the spirit of these steps if you aren't using Red Hat 7.2 or if you are modifying a working installation.) Again, back up your data before trying any of this.
Physically install both video cards in the system, turn on both monitors and start the Linux installation.
Choose KDE and graphical login when you get to the appropriate part of the installation. This isn't crucial but makes things easier for testing and can be changed later.
Finish the installation and make sure your basic system and the X Window System are working by rebooting and logging in. At this time, you'll have one video card and monitor working.
As root, launch an xterm and make sure you're in your home directory by typing cd. Then type cp /etc/X11/XFConfig-4 . to create a backup copy of your X configuration file in your home directory, just in case.
Now, type telinit 3 to switch from runlevel 5, which uses a graphical login, to runlevel 3 with its console login.
Time to gather some data and see if this is going to work. Log in again as root. Type X -version and note the output. Buried in the output somewhere it will probably say 4.1.0 but could say 3.3.6a, depending on your primary video card. Next is the big step. Type XFree86 -configure and wait for the minute or so that this normally takes to run. Now type XFree86 -xf86config /root/XF86Config.new. If you are successful, you'll hear clicks from both monitors as they switch modes, and the power lights will switch from amber to green. The screens themselves will fill with the raw X display. If they do, congratulations, you should be able to make this setup work (note: kill X by pressing Ctrl-Alt-Backspace). If they don't, then try a different combination of video cards; we couldn't force systems to work that didn't do this step successfully, but we would love to hear about your successes with it! Now type XFree86 -scanpci and record the output. Typical output: (0:8:0) S3 Virge, which is a PCI card, and (1:0:0) NVIDIA Riva Ultra 64, which is an AGP card. Other cards and slots will be identified, but it doesn't matter for this to work.
Configuration of X server: you need to make sure you're calling the right X server, especially if you had an X version less than 4 in step 6. Type ls -l /etc/X11/X. If it is a symbolic link to XFree86, you're using the XFree86 Version 4. If it isn't, back up the link by typing mv /etc/X11/X /etc/X11/X_orig. Make the correct link by typing ln -s /etc/X11/bin/XFree86 /etc/X11/X.
Multihead configuration: at this point, you could just copy the new X configuration file (cp /root/XF86Config.new /etc/X11/XFConfig-4), but your resolution probably wouldn't be very good. A better approach is to edit /etc/X11/XF86Config-4 and incorporate the knowledge gained from going through these steps. We'll cover the fine-tuning in the next section.
Finally, type telinit 5, log in and enjoy. If you're successful, your system will boot up and give you a login screen. The screen on the right is your primary screen; the left screen will come up at the end of the login process.
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