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    <title>RTXI</title>
    <description>RTXI is a fast, open-source system for hard real-time, closed-loop data acquisition and stimulation for electrophysiology experiments.</description>
    <link>http://rtxi.org</link>
    <atom:link href="http://rtxi.org/feed.xml" rel="self" type="application/rss+xml" />
    
      <item>
        <title>RTXI 3.0.0 Released!</title>
        <description>&lt;p&gt;RTXI v3.0.0 is now available&lt;/p&gt;

&lt;p&gt;This release modernizes RTXI architecture and leverages newer techniques on performance and maintainability patterns.&lt;/p&gt;

&lt;p&gt;The need for these updates originates primarily from the difficulty of updating RTXI 2.4 to the new Xenomai API, as well as the unfortunate news that the Analogy drivers used for hardware access would not be supported any longer under Xenomai. These and other architectural issues made it necessary to apply the lessons learned from years of use to improve software architecture and flexibility. This update relies on proven methods, and uses existing code to create a modern RTXI application. Some of the changes introduced:
New Functionality&lt;/p&gt;

&lt;div class=&quot;language-plaintext highlighter-rouge&quot;&gt;&lt;div class=&quot;highlight&quot;&gt;&lt;pre class=&quot;highlight&quot;&gt;&lt;code&gt;- New abstractions that reduces user and developer cognitive load
- Introduces a new scheduler and connector classes for faster and more accurate plugin real-time scheduling
- A redesign of the event system to have stronger typing and safer abstractions
- Support for the newest Xenomai framework now called EVL
- Introduction of new DAQ driver model to support non Analogy devices
- Support for National Instruments DAQ PCIe devices
- Introduction of the Real-Time Platform Abstraction Layer (RTPAL) for non Xenomai real-time support
- Automatic driver and real-time platform detection scheme for ease of use
- Central logging system to capture events fired by RTXI components and plugins
- Retire the DefaultGuiModel classes and introduction of the widget classes (plugin, component, and panel)
- Migration from autotools build system to cmake
- Update to installation instructions for both main RTXI components and DSO plugins
- Major updates to the builtin plugins such as data recorder and oscilloscope
- and many more
&lt;/code&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;

&lt;p&gt;You can download the new version at the repository and run the install_rtxi.sh script. Test it out and let us know what you think.&lt;/p&gt;

&lt;p&gt;Happy sciencing!&lt;/p&gt;
</description>
        <pubDate>Thu, 30 Nov 2023 00:00:00 -0500</pubDate>
        <link>http://rtxi.org//news/2023/11/30/rtxi-300-released/</link>
        <guid isPermaLink="true">http://rtxi.org//news/2023/11/30/rtxi-300-released/</guid>
      </item>
    
      <item>
        <title>RTXI 2.3 Release</title>
        <description>&lt;p&gt;A new version of RTXI is now available!&lt;/p&gt;

&lt;p&gt;New features include:&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;&lt;strong&gt;Support for New Linux LTS Base&lt;/strong&gt;: Now RTXI 2.3 runs on Ubuntu 20.04 LTS.&lt;/li&gt;
  &lt;li&gt;&lt;strong&gt;Support for Xenomai 3.1&lt;/strong&gt;: RTXI can now be installed with Xenomai 3.1; A newer version of the real-time framework.&lt;/li&gt;
  &lt;li&gt;&lt;strong&gt;Minor Bug fixes&lt;/strong&gt;: for improved stability and long term maintenance&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Along with the newer version of rtxi there are also updated installation steps and website contact
information. Let us know if you have any issues installing RTXI by emailing us at &lt;a href=&quot;mailto:help@rtxi.org&quot;&gt;help@rtxi.org&lt;/a&gt;&lt;/p&gt;
</description>
        <pubDate>Thu, 22 Jul 2021 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//news/2021/07/22/rtxi-v23-release/</link>
        <guid isPermaLink="true">http://rtxi.org//news/2021/07/22/rtxi-v23-release/</guid>
      </item>
    
      <item>
        <title>Getting Started</title>
        <description>&lt;p&gt;To get started with RTXI for your experiments, there are some hardware
requirements you need to satisfy.  They’re pretty easy to meet, and they’ll get
you set up with a properly performing RTXI installation.&lt;/p&gt;

&lt;p&gt;If you are not familiar with RTXI or what it can do, we recommend looking
through the &lt;a href=&quot;/manual&quot;&gt;manual&lt;/a&gt; first.&lt;/p&gt;

&lt;p&gt;You will need:&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;Computer&lt;/li&gt;
  &lt;li&gt;Data acquisition card (DAQ)&lt;/li&gt;
  &lt;li&gt;Graphics card (may come with computer)&lt;/li&gt;
&lt;/ol&gt;

&lt;h4 id=&quot;computer&quot;&gt;Computer&lt;/h4&gt;
&lt;p&gt;Most computers built in the last few years will run Linux, but some will
perform better for real-time applications. Here are some points to consider
when buying new hardware:&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;&lt;strong&gt;What is the CPU type?&lt;/strong&gt; We recommend using Intel processors, though AMD
ones work, too.&lt;/li&gt;
  &lt;li&gt;&lt;strong&gt;How many PCI/PCIe slots are there?&lt;/strong&gt; Most computers now come with only PCIe
slots, so make sure to get a PCIe compatible DAQ card. Currently RTXI only
supports National Instrument DAQ cards.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Also, you should have a machine with at least &lt;strong&gt;4 GB of RAM&lt;/strong&gt;. While Linux can
run with less, you will see degraded performance. Over the past few years,
operating systems have been built under the assumption of increasingly capable
hardware, and Linux has been no exception.&lt;/p&gt;

&lt;h4 id=&quot;daq&quot;&gt;DAQ&lt;/h4&gt;
&lt;p&gt;RTXI is tested and developed on systems using National Instruments (NI) cards.
The Xenomai project may still support PCI cards, but not PCIe, and we
do not test them so we cannot give you a recommendation to use them. Instead we 
advice downloading and installing the NIDAQmx library, which supports a wide 
range of National Instruments DAQ cards and is the interface used by RTXI. Here are
a list of resources for downloading and installing NIDAQmx:&lt;/p&gt;

&lt;ul&gt;
  &lt;li&gt;&lt;a href=&quot;https://www.ni.com/en/support/downloads/drivers/download.ni-daq-mx.html&quot;&gt;&lt;strong&gt;Download NIDAQmx&lt;/strong&gt;&lt;/a&gt;&lt;/li&gt;
  &lt;li&gt;&lt;a href=&quot;https://www.ni.com/docs/en-US/bundle/ni-platform-on-linux-desktop/page/installing-ni-drivers-and-software-on-linux-desktop.html&quot;&gt;&lt;strong&gt;Installation Instructions for NIDAQmx in Linux&lt;/strong&gt;&lt;/a&gt;&lt;/li&gt;
  &lt;li&gt;&lt;a href=&quot;https://www.ni.com/en/support/documentation/compatibility/21/ni-hardware-and-operating-system-compatibility.html&quot;&gt;&lt;strong&gt;DAQ driver and operating system compatibility&lt;/strong&gt;&lt;/a&gt;&lt;/li&gt;
&lt;/ul&gt;

&lt;h4 id=&quot;graphics-card&quot;&gt;Graphics Card&lt;/h4&gt;
&lt;p&gt;&lt;strong&gt;NOTE:&lt;/strong&gt; The information in this section was compiled over a decade ago, and a
lot has changed since then. Nvidia now provides better support for linux drivers.
Research whether your graphics card has driver support for linux.&lt;/p&gt;

&lt;p&gt;You should get a discrete graphics card. Using integrated graphics will cause
UI computation to be offloaded to the CPU, which at the same time has to handle
real-time processes. Based on the systems we’ve benchmarked so far, you’re
better off using an AMD card than an Nvidia one. You are also recommended to
use open-source drivers instead of their proprietary counterparts.&lt;/p&gt;

&lt;p&gt;What this means for you is that when buying/acquiring a computer, you need to
check the type of graphics card it has. You also need to check whether it is
supported by open-source drivers. (Often, newer hardware needs some time for
the people who code the drivers to extend support for them.)&lt;/p&gt;

&lt;p&gt;Here is a list of graphics card supported by the Nvidia open-source driver
(nouveau) and the AMD one (radeon):&lt;/p&gt;

&lt;ul&gt;
  &lt;li&gt;&lt;a href=&quot;https://help.ubuntu.com/community/RadeonDriver#Fully_Supported&quot;&gt;&lt;strong&gt;AMD driver (radeon)&lt;/strong&gt;&lt;/a&gt;&lt;/li&gt;
  &lt;li&gt;&lt;a href=&quot;https://wiki.freedesktop.org/nouveau/FAQ/#index14h3&quot;&gt;&lt;strong&gt;Nvidia driver (nouveau)&lt;/strong&gt;&lt;/a&gt;&lt;/li&gt;
&lt;/ul&gt;

&lt;h3 id=&quot;installing-rtxi&quot;&gt;Installing RTXI&lt;/h3&gt;

&lt;p&gt;Look through our &lt;a href=&quot;/install&quot;&gt;installation instructions&lt;/a&gt; to see how to install
RTXI 3.0.0. If you run into issues, look through our 
available &lt;a href=&quot;/docs&quot;&gt;documentation&lt;/a&gt;, and if it doesn’t help, email us or 
&lt;a href=&quot;https://github.com/rtxi/rtxi/issues&quot;&gt;submit an issue on GitHub&lt;/a&gt;. We recommend 
you do the latter.&lt;/p&gt;

&lt;h4 id=&quot;note&quot;&gt;Note&lt;/h4&gt;

&lt;p&gt;&lt;a href=&quot;https://github.com/rtxi/rtxi.github.io/issues/&quot;&gt;Let us know&lt;/a&gt; if any links are
broken.  They are all supposed to point directly to lists of hardware
compatible with drivers.  If they don’t, something went terribly wrong, and we
need to fix the links.&lt;/p&gt;
</description>
        <pubDate>Wed, 01 Jan 2020 00:00:00 -0500</pubDate>
        <link>http://rtxi.org//docs/tutorials/2020/01/01/getting-started/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/tutorials/2020/01/01/getting-started/</guid>
      </item>
    
      <item>
        <title>RTXI 2.2 Released</title>
        <description>&lt;p&gt;New version with long-term support and a new real-time kernel!&lt;/p&gt;

&lt;p&gt;New features:&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;&lt;strong&gt;New Linux Base&lt;/strong&gt;: RTXI 2.2 runs on Ubuntu GNOME 16.04 LTS - with it, you’ll get a stable desktop with hardware and software support for the next few years through Ubuntu and the RTXI team.&lt;/li&gt;
  &lt;li&gt;&lt;strong&gt;Enhanced Performance&lt;/strong&gt;: We’ve upgraded to the latest version of Xenomai - which includes a number of under-the-hood updates to the real-time system, but still the same robust performance.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Try out v2.2. You can use the live CD to demo RTXI and later install it, or you can install a generic Linux distribution of your choice and use our installation scripts. We’ve included two different live CDs - one for Core 2/Newer Xeon processors and one for generic x64 processors.&lt;/p&gt;

&lt;p&gt;Look through all the documentation on the website to find installation instructions, notes on hardware configurations, RTXI modules, documentation, and more. Let us know if you have issues or questions.&lt;/p&gt;
</description>
        <pubDate>Tue, 09 Jan 2018 00:00:00 -0500</pubDate>
        <link>http://rtxi.org//news/2018/01/09/rtxi-v22-released/</link>
        <guid isPermaLink="true">http://rtxi.org//news/2018/01/09/rtxi-v22-released/</guid>
      </item>
    
      <item>
        <title>Technical overview of RTXI</title>
        <description>&lt;p&gt;Ever been curious about how RTXI works? Check out the new paper recently published in PLOS Computational Biology:&lt;/p&gt;

&lt;p&gt;&lt;a href=&quot;http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1005430&quot;&gt;Patel, Y.A., George, A., Dorval, A.D., White, J.A., Christini, D.J. and Butera, R.J., 2017. Hard real-time closed-loop electrophysiology with the Real-Time eXperiment Interface (RTXI). PLOS Computational Biology, 13(5), p.e1005430.&lt;/a&gt;&lt;/p&gt;
</description>
        <pubDate>Thu, 01 Jun 2017 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//news/2017/06/01/paper-published/</link>
        <guid isPermaLink="true">http://rtxi.org//news/2017/06/01/paper-published/</guid>
      </item>
    
      <item>
        <title>Kilohertz frequency nerve block enhances anti-inflammatory effects of vagus nerve stimulation</title>
        <description>&lt;p&gt;Efferent activation of the cervical vagus nerve (cVN) dampens systemic inflammatory processes, potentially modulating a wide-range of inflammatory pathological conditions. In contrast, afferent cVN activation amplifies systemic inflammatory processes, leading to activation of the hypothalamic-pituitary-adrenal (HPA) axis, the sympathetic nervous system through the greater splanchnic nerve (GSN), and elevation of pro-inflammatory cytokines. Ideally, to clinically implement anti-inflammatory therapy via cervical vagus nerve stimulation (cVNS) one should selectively activate the efferent pathway. Unfortunately, current implementations, in animal and clinical investigations, activate both afferent and efferent pathways. We paired cVNS with kilohertz electrical stimulation (KES) nerve block to preferentially activate efferent pathways while blocking afferent pathways. Selective efferent cVNS enhanced the anti-inflammatory effects of cVNS. Our results demonstrate that: (i) afferent, but not efferent, cVNS synchronously activates the GSN in a dose-dependent manner; (ii) efferent cVNS enabled by complete afferent KES nerve block enhances the anti-inflammatory benefits of cVNS; and (iii) incomplete afferent KES nerve block exacerbates systemic inflammation. Overall, these data demonstrate the utility of paired efferent cVNS and afferent KES nerve block for achieving selective efferent cVNS, specifically as it relates to neuromodulation of systemic inflammation.&lt;/p&gt;
</description>
        <pubDate>Thu, 05 Jan 2017 00:00:00 -0500</pubDate>
        <link>http://rtxi.org//papers/2017/01/05/kilohertz-frequency-nerve-block-enhances-anti-inflammatory-effects-of-vagus-nerve-stimulation/</link>
        <guid isPermaLink="true">http://rtxi.org//papers/2017/01/05/kilohertz-frequency-nerve-block-enhances-anti-inflammatory-effects-of-vagus-nerve-stimulation/</guid>
      </item>
    
      <item>
        <title>Illuminating Myocyte-Fibroblast Homotypic and Heterotypic Gap Junction Dynamics Using Dynamic Clamp</title>
        <description>&lt;p&gt;Fibroblasts play a significant role in the development of electrical and mechanical dysfunction of the heart; however, the underlying mechanisms are only partially understood. One widely studied mechanism suggests that fibroblasts produce excess extracellular matrix, resulting in collagenous septa that slow propagation, cause zig-zag conduction paths, and decouple cardiomyocytes, resulting in a substrate for cardiac arrhythmia. An emerging mechanism suggests that fibroblasts promote arrhythmogenesis through direct electrical interactions with cardiomyocytes via gap junction (GJ) channels. In the heart, three major connexin (Cx) isoforms, Cx40, Cx43, and Cx45, form GJ channels in cell-type-specific combinations. Because each Cx is characterized by a unique time- and transjunctional voltage-dependent profile, we investigated whether the electrophysiological contributions of fibroblasts would vary with the specific composition of the myocyte-fibroblast (M-F) GJ channel. Due to the challenges of systematically modifying Cxs in vitro, we coupled native cardiomyocytes with in silico fibroblast and GJ channel electrophysiology models using the dynamic-clamp technique. We found that there is a reduction in the early peak of the junctional current during the upstroke of the action potential (AP) due to GJ channel gating. However, effects on the cardiomyocyte AP morphology were similar regardless of the specific type of GJ channel (homotypic Cx43 and Cx45, and heterotypic Cx43/Cx45 and Cx45/Cx43). To illuminate effects at the tissue level, we performed multiscale simulations of M-F coupling. First, we developed a cell-specific model of our dynamic-clamp experiments and investigated changes in the underlying membrane currents during M-F coupling. Second, we performed two-dimensional tissue sheet simulations of cardiac fibrosis and incorporated GJ channels in a cell type-specific manner. We determined that although GJ channel gating reduces junctional current, it does not significantly alter conduction velocity during cardiac fibrosis relative to static GJ coupling. These findings shed more light on the complex electrophysiological interplay between cardiac fibroblasts and myocytes.&lt;/p&gt;
</description>
        <pubDate>Tue, 23 Aug 2016 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//papers/2016/08/23/illuminating-myocyte-fibroblast-homotypic-and-heterotypic-gap-junction-dynamics-using-dynamic-clamp/</link>
        <guid isPermaLink="true">http://rtxi.org//papers/2016/08/23/illuminating-myocyte-fibroblast-homotypic-and-heterotypic-gap-junction-dynamics-using-dynamic-clamp/</guid>
      </item>
    
      <item>
        <title>Cell-specific Dynamic Clamp analysis of the role of funny I f current in cardiac pacemaking</title>
        <description>&lt;p&gt;We used the Dynamic Clamp technique for i) comparative validation of conflicting computational models of the hyperpolarization-activated funny current, If, and ii) quantification of the role of If in mediating autonomic modulation of heart rate. Experimental protocols based on the injection of a real-time recalculated synthetic If current in sinoatrial rabbit cells were developed.&lt;/p&gt;

&lt;p&gt;Preliminary results of experiments mimicking the autonomic modulation of If demonstrated the need for a customization procedure to compensate for cellular heterogeneity. For this reason, we used a cell-specific approach, scaling the maximal conductance of the injected current based on the cell’s spontaneous firing rate. The pacemaking rate, which was significantly reduced after application of Ivabradine, was restored by the injection of synthetic current based on the Severi-DiFrancesco formulation, while the injection of synthetic current based on the Maltsev-Lakatta formulation did not produce any significant variation. A positive virtual shift of the If activation curve, mimicking the Isoprenaline effects, led to a significant increase in pacemaking rate (+17.3 ± 6.7%, p &amp;lt; 0.01), although of lower magnitude than that induced by real Isoprenaline (+45.0 ± 26.1%). Similarly, a negative virtual shift of the activation curve significantly lowered the pacemaking rate (−11.8 ± 1.9%, p &amp;lt; 0.001), as did the application of real Acetylcholine (−20.5 ± 5.1%).&lt;/p&gt;

&lt;p&gt;The Dynamic Clamp approach, applied to the If study in cardiomyocytes for the first time and rate-adapted to manage intercellular variability, indicated that: i) the quantitative description of the If current in the Severi-DiFrancesco model accurately reproduces the effects of the real current on rabbit sinoatrial cell pacemaking rate and ii) a significant portion (50–60%) of the physiological autonomic rate modulation is due to the shift of the If activation curve.fferent activation of the cervical vagus nerve (cVN) dampens systemic inflammatory processes, potentially modulating a wide-range of inflammatory pathological conditions. In contrast, afferent cVN activation amplifies systemic inflammatory processes, leading to activation of the hypothalamic-pituitary-adrenal (HPA) axis, the sympathetic nervous system through the greater splanchnic nerve (GSN), and elevation of pro-inflammatory cytokines. Ideally, to clinically implement anti-inflammatory therapy via cervical vagus nerve stimulation (cVNS) one should selectively activate the efferent pathway. Unfortunately, current implementations, in animal and clinical investigations, activate both afferent and efferent pathways. We paired cVNS with kilohertz electrical stimulation (KES) nerve block to preferentially activate efferent pathways while blocking afferent pathways. Selective efferent cVNS enhanced the anti-inflammatory effects of cVNS. Our results demonstrate that: (i) afferent, but not efferent, cVNS synchronously activates the GSN in a dose-dependent manner; (ii) efferent cVNS enabled by complete afferent KES nerve block enhances the anti-inflammatory benefits of cVNS; and (iii) incomplete afferent KES nerve block exacerbates systemic inflammation. Overall, these data demonstrate the utility of paired efferent cVNS and afferent KES nerve block for achieving selective efferent cVNS, specifically as it relates to neuromodulation of systemic inflammation.&lt;/p&gt;
</description>
        <pubDate>Mon, 21 Dec 2015 00:00:00 -0500</pubDate>
        <link>http://rtxi.org//papers/2015/12/21/cell-specific-dynamic-clamp-analysis-of-the-role-of-funny-if-current-in-cardiac-pacemaking/</link>
        <guid isPermaLink="true">http://rtxi.org//papers/2015/12/21/cell-specific-dynamic-clamp-analysis-of-the-role-of-funny-if-current-in-cardiac-pacemaking/</guid>
      </item>
    
      <item>
        <title>RTXI Fall Newsletter</title>
        <description>&lt;p&gt;There have been lots of new developments in RTXI over the past few months. Look
forward to the upcoming release of RTXI 2.1, and we encourage those of you
attending SfN 2015 to check out our poster!&lt;/p&gt;

&lt;h4 id=&quot;upcoming-features-in-rtxi-21&quot;&gt;Upcoming Features in RTXI 2.1&lt;/h4&gt;

&lt;ul&gt;
  &lt;li&gt;
    &lt;p&gt;&lt;strong&gt;New Plotting Tools&lt;/strong&gt; - We’ve created a new analysis-tools module that will
directly plot HDF data saved by the data recorder.&lt;/p&gt;
  &lt;/li&gt;
  &lt;li&gt;
    &lt;p&gt;&lt;strong&gt;UI Upgrades&lt;/strong&gt; - We’ve upgraded RTXI’s UI framework from Qt4 to Qt5, the
most up-to-date version available.&lt;/p&gt;
  &lt;/li&gt;
  &lt;li&gt;
    &lt;p&gt;&lt;strong&gt;Bugfixes and Tweaks&lt;/strong&gt; - RTXI is continually improving under the hood, and
for 2.1, we bundled in lots of bugfixes, UI tweaks, and performance
  enhancements.&lt;/p&gt;
  &lt;/li&gt;
  &lt;li&gt;
    &lt;p&gt;&lt;strong&gt;Improved User-friendliness&lt;/strong&gt; - RTXI now checks for updates, and the new
module-installer makes finding and installing the modules you need easier
than ever.&lt;/p&gt;
  &lt;/li&gt;
  &lt;li&gt;
    &lt;p&gt;&lt;strong&gt;Arduino Support&lt;/strong&gt; - The new Arduino module provides an interface between
RTXI and Arduino computers. Note that this is non-RT.&lt;/p&gt;
  &lt;/li&gt;
  &lt;li&gt;
    &lt;p&gt;&lt;strong&gt;New Module Installer&lt;/strong&gt; - A new Module Installer allows you to find and
install modules within RTXI itself.&lt;/p&gt;
  &lt;/li&gt;
&lt;/ul&gt;

&lt;h4 id=&quot;check-us-out-at-sfn&quot;&gt;Check us out at SfN:&lt;/h4&gt;

&lt;p&gt;We’ll be presenting a poster at this year’s Society for Neuroscience
Conference. If you’re also attending, feel free to stop by. Look out for poster
267.23 / BB66 during the 1:00 -5 :00 PM session on October 18. We’ll be in Hall
A.&lt;/p&gt;

&lt;h4 id=&quot;contact-us&quot;&gt;Contact Us:&lt;/h4&gt;

&lt;p&gt;You can reach out to us via email and through GitHub. Let us know if you have
any questions or issues. We’re around 24/7, and we’ll do whatever we can to get
RTXI working for you. We’ll even come to you in person.&lt;/p&gt;
</description>
        <pubDate>Fri, 09 Oct 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//news/2015/10/09/fall-newsletter/</link>
        <guid isPermaLink="true">http://rtxi.org//news/2015/10/09/fall-newsletter/</guid>
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      <item>
        <title>IKr Impact on Repolarization and Its Variability Assessed by Dynamic-Clamp</title>
        <description>&lt;p&gt;Repolarization and its stability are exquisitely sensitive to IKr features. Information on the relative importance of specific IKr abnormalities is missing and would assist in the evaluation of arrhythmogenic risk.&lt;/p&gt;

&lt;p&gt;In single guinea-pig myocytes, endogenous IKr was replaced by modelled IKr (mIKr) by Dynamic-Clamp (DC) at a cycle length of 1 s. mIKr parameters were systematically modified and the resulting changes in action potential duration (APD) and its short term variability (SD1) were measured. We observed that: 1) IKr blockade increased SD1 more than expected by its dependency on APD; 2) mIKr completely reversed APD and SD1 changes caused by IKr blockade; 3) repolarization was most sensitive to inactivation shifts, which affected APD and SD1 concordantly; 4) activation shifts of the same magnitude had marginal impact on APD but, only when reducing mIKr, they significantly increased SD1; 5) changes in maximal conductance resulted in a pattern similar to that of activation shifts.&lt;/p&gt;

&lt;p&gt;The largest effect on repolarization and its stability are expected from changes in IKr inactivation. APD is less sensitive to changes in other IKr gating parameters, which are better revealed by SD1 changes. SD1 may be more sensitive than APD in detecting IKr-dependent repolarization abnormalities.&lt;/p&gt;
</description>
        <pubDate>Tue, 23 Jun 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//papers/2015/06/23/ikr-impact-on-repolarization-and-its-variability-assessed-by-dynamic-clamp/</link>
        <guid isPermaLink="true">http://rtxi.org//papers/2015/06/23/ikr-impact-on-repolarization-and-its-variability-assessed-by-dynamic-clamp/</guid>
      </item>
    
      <item>
        <title>RTXI 2.0 Released</title>
        <description>&lt;p&gt;We’ve been working hard over the past year to put together the new and improved
Real-Time eXperiment Interface.&lt;/p&gt;

&lt;p&gt;New features:&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;&lt;strong&gt;Improved UI:&lt;/strong&gt; We’ve upgraded the UI framework from Qt3 to Qt4, which
provides RTXI with many built-in performance improvements.&lt;/li&gt;
  &lt;li&gt;&lt;strong&gt;New Linux Base:&lt;/strong&gt; RTXI 2.0 runs on Ubuntu GNOME 14.04 LTS - with it,
you’ll get a stable desktop.&lt;/li&gt;
  &lt;li&gt;&lt;strong&gt;Enhanced Performance:&lt;/strong&gt; For 2.0, we’ve switched from RTAI to Xenomai, a
more versatile real-time kernel, providing a more robust and stable hard
real-time system.&lt;/li&gt;
  &lt;li&gt;&lt;strong&gt;Open Development:&lt;/strong&gt; We’ve migrated the project to GitHub, an excellent
forum for development and all our documentation. Submit an issue; make a
feature request; or watch our repository to stay up-to-date.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Try out v2.0. You can use the &lt;a href=&quot;/install&quot;&gt;live CD&lt;/a&gt; to demo RTXI and later
install it, or you can install a generic Linux distribution of your choice and
use our installation scripts.&lt;/p&gt;

&lt;p&gt;Look through all the documentation on the website to find installation
instructions, notes on hardware configurations, RTXI modules, documentation,
and more. Let us know if you have issues or questions.&lt;/p&gt;
</description>
        <pubDate>Tue, 12 May 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//news/2015/05/12/rtxi-v2-released/</link>
        <guid isPermaLink="true">http://rtxi.org//news/2015/05/12/rtxi-v2-released/</guid>
      </item>
    
      <item>
        <title>Cell-Specific Cardiac Electrophysiology Models</title>
        <description>&lt;p&gt;The traditional cardiac model-building paradigm involves constructing a composite model using data collected from many cells. Equations are derived for each relevant cellular component (e.g., ion channel, exchanger) independently. After the equations for all components are combined to form the composite model, a subset of parameters is tuned, often arbitrarily and by hand, until the model output matches a target objective, such as an action potential. Unfortunately, such models often fail to accurately simulate behavior that is dynamically dissimilar (e.g., arrhythmia) to the simple target objective to which the model was fit. In this study, we develop a new approach in which data are collected via a series of complex electrophysiology protocols from single cardiac myocytes and then used to tune model parameters via a parallel fitting method known as a genetic algorithm (GA). The dynamical complexity of the electrophysiological data, which can only be fit by an automated method such as a GA, leads to more accurately parameterized models that can simulate rich cardiac dynamics. The feasibility of the method is first validated computationally, after which it is used to develop models of isolated guinea pig ventricular myocytes that simulate the electrophysiological dynamics significantly better than does a standard guinea pig model. In addition to improving model fidelity generally, this approach can be used to generate a cell-specific model. By so doing, the approach may be useful in applications ranging from studying the implications of cell-to-cell variability to the prediction of intersubject differences in response to pharmacological treatment.&lt;/p&gt;
</description>
        <pubDate>Thu, 30 Apr 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//papers/2015/04/30/cell-specific-cardiac-electrophysiology-models/</link>
        <guid isPermaLink="true">http://rtxi.org//papers/2015/04/30/cell-specific-cardiac-electrophysiology-models/</guid>
      </item>
    
      <item>
        <title>Repolarization Reserve Evolves Dynamically During the Cardiac Action Potential: Effects of Transient Outward Currents on Early Afterdepolarizations</title>
        <description>&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt; — Transient outward K currents (Ito) have been reported both to
suppress and facilitate early afterdepolarizations (EADs) when repolarization
reserve is reduced. Here we used the dynamic clamp technique to analyze how Ito
accounts for these paradoxical effects on EADs by influencing the dynamic
evolution of repolarization reserve during the action potential.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Methods and Results&lt;/strong&gt; — Isolated patch-clamped rabbit ventricular myocytes
were exposed to either oxidative stress (H2O2) or hypokalemia to induce
bradycardia-dependent EADs at a long pacing cycle length (PCL) of 6 s, when
native rabbit Ito is substantial. EADs disappeared when the PCL was shortened
to 1 s, when Ito becomes negligible due to incomplete recovery from
inactivation. During 6-s PCL, EADs were blocked by the Ito blocker
4-aminopyridine, but reappeared when a virtual current with appropriate
Ito-like properties was reintroduced using the dynamic clamp (n=141 trials).
During 1-s PCL in the absence of 4-aminopyridine, adding a virtual Ito-like
current (n=1,113 trials) caused EADs to reappear over a wide range of Ito
conductance (0.005-0.15 nS/pF), particularly when inactivation kinetics were
slow (τinact≥20 ms) and the pedestal (non-inactivating component) was small
(&amp;lt;25% of peak Ito). Faster inactivation or larger pedestals tended to suppress
EADs.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Conclusions&lt;/strong&gt; — Repolarization reserve evolves dynamically during the cardiac
action potential. Whereas sufficiently large Ito can suppress EADs, a wide
range of intermediate Ito properties can promote EADs by influencing the
temporal evolution of other currents affecting late repolarization reserve.
These findings raise caution in targeting Ito as an antiarrhythmic strategy.&lt;/p&gt;
</description>
        <pubDate>Mon, 20 Apr 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//papers/2015/04/20/repolarization-reserve-evolves-dynamically-during-cardiac-action-potential/</link>
        <guid isPermaLink="true">http://rtxi.org//papers/2015/04/20/repolarization-reserve-evolves-dynamically-during-cardiac-action-potential/</guid>
      </item>
    
      <item>
        <title>List of Resources</title>
        <description>&lt;p&gt;There are a lot of things you need to know to be able to fully use RTXI.
Fortunately, these things aren’t hard to learn, and there is already plenty of
documentation online to help you learn it. This is a non-exhaustive list of
some good resources to learn what you need. They aren’t listed in any specific
order.&lt;/p&gt;

&lt;h4 id=&quot;using-the-command-line&quot;&gt;Using the Command Line&lt;/h4&gt;
&lt;ol&gt;
  &lt;li&gt;&lt;a href=&quot;http://ryanstutorials.net/linuxtutorial/&quot;&gt;http://ryanstutorials.net/linuxtutorial/&lt;/a&gt; (see sections on how to navigate around the filesystem and manipulate files)&lt;/li&gt;
&lt;/ol&gt;

&lt;h4 id=&quot;using-git&quot;&gt;Using Git&lt;/h4&gt;
&lt;ol&gt;
  &lt;li&gt;&lt;a href=&quot;http://git-scm.com/book/en/v2&quot;&gt;http://git-scm.com/book/en/v2&lt;/a&gt;&lt;/li&gt;
  &lt;li&gt;&lt;a href=&quot;http://rogerdudler.github.io/git-guide/&quot;&gt;http://rogerdudler.github.io/git-guide/&lt;/a&gt;&lt;/li&gt;
  &lt;li&gt;&lt;a href=&quot;https://www.atlassian.com/git/tutorials/&quot;&gt;https://www.atlassian.com/git/tutorials/&lt;/a&gt;&lt;/li&gt;
&lt;/ol&gt;

&lt;h4 id=&quot;using-github&quot;&gt;Using GitHub&lt;/h4&gt;
&lt;ol&gt;
  &lt;li&gt;&lt;a href=&quot;https://guides.github.com/&quot;&gt;https://guides.github.com/&lt;/a&gt;&lt;/li&gt;
&lt;/ol&gt;

&lt;h4 id=&quot;learning-programming-and-c&quot;&gt;Learning Programming and C++&lt;/h4&gt;
&lt;ol&gt;
  &lt;li&gt;&lt;a href=&quot;http://www.cplusplus.com/doc/tutorial/&quot;&gt;http://www.cplusplus.com/doc/tutorial/&lt;/a&gt; (prior programming experience helps)&lt;/li&gt;
  &lt;li&gt;&lt;a href=&quot;http://www.penguinprogrammer.co.uk/c-beginners-tutorial/&quot;&gt;http://www.penguinprogrammer.co.uk/c-beginners-tutorial/&lt;/a&gt;&lt;/li&gt;
&lt;/ol&gt;

&lt;h4 id=&quot;qt-and-gui-creation&quot;&gt;Qt and GUI Creation&lt;/h4&gt;
&lt;ol&gt;
  &lt;li&gt;&lt;a href=&quot;http://doc.qt.io/qt-4.8/]&quot;&gt;http://doc.qt.io/qt-4.8/&lt;/a&gt;&lt;br /&gt;
&lt;strong&gt;Note:&lt;/strong&gt; Be careful with some of the Qt tutorials. You don’t need to
instatiate things like QApplication objects, create qmake.pro files, etc.
because RTXI takes care of that. Pay attention to what the UI classes are and
how to use the signal/slot API.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Again, this is a non-exhaustive list of a tiny subset of all that’s available
online and in print. It takes some time to learn these things, just as it does
with anything else. It also wouldn’t hurt to learn these things in general, Qt
excepted. Unix-like environments are very common on clusters for computational
research; Git and GitHub are widely used for coding projects; and C++ very fast
and good to learn, especially given that other languages often use it as a
backend to speed up loops and other heavy sections of code.&lt;/p&gt;
</description>
        <pubDate>Thu, 16 Apr 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//docs/tutorials/2015/04/16/resource-list/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/tutorials/2015/04/16/resource-list/</guid>
      </item>
    
      <item>
        <title>Making New Modules in RTXI</title>
        <description>&lt;p&gt;Outlined here is the development process for making new RTXI modules. For
simplicity, we provide a shell script, called create_template_plugin.sh, for users to
customize without needing to writing everything from scratch. You can access
this script under the scripts folder in RTXI’s root directory. When run, it will create
a source directory with source files and cmake build file in the current directory.&lt;/p&gt;

&lt;h3 id=&quot;to-create-rtxi-modules&quot;&gt;To create RTXI modules:&lt;/h3&gt;

&lt;h4 id=&quot;1-generate-the-rtxi-plugin-project&quot;&gt;1. Generate the RTXI plugin project.&lt;/h4&gt;
&lt;p&gt;Enter or create the directory where you wish to create the plugin, then run the following
command:&lt;/p&gt;

&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;RTXI_SOURCE_LOCATION/scripts/create_template_plugin.sh &lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;

&lt;p&gt;where RTXI_SOURCE_LOCATION is the full directory path to RTXI’s source code. Once you
run the script, the program will ask for a name and a description of your plugin. Afterwards
it will use this information to generate a widgets.hpp, widgets.cpp, and CMakeLists.txt.&lt;/p&gt;

&lt;p&gt;The name of the directory created is the same as the name of the plugin.
An explanation of the header and source files is available in our 
&lt;a href=&quot;http://rtxi.org/docs/manual/#customizing_gui&quot;&gt;user manual&lt;/a&gt;.&lt;/p&gt;

&lt;h4 id=&quot;2-modify-files&quot;&gt;2. Modify files.&lt;/h4&gt;
&lt;p&gt;Modify the RTXI files to run the code you want. The CMakeLists.txt file generated
will automatically search for the RTXI library, but you should modify it if there
are additional dependencies to your plugins. Check CMake and your library’s documentation
on how to find and link the depenency.&lt;/p&gt;

&lt;p&gt;Additionally, it’s good practice to document your code. As a general rule,
document it so that you’re confident that anyone with programming experience
will be able to understand what your code and overall module do.&lt;/p&gt;

&lt;h4 id=&quot;3-configure-compile-and-install&quot;&gt;3. Configure, Compile, and install.&lt;/h4&gt;

&lt;p&gt;Once you’re ready to compile and install your module, go to the base of your
module directory and execute:&lt;/p&gt;

&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;cmake &lt;span class=&quot;nt&quot;&gt;-S&lt;/span&gt; &lt;span class=&quot;nb&quot;&gt;.&lt;/span&gt; &lt;span class=&quot;nt&quot;&gt;-B&lt;/span&gt; build
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;cmake &lt;span class=&quot;nt&quot;&gt;--build&lt;/span&gt; ./build
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;sudo &lt;/span&gt;cmake &lt;span class=&quot;nt&quot;&gt;--install&lt;/span&gt; ./build&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;

</description>
        <pubDate>Fri, 10 Apr 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//docs/tutorials/2015/04/10/making-new-rtxi-modules/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/tutorials/2015/04/10/making-new-rtxi-modules/</guid>
      </item>
    
      <item>
        <title>Posting Bugs and Issues on GitHub</title>
        <description>&lt;p&gt;RTXI is in active development, and our work depends heavily on user feedback.
This tutorial provides instructions for creating bug reports, posting questions
about issues, making feature requests, etc. through GitHub. Though email will
also work, we strongly encourage using GitHub so that users can see existing
issues and contribute to overall discussion. To use GitHub, you will need to
create a &lt;a href=&quot;https://github.com/join&quot;&gt;GitHub account&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; For the sake of absolute clarity, please do not actually create an
issue in the process of going though this tutorial.&lt;/p&gt;

&lt;h4 id=&quot;1-navigate-to-the-repository&quot;&gt;1. Navigate to the repository.&lt;/h4&gt;
&lt;div class=&quot;row&quot;&gt;
  &lt;div class=&quot;col-md-8 col-xs-12&quot;&gt; 
    Go to our GitHub page (
    &lt;a href=&quot;https://github.com/rtxi&quot;&gt;https://github.com/rtxi&lt;/a&gt;). On the page,
    use the search bar or scroll down until you find the software you want to
    report.  If you experience a bug within RTXI and its built-in modules, look
    for the &lt;code&gt;rtxi&lt;/code&gt; repository. If it&apos;s a module you have problems
    with, find the repository that correponds to the module name. Also, if
    you have questions about anything on this website, go to the
    &lt;code&gt;rtxi.github.io&lt;/code&gt; repository.  
    &lt;div&gt;&amp;nbsp;&lt;/div&gt;
  &lt;/div&gt;
  &lt;div class=&quot;col-md-4 col-xs-12&quot;&gt;
    &lt;div class=&quot;row&quot;&gt;
      &lt;div class=&quot;col-xs-10 col-xs-offset-1 col-md-12 col-md-offset-0&quot;&gt;
        &lt;a href=&quot;/assets/img/tutorials/rtxi-github-main-page.png&quot;&gt;
          &lt;img src=&quot;/assets/img/tutorials/rtxi-github-main-page.png&quot; class=&quot;img-responsive&quot; /&gt;
        &lt;/a&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;
&lt;/div&gt;

&lt;h4 id=&quot;2-open-an-issue-on-the-repository-page&quot;&gt;2. Open an issue on the repository page.&lt;/h4&gt;
&lt;p&gt;Each module has an issue page where you can view, submit, and comment on
current development issues. Pictured is the repository page for &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;rtxi&lt;/code&gt;. To
navigate to its issues page, click on &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;Issues&lt;/code&gt; on the right sidebar.&lt;/p&gt;

&lt;p&gt;Click on &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;Issues&lt;/code&gt;. It’s on the sidebar to the right. If you haven’t logged in
to GitHub already, you will be prompted to now. This will open up a new page
that shows all the issues posted to the repository. Look through them to see if
the issue you are having is related to something someone else posted. If it is,
you can add to the existing discussion. If not, then open up a new issue.&lt;/p&gt;

&lt;div class=&quot;row&quot;&gt;
  &lt;div class=&quot;col-xs-12 col-sm-6 col-md-5 col-md-offset-1&quot;&gt;
    &lt;a href=&quot;/assets/img/tutorials/rtxi-github-rtxi-page.png&quot;&gt;
      &lt;img src=&quot;/assets/img/tutorials/rtxi-github-rtxi-page.png&quot; class=&quot;img-responsive&quot; /&gt;
    &lt;/a&gt;
  &lt;/div&gt;
  &lt;div class=&quot;col-sm-6 col-xs-12 col-md-5&quot;&gt;
    &lt;a href=&quot;/assets/img/tutorials/rtxi-github-rtxi-issues.png&quot;&gt;&lt;figure&gt;
      &lt;img src=&quot;/assets/img/tutorials/rtxi-github-rtxi-issues.png&quot; class=&quot;img-responsive&quot; /&gt;
    &lt;/figure&gt;&lt;/a&gt;
  &lt;/div&gt;
&lt;/div&gt;

&lt;h4 id=&quot;3-write-up-your-issue&quot;&gt;3. Write up your issue.&lt;/h4&gt;
&lt;p&gt;Click the appropriate button for whether you’re opening a new issue or joining
an existing thread. Please be as clear and detailed as possible in your
comments, as only posting things like “RTXI is crashing” or “X isn’t working”
doesn’t help us figure out what the issue is.&lt;/p&gt;

&lt;p&gt;For your posts, we ask (but don’t require) you do provide the following
information when appropriate:&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;&lt;strong&gt;The version of RTXI you are using.&lt;/strong&gt;  If you used a live CD to install
RTXI, just say that. If you compiled from source, go to your clone of the
RTXI repository and run &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;git log&lt;/code&gt;. The most recent commit will have a string
associated with it that looks like a random list of letters. Give us the
string.&lt;/li&gt;
  &lt;li&gt;&lt;strong&gt;Error messages from RTXI in the terminal.&lt;/strong&gt; If there are no error
messages, no problem. If RTXI is crashing, it would be incredibly helpful if
you used &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;gdb&lt;/code&gt; to provide a backtrace.&lt;/li&gt;
  &lt;li&gt;&lt;strong&gt;A clear description of the bug.&lt;/strong&gt; Describe the behavior you expect, the
behavior that is happening, and the set of steps that trigger the error.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Clear issue postings are incredibly helpful for us to start debugging your
issues, and it also helps anyone else fully understand the issues you have.&lt;/p&gt;
</description>
        <pubDate>Thu, 09 Apr 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//docs/troubleshoot/2015/04/09/posting-bugs-and-issues/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/troubleshoot/2015/04/09/posting-bugs-and-issues/</guid>
      </item>
    
      <item>
        <title>How to Use Git</title>
        <description>&lt;p&gt;Below are instructions for installing and using Git. Git is a version control
tool that enables users to track revisions and changes in files and coordinate
with collaborators. It is often used for software development.&lt;/p&gt;

&lt;p&gt;Unlike many applications, such as Microsoft Word, editing and saving files
overwrites data. This makes it difficult to track changes without creating
different file names, a process that can get messy very quickly.&lt;/p&gt;

&lt;p&gt;Git takes snapshots of files a user wants to track and maintains a history of
changes that have occurred. This makes backtracking and checking revisions a
simple process, which is especially helpful for large projects with many
developers. It also functions as a collaborative tool by enabling users to make
local copies of a common project and modify them as needed. Users track their
own changes and those of others, and Git incorporates tools that enable
branching and merging of whatever changes people make.&lt;/p&gt;

&lt;p&gt;&lt;a href=&quot;http://www.phdcomics.com/comics/archive/phd101212s.gif&quot;&gt;
  &lt;img src=&quot;http://www.phdcomics.com/comics/archive/phd101212s.gif&quot; class=&quot;img-responsive&quot; style=&quot;max-height:400px;float:right;margin:10px;&quot; /&gt;
&lt;/a&gt;&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; Installing git is not the same as using GitHub. GitHub uses git, but
it is a remote server that users can use as a central location for storing
data. See the instructions for &lt;a href=&quot;https://github.com/join&quot;&gt;opening a GitHub
account&lt;/a&gt;.&lt;/p&gt;

&lt;h4 id=&quot;installing-git-on-linux&quot;&gt;Installing Git on Linux&lt;/h4&gt;

&lt;p&gt;Open the terminal. You can do this from within the Applications menu in GNOME
or by using the &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;CTRL+Alt+t&lt;/code&gt; shortcut. Enter:&lt;/p&gt;

&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;sudo &lt;/span&gt;apt-get &lt;span class=&quot;nb&quot;&gt;install &lt;/span&gt;git&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;

&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; When telling people to enter commands, it is common practice to use
&lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;$&lt;/code&gt; at the start of each line to signify that it is to be entered in the
terminal. Also, &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;#&lt;/code&gt; is used to signify root permissions rather than having
people enter &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;sudo&lt;/code&gt;. In either case, you DO NOT have to enter &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;$&lt;/code&gt; or &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;#&lt;/code&gt; in the
terminal. For example, in the above command. just enter the text &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;sudo apt-get
install git&lt;/code&gt; and hit &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;ENTER&lt;/code&gt;.&lt;/p&gt;

&lt;p&gt;Once Git is installed, configure it with your username and/or email address.
This is preferred in development scenarios so that everyone can identify what
modifications were made by which user. GitHub also maps Git user email
addresses to GitHub accounts. Note that you do not have to give your real name.
Any name will do, as all that is needed is a way to identify who has done what.
Technically, Git does not check email address validity, either, but for
collaborate work, it is best to provide some address so that people can ask
each other questions about changes.&lt;/p&gt;

&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git config &lt;span class=&quot;nt&quot;&gt;--global&lt;/span&gt; user.name &lt;span class=&quot;s1&quot;&gt;&apos;Your name here&apos;&lt;/span&gt;
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git config &lt;span class=&quot;nt&quot;&gt;--global&lt;/span&gt; user.email your@address.here&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;

&lt;p&gt;The &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;git&lt;/code&gt; part of each command specifies that the script that follows contains
Git commands. Git provides a library of functions for executing version
control. Rather than have them directly incorporated into system libraries,
they are made accessible by preceding the command with &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;git&lt;/code&gt;. Therefore, these
commands and all other git commands we will use start with &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;git&lt;/code&gt;.&lt;/p&gt;

&lt;p&gt;The second part, &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;config&lt;/code&gt;, is used to configure information, which is stored in
a hidden file. The tag &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;--global&lt;/code&gt; means that the changes to the user
configuration are to affect all user repositories. The details are saved in a
hidden file called .gitconfig stored at the base of the user’s home directory
(&lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;~/.gitconfig&lt;/code&gt;). Other options allow for different scopes of the effects of
configuration changes. &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;--local&lt;/code&gt; is the default behavior and specifies that
changes be written to hidden file in the working directory called
&lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;.git/config&lt;/code&gt;. You can see what has been set in the config files by running
&lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;git config --list&lt;/code&gt;.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; Should you ever need help with a Git command, you can use `git help&lt;/p&gt;
&lt;commandname&gt;` to check the Git documentation in the terminal. For example, if
unsure about `config`, run `git help config`.  

### Using Local Repositories

#### Initialization 

Git enables users to track local changes and development paths. First, go the
base of your home directory and create some new directories: 


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;cd&lt;/span&gt; ~/
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;mkdir &lt;/span&gt;plugins
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;cd &lt;/span&gt;plugins
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;mkdir &lt;/span&gt;practice
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;cd &lt;/span&gt;practice
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;cd&lt;/span&gt; ..&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


Now, from within the plugins directory, run:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git init&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


&lt;!--
&lt;a href=&quot;/assets/img/tutorials/git-tutorial-1.png&quot;&gt;
  &lt;img src=&quot;/assets/img/tutorials/git-tutorial-1.png&quot; class=&quot;img-responsive&quot;&gt;
&lt;/a&gt;
--&gt;

This command specifies that the directory is to be treated as a Git repository.
By default, Git does not track *any* files. User must enable it in a directory
of their choosing. Once executed, this function creates a hidden directory
called `.git/` that stores information regarding the repository contained in
the directory. 

&lt;!--
&lt;a href=&quot;/assets/img/tutorials/git-tutorial-2.png&quot;&gt;
  &lt;img src=&quot;/assets/img/tutorials/git-tutorial-2.png&quot; class=&quot;img-responsive&quot;&gt;
&lt;/a&gt;
--&gt;

**Note:** Git exists as a version control system. It is not advisable to use it for backing up big files, such as videos, binaries, etc. The entire process gets encumbered quickly. 

#### &lt;a name=&quot;add&quot;&gt;&lt;/a&gt;Adding Files to the Staging Area 

The directory is currently empty, so create some files:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;touch &lt;/span&gt;file1.txt
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;touch &lt;/span&gt;file2.txt
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;touch &lt;/span&gt;file3.txt&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


These files have been added to the repository, or in Git terminology, the
**working tree**. The working tree refers to all of the files that originate
from the base of the directory, which in this case is `~/plugins`. 

By default, Git does not track files that are added to the directory. Users
have to specify that they be tracked. This is done by the `add` command. Git
does, though tell what files are and are not being tracked. Simply use `git
status`


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git add file1.txt file2.txt file3.txt&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


`git add` adds the files to what is called the **staging area**. Basically,
this command generates a snapshot of the files and stores them without adding
them to the permanent version history. In other words, Git is aware of the
files, but it has not added them to the permanent version history. Basically,
git has a 2-stage revision process. The first is to send modified or new files
to the staging area, and the second is to commit them to the permanent version
history. This has its advantages in that it enables users to add files to a
repository as a group that together functions properly. Reverting from one set
of changes to another is simply a process of switching to another snapshot in
the permanent history. This process is explained later. 

To show what files are in the stating area, use:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git status&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


&lt;!--
&lt;a href=&quot;/assets/img/tutorials/git-tutorial-3.png&quot;&gt;
  &lt;img src=&quot;/assets/img/tutorials/git-tutorial-3.png&quot; class=&quot;img-responsive&quot;&gt;
&lt;/a&gt;
--&gt;

If needed, it is possible to unstage files that were added with `git add`. Git
gives the user the command `git rm --cached &lt;filename&gt;`. Try it on one of the
files and see the changes made to the staging area. 


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git &lt;span class=&quot;nb&quot;&gt;rm&lt;/span&gt; &lt;span class=&quot;nt&quot;&gt;--cached&lt;/span&gt; file1.txt
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git status&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


&lt;!--
&lt;a href=&quot;/assets/img/tutorials/git-tutorial-4.png&quot;&gt;
  &lt;img src=&quot;/assets/img/tutorials/git-tutorial-4.png&quot; class=&quot;img-responsive&quot;&gt;
&lt;/a&gt;
--&gt;

The following assumes that all three files are added to the staging area. You
can add all files to the staging area by running `git add -A`. 

#### &lt;a name=&quot;commit&quot;&gt;&lt;/a&gt;Commiting Files 

With the files added to the staging area, the next step is to add them to the
permanent version history. In Git, this process is called a **commit**. Use the
`commit` command. 


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git commit file1.txt file2.txt file3.txt &lt;span class=&quot;nt&quot;&gt;-m&lt;/span&gt; &lt;span class=&quot;s2&quot;&gt;&quot;First commit&quot;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


The `commit` command adds files in the staging area to the repository. Each
commit requires a message that is intended to describe the changes that took
place. This can be done in the command line by using `-m` followed by the
message in quotation marks. If this is omitted, Git defaults to a text editor
where users can type the message. The `commit` command is completed when the
user saves the message and exits the editor.  

If you opt to not specify the filenames for the commit, git will commit all the
files in the staging area.  

Because all the files in the staging area were committed in the last command,
there are all removed from the staging area. You can check with `git status`.  

The version history is in essence a list of commits. To view the complete
history of the project, use:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git log&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


This outputs a list of all the commits, when they were made, the author, the
commit messages, and other information. The string at the top of seemingly
random letters is an encrypted hash of the changes that were made. A hash is a
string that encodes data and is produced by a hash function. Ideally, a hash
function is implemented such that a small change in the data it encodes results
in a large, unpredictable change in the hash. This enables users to check the
file&apos;s integrity and makes it exceedingly difficult to alter the commit
history.  

&lt;!--
&lt;a href=&quot;/assets/img/tutorials/git-tutorial-5.png&quot;&gt;
  &lt;img src=&quot;/assets/img/tutorials/git-tutorial-5.png&quot; class=&quot;img-responsive&quot;&gt;
&lt;/a&gt;
--&gt;

#### &lt;a name=&quot;undo&quot;&gt;&lt;/a&gt;(Optional) Undo a Commit 

If you ever commit something and wish to revert your changes, use the `reset`
command. There are several options. The first is:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git reset &lt;span class=&quot;nt&quot;&gt;--hard&lt;/span&gt; HEAD~1&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


This command erases **everything** that was altered after the previous commit
and sets the working tree to the previous commit. The `--hard` induces the
erasure, and `HEAD~1` moves to the previous commit. `HEAD` is a pointer that
Git uses to point to a specific commit in a branch. `HEAD` by default points to
the latest commit, so to access previous ones, use `~X` where X is the number
of commits ago you want to go. 

Be very careful when using `--hard`. 

The second option:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git reset &lt;span class=&quot;nt&quot;&gt;--mixed&lt;/span&gt; HEAD~1&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


-OR-


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git reset HEAD~1&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


This file preserves the changes made but reverts the HEAD pointer back one
commit. The changes are unstaged, so the working directory matches the previous
commit. 

The last option:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git reset &lt;span class=&quot;nt&quot;&gt;--soft&lt;/span&gt; HEAD~1&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


The only change is that the most recent commit is reversed. The staging area is
the same; it reflects the changes that have been made between the commit to be
erased and its predecessor. This option exactly reverses the effects of a `git
commit` command. 

The following assumes that the commit has not been reversed. All three files
are committed in the repository. 

#### &lt;a name=&quot;branch&quot;&gt;&lt;/a&gt;Branching Repositories 

Now that a commit has been made, branch off and create a new working tree.
Currently, HEAD points to the last commit of the original branch, called
`master`. This is the default name for a new git repository. It is generally
best practice to branch off of master to make changes and then merge changes
back to master once they have been thoroughly audited. That way, whatever code
is in the master branch is guaranteed to work.  

Create a branch called `testing`:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git branch testing&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


This creates a new branch called `testing`. By default, it copies the state
pointed to by HEAD, but it is possible to branch off of previous commits. To
list the available branches, use `git branch`. To switch to the newly created
branch, use:  


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git checkout testing&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


Now, HEAD is pointing to `testing` instead of `master`. Any commits made will
be applied to `testing` as long as it is checked out. 

&lt;!--
&lt;a href=&quot;/assets/img/tutorials/git-tutorial-6.png&quot;&gt;
  &lt;img src=&quot;/assets/img/tutorials/git-tutorial-6.png&quot; class=&quot;img-responsive&quot;&gt;
&lt;/a&gt;
--&gt;

#### &lt;a name=&quot;commitbranch&quot;&gt;&lt;/a&gt;Commiting Branches 

Change the current files. This command will add text to the files saying, &quot;This
is &lt;filename&gt;&quot;. You can use `more &lt;filename&gt;` or `cat &lt;filename&gt;` to output the
contents of a file into the terminal. 


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;find &lt;span class=&quot;nb&quot;&gt;.&lt;/span&gt; &lt;span class=&quot;nt&quot;&gt;-maxdepth&lt;/span&gt; 1 &lt;span class=&quot;nt&quot;&gt;-type&lt;/span&gt; f | xargs &lt;span class=&quot;nt&quot;&gt;-I&lt;/span&gt; &lt;span class=&quot;o&quot;&gt;{}&lt;/span&gt; bash &lt;span class=&quot;nt&quot;&gt;-c&lt;/span&gt; &lt;span class=&quot;s2&quot;&gt;&quot;echo &apos;This is &apos;{} &amp;gt; {}&quot;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


Now that the files have been altered, run `git status` to see what Git has
noticed. Stage the changes and commit them:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git add &lt;span class=&quot;nb&quot;&gt;.&lt;/span&gt;
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git commit &lt;span class=&quot;nb&quot;&gt;.&lt;/span&gt; &lt;span class=&quot;nt&quot;&gt;-m&lt;/span&gt; &lt;span class=&quot;s2&quot;&gt;&quot;First Branch Commit&quot;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


The `.` operator causes commands to affect all files in a directory. Using it
is easier than typing individual file names. 

&lt;!--
&lt;a href=&quot;/assets/img/tutorials/git-tutorial-7.png&quot;&gt;
  &lt;img src=&quot;/assets/img/tutorials/git-tutorial-7.png&quot; class=&quot;img-responsive&quot;&gt;
&lt;/a&gt;
--&gt;

#### &lt;a name=&quot;compare&quot;&gt;&lt;/a&gt;Comparing Branches 

Now that `master` and `testing` differ with one another, switch between them to
see the differences.


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;ls&lt;/span&gt; | xargs &lt;span class=&quot;nb&quot;&gt;cat&lt;/span&gt;
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git checkout master
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;ls&lt;/span&gt; | xargs &lt;span class=&quot;nb&quot;&gt;cat&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


Individually looking through files in different branches can be cumbersome. To
output the differences directly, use the `diff` command. 


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git diff master testing&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


The output should look like:

&lt;!--
&lt;a href=&quot;/assets/img/tutorials/git-tutorial-8.png&quot;&gt;
  &lt;img src=&quot;/assets/img/tutorials/git-tutorial-8.png&quot; class=&quot;img-responsive&quot;&gt;
&lt;/a&gt;
--&gt;

#### &lt;a name=&quot;merge&quot;&gt;&lt;/a&gt;Merging Branches 

Now, merge the changes in `testing` to `master`. Check out the `master` branch
and use the `merge` command.


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git checkout master
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git merge testing&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


You will see an output that summarizes the changes. The `merge` command creates
a new commit that follows the previous version of `master`. 

&lt;!--
&lt;a href=&quot;/assets/img/tutorials/git-tutorial-9.png&quot;&gt;
  &lt;img src=&quot;/assets/img/tutorials/git-tutorial-9.png&quot; class=&quot;img-responsive&quot;&gt;
&lt;/a&gt;
--&gt;

If the merge is successful, there is no need for the `testing` branch. Delete
it. Make sure that the `testing` branch isn&apos;t currently checked out.  


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git branch &lt;span class=&quot;nt&quot;&gt;-d&lt;/span&gt; testing&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


### &lt;a name=&quot;rrepos&quot;&gt;&lt;/a&gt;Using Remote Repositories 

Remote repositories refer to storage locations outside a user&apos;s local
repository. The remote in this example is GitHub, and the repository we&apos;ll be
using is for the &lt;a href=&quot;https://github.com/rtxi/plugin-template&quot;&gt;plugin
template&lt;/a&gt;. If you want to have your own remote repository on GitHub, you
will need to create an account with them and using their website to initialize
the repository. 

#### &lt;a name=&quot;clone&quot;&gt;&lt;/a&gt;Cloning a GitHub Repository  

The format for cloning repositories from GitHub is: 


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git clone https://github.com/&amp;lt;username&amp;gt;/&amp;lt;repository-name&amp;gt;.git&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


To clone from our repositories, the username is `rtxi` and the repositories are
all listed on https://github.com/rtxi. To install the plugin template:  


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;cd&lt;/span&gt; ~/ &lt;span class=&quot;c&quot;&gt;# this line isn&apos;t really needed&lt;/span&gt;
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git clone https://github.com/rtxi/plugin-template.git
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;cd &lt;/span&gt;plugin-template&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


In addition to the files copied from GitHub, Git stores the address of the
remote repository. By default, the name is `origin`. See details on remote
repositories with `git remote -v`. 

#### &lt;a name=&quot;push&quot;&gt;&lt;/a&gt;Pushing to a Remote 

Make some changes to the directory. Add some files, edit them, etc. Then, stage
and commit them. 


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;touch &lt;/span&gt;file1 file2 file3
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git add &lt;span class=&quot;nb&quot;&gt;.&lt;/span&gt;
&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git commit &lt;span class=&quot;nb&quot;&gt;.&lt;/span&gt; &lt;span class=&quot;s2&quot;&gt;&quot;Local commit to push to remote repository&quot;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


**Note:** You will not actually be able to execute the command below
successfully. We don&apos;t allow everyone to push to our repositories. This is what
you&apos;d do, though, if you could. 

Now, send these changes to the remote. The command Git uses for this is `push`. 


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git push https://github.com/&amp;lt;username&amp;gt;/plugin-template.git master &lt;span class=&quot;c&quot;&gt;# will fail&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


Git pushes the changes to the master branch of the remote repository referenced
by the URL. Git also supports aliases for remote URLs. By default, the URL from
which you clone a repository is saved as `origin`. You can view the remotes
tracked by a repository by running `git remote -v`.  

#### &lt;a name=&quot;pull&quot;&gt;&lt;/a&gt;Pulling Changes from a Remote 

Just as one can push changes from a local machine to a remote, it is possible
to &apos;pull&apos; changes back from the remote to the local machine. This comes into
play when modifying the same project on several machines or by several people.
To pull the code and automatically merge the differences, use:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git pull origin&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


If you want to observe the changes but not merge them, use:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git fetch origin&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


This command fetches the changes from the remote repository for the user to
compare with files on the local machine. Once they are determined to be safe
for merging, enter the following from within the directory to which changes are
  to be merged:


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;git merge &amp;lt;fetchedremote&amp;gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


You can use this method to keep your modules and RTXI up to date.  

### &lt;a name=&quot;summary&quot;&gt;&lt;/a&gt;Summary 

The above tutorial is a very basic introduction to Git. Git has many functions,
and many of them overlap in their functionality. As such, there are often many
ways to implement what was described above.  

Should you need more detail, the [Git
documentation](http://git-scm.com/documentation) is an excellent place to
start. Additional help can be found throughout the web:  

 - An [interactive tutorial](http://try.github.io/levels/1/challenges/1) for
   Git syntax.  
 - A [user-made tutorial](http://www.vogella.com/tutorials/Git/article.html)  
 - A detailed site by Atlassian with [tutorials on Git and
   workflow](https://www.atlassian.com/git/)  
&lt;/filename&gt;&lt;/filename&gt;&lt;/filename&gt;&lt;/filename&gt;&lt;/commandname&gt;
</description>
        <pubDate>Tue, 07 Apr 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//docs/tutorials/2015/04/07/how-to-use-git/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/tutorials/2015/04/07/how-to-use-git/</guid>
      </item>
    
      <item>
        <title>Setting a Default Boot Kernel</title>
        <description>&lt;p&gt;It can get annoying choosing the real-time kernel from the submenu every time
you boot your computer, especially if you miss the timing and it boots generic
Linux.&lt;/p&gt;

&lt;p&gt;By default, the GRUB bootloader sorts your installed kernels in descending
version based on the kernel version number, and boots from the first one. You
can save yourself some frustration by changing GRUB to boot from the real-time
kernel by default.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; This is only for convenience. It has no effect on real-time
performance or the functioning of RTXI.&lt;/p&gt;

&lt;p&gt;While it is possible to specify a &lt;em&gt;specific&lt;/em&gt; kernel, it is much easier to tell
GRUB to use the kernel used last time. To make GRUB do this, open
&lt;code&gt;/etc/default/grub&lt;/code&gt; as root and make the following edits:&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;Change &lt;code&gt;GRUB_DEFAULT=0&lt;/code&gt; to &lt;code&gt;GRUB_DEFAULT=saved&lt;/code&gt;.&lt;/li&gt;
  &lt;li&gt;Add a new line that says &lt;code&gt;GRUB_SAVEDEFAULT=true&lt;/code&gt;.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Save your edits (again, you need to be root), and update GRUB by running:&lt;/p&gt;

&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;sudo &lt;/span&gt;update-grub&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;

&lt;p&gt;From now on, GRUB will boot the last-used kernel by default. If you want to
choose a different one, select it manually.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; If you have a LUKS-encrypted volume or otherwise encrypt your boot
partition, this will fail. You will have to manually change the &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;GRUB_DEFAULT&lt;/code&gt;
options to something like &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;&quot;1&amp;gt;2&quot;&lt;/code&gt;, for example, which will make GRUB boot the
kernel listed as the third option in the submenu opened on the second line of
the main menu.&lt;/p&gt;
</description>
        <pubDate>Wed, 01 Apr 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//docs/tutorials/2015/04/01/setting-a-default-boot-kernel/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/tutorials/2015/04/01/setting-a-default-boot-kernel/</guid>
      </item>
    
      <item>
        <title>Why won&apos;t RTXI open?</title>
        <description>&lt;p&gt;There are several reasons for RTXI to not open.&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;&lt;strong&gt;RTXI is already running.&lt;/strong&gt;
    &lt;p&gt;
      If you run &lt;code&gt;rtxi&lt;/code&gt; in the terminal and get this output, RTXI is
      already running:
    &lt;/p&gt;


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;sudo &lt;/span&gt;rtxi
../src/rt_os-xenomai.cpp:123:RT::OS::createTask : failed to create task
../src/rt.cpp:157:RT::System::System : failed to create realtime thread&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


    &lt;p&gt;
      The error happens because only one instance of RTXI can be running on the
      system. Check who is running it by entering:
    &lt;/p&gt; 


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;ps ax &lt;span class=&quot;nt&quot;&gt;-o&lt;/span&gt; euser,comm | &lt;span class=&quot;nb&quot;&gt;grep &lt;/span&gt;rtxi&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


    &lt;p&gt;
      If the command shows someone else&apos;s username, that means they have RTXI
      open. Bug them about closing it or close it yourself by running &lt;code&gt;$
      sudo pkill rtxi&lt;/code&gt;. Note that workspaces, open files, etc. will
      &lt;strong&gt;not&lt;/strong&gt; be saved when force-closing RTXI. 
    &lt;/p&gt;
    &lt;p&gt;
      If it&apos;s your username, RTXI may not have exited cleanly from sometime
      earlier. You can run &lt;code&gt;$ sudo pkill rtxi&lt;/code&gt; for this case, too.
    &lt;/p&gt;
    &lt;p&gt;
      Now, you should be able to run RTXI.
    &lt;/p&gt;
  &lt;/li&gt;
  &lt;li&gt;&lt;strong&gt;You aren&apos;t using a real-time kernel.&lt;/strong&gt;

    &lt;p&gt;Check the kernel you are using. Run this in the terminal:&lt;/p&gt;


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;uname&lt;/span&gt; &lt;span class=&quot;nt&quot;&gt;-r&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


    &lt;p&gt;
      You will get one line of output that tells you what kernel you are using.
      If it has the word &quot;xenomai&quot; in it, then it&apos;s a real-time kernel. If not,
      then it isn&apos;t.
    &lt;/p&gt; 
    &lt;p&gt;
      If it&apos;s not a real-time kernel, you&apos;ll have to reboot your computer and
      pick a real-time kernel in the GRUB boot menu that pops up. If you don&apos;t
      see it, enter the &quot;Advanced options...&quot; submenu and look there.
    &lt;/p&gt;
    &lt;p&gt;
      Also, see 
      &lt;a href=&quot;/docs/tutorials/2015/04/01/setting-a-default-boot-kernel/&quot;&gt;this
      page &lt;/a&gt; about setting a default kernel.
    &lt;/p&gt;
  &lt;/li&gt;
&lt;/ol&gt;
</description>
        <pubDate>Wed, 01 Apr 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//docs/faqs/2015/04/01/rtxi-doesn't-open/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/faqs/2015/04/01/rtxi-doesn't-open/</guid>
      </item>
    
      <item>
        <title>RTXI 2015 Deadline Approaching</title>
        <description>&lt;p&gt;The deadline for registering for the RTXI 2015 conference is fast approacing.
Register now to book your position here. Noteworthy dates:&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Registration:&lt;/strong&gt; April 30&lt;br /&gt;
&lt;strong&gt;Hotel:&lt;/strong&gt; April 15&lt;/p&gt;

&lt;p&gt;The conference is May 7-8 at the Georgia Academy of Medicine. Registration is
$75 for students and $125 for everyone else. Fee waivers are liberally
available upon request.&lt;/p&gt;
</description>
        <pubDate>Fri, 27 Mar 2015 00:00:00 -0400</pubDate>
        <link>http://rtxi.org//news/2015/03/27/rtxi-2015-registration-deadline-approaching/</link>
        <guid isPermaLink="true">http://rtxi.org//news/2015/03/27/rtxi-2015-registration-deadline-approaching/</guid>
      </item>
    
      <item>
        <title>Linux Freezes after Reboot</title>
        <description>&lt;p&gt;If you do an OS-based reboot of your the computer and your log-in screen is
laggy or displays errors, it’s probably because &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;kexec-tools&lt;/code&gt; are handling
reboots.  When compiling an RT kernel, you were prompted whether or not to let
&lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;kexec-tools&lt;/code&gt; handle reboots. 
You are advised in the installation instructions (and here) to not allow that.&lt;/p&gt;

&lt;p&gt;The &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;kexec-tools&lt;/code&gt; utility normally is used to perform ‘warm reboots,’ which is
when the computer reloads a kernel without fully shutting the system down.  (In
contrast, a cold reboot is when you fully shut down the computer, meaning that
the machine fully stops and it begins to cool down.) The lag you experience is
probably because kexec-tools is rebooting to a non-RT kernel.  Your system is
at that point should not be relied on for running real-time applications.&lt;/p&gt;

&lt;p&gt;To temporarily fix this, fully shutdown the computer to do a cold reboot. To
permanently fix it, disable kexec-tools from handling reboots:&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;Open /etc/default/kexec (as root).&lt;/li&gt;
  &lt;li&gt;Change &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;LOAD_KEXEC&lt;/code&gt; from &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;true&lt;/code&gt; to &lt;code class=&quot;language-plaintext highlighter-rouge&quot;&gt;false&lt;/code&gt;&lt;/li&gt;
  &lt;li&gt;Save and exit.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Now, kexec-tools will no longer handle reboots, and your system reboot as one
would expect.&lt;/p&gt;
</description>
        <pubDate>Mon, 02 Mar 2015 00:00:00 -0500</pubDate>
        <link>http://rtxi.org//docs/troubleshoot/2015/03/02/linux-frozen-after-reboot/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/troubleshoot/2015/03/02/linux-frozen-after-reboot/</guid>
      </item>
    
      <item>
        <title>Using Graphics Cards</title>
        <description>&lt;p&gt;Choosing graphics cards can be a thorny issue in standard Linux alone, let
alone real-time Linux. Often, open-source drivers lag behind proprietary ones
in terms of compatibility with newer hardware and displays. The two main types,
AMD and Nvidia, are supported for the most part within Linux.&lt;/p&gt;

&lt;p&gt;For RTXI, we strongly encourage you to use the open-source drivers. Nouveau is
the open-source one for Nvidia cards, and radeon is for AMD ones. No
configuration or input on your part is needed to use them. When you install
Linux and boot, your kernel will detect the graphics hardware and load the
corresponding driver. You can check to see if your driver is loaded by running:&lt;/p&gt;

&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;lsmod | &lt;span class=&quot;nb&quot;&gt;grep&lt;/span&gt; &lt;span class=&quot;s2&quot;&gt;&quot;radeon&lt;/span&gt;&lt;span class=&quot;se&quot;&gt;\|&lt;/span&gt;&lt;span class=&quot;s2&quot;&gt;nouveau&quot;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;

&lt;p&gt;The reason we use open-source drivers is that they use the kernel to directly
leverage the graphics card to compute things like the UI and desktop.
Proprietary drivers, while technically doing the same thing, function
differently and can degrade real-time performance by causing latencies to spike
to as high as 100us on some machines. Skipping the drivers altogether forces
the CPU to compute the UI, which when coupled with the RT kernel, will make the
UI slow and laggy and the real-time performance poorer.&lt;/p&gt;

&lt;p&gt;Here are some guidelines for using graphics cards:&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;Newer cards are less likely to be supported by open-source drivers.&lt;/li&gt;
  &lt;li&gt;AMD provides better support for its &lt;strong&gt;open-source&lt;/strong&gt; radeon driver than
Nvidia does for nouveau.&lt;/li&gt;
  &lt;li&gt;Nvidia’s &lt;strong&gt;proprietary driver&lt;/strong&gt; performs better than AMD’s proprietary
driver (fglrx) and generally provides better support for newer hardware.&lt;/li&gt;
  &lt;li&gt;If you have an AMD card, use it. If you have an Nvidia one, try it. Tell us
if you have issues. We want to keep track of what works and what doesn’t.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Lastly, if you have issues with your display looking weird or distorted, it’s
probably your graphics card. Check our graphics troubleshooting page for
suggestions on what to do or browse though forums online. Someone’s probably
had the same issue as you at some point.&lt;/p&gt;
</description>
        <pubDate>Mon, 23 Feb 2015 00:00:00 -0500</pubDate>
        <link>http://rtxi.org//docs/tutorials/2015/02/23/using-graphics-cards/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/tutorials/2015/02/23/using-graphics-cards/</guid>
      </item>
    
      <item>
        <title>My System Is Frozen or Slow!</title>
        <description>&lt;p&gt;This issue can be caused by many tings, and getting to its specific cause will
require patience. Here are some things to look for:&lt;/p&gt;

&lt;ol&gt;
  &lt;li&gt;When does the system freeze or slow down?
    &lt;ul&gt;
      &lt;li&gt;Does it freeze after you pick a kernel in the GRUB menu?&lt;/li&gt;
      &lt;li&gt;Does RTXI cause the slowdown or is it slow upon boot?&lt;/li&gt;
      &lt;li&gt;Does the freeze affect all kernels? Or is it just the real-time one(s)?&lt;/li&gt;
    &lt;/ul&gt;
  &lt;/li&gt;
  &lt;li&gt;What graphics card are you using?
    &lt;ul&gt;
      &lt;li&gt;Is it Nvidia or AMD?&lt;/li&gt;
      &lt;li&gt;Are you using open-source or proprietary drivers?&lt;/li&gt;
    &lt;/ul&gt;
  &lt;/li&gt;
  &lt;li&gt;
    &lt;p&gt;If running an RT kernel, are the DAQ drivers loaded? Open the Control Panel
module in RTXI and see if the “analogy0” channel is open. If not, the
drivers aren’t detecting your DAQ.&lt;/p&gt;
  &lt;/li&gt;
  &lt;li&gt;How is your BIOS configured? Some settings, such as multithreading,
frequency scaling, and spread-spectrum clocking, degrade real-time
performance and should be disabled.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;&lt;br /&gt;&lt;/p&gt;

&lt;p&gt;These types of issues can have several causes. It can be your graphics card not
being fully supported by the driver, the DAQ driver interfering with
framebuffers, interrupt line collisions, etc. If you have issues, you are
encouraged to contact us for help. Here are some tips and fixes for common
problems:&lt;/p&gt;

&lt;p&gt;&lt;br /&gt;&lt;/p&gt;

&lt;dl class=&quot;dl-horizontal&quot;&gt;
  &lt;dt&gt;Freezing at Boot&lt;/dt&gt;
    &lt;dd&gt;
      &lt;p&gt;
        If your system freezes when it boots, it couls be caused by interrupt
        collisions between the graphics driver and the analogy driver. We&apos;ve
        noticied this happening most frequently on machines with Nvidia cards.
        You can fix this by opening up the computer and moving the graphics
        card to a different PCI slot.  
      &lt;/p&gt;
      &lt;p&gt;
        If that doesn&apos;t fix your system, you can delve deeper to find out
        whether there are still interrupt collisions. When Linux freezes, you
        can drop to another tty by entering &lt;code&gt;Ctrl+Alt+F2&lt;/code&gt;. You can
        then enter you login information. From the new shell, enter:  
      &lt;/p&gt;


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;lspci &lt;span class=&quot;nt&quot;&gt;-v&lt;/span&gt; | less&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


      &lt;p&gt;
        Scroll through the output and check if anything has the same IRQ number
        as the DAQ (the National Instuments card) or the graphics card.
        Occasionally, things like the Ethernet card or a USB port can
        interfere.  If you don&apos;t have a spare port, you&apos;ll need to get a new
        graphics card.  We recommend AMD cards that have been released long
        enough for Ubuntu to fully support them.  A list of compatible cards is
        available 
        &lt;a href=&quot;https://help.ubuntu.com/community/RadeonDriver&quot;&gt; on Ubuntu&apos;s
        site.&lt;/a&gt; 
      &lt;/p&gt;
    &lt;/dd&gt;
  &lt;br /&gt;
  &lt;dt&gt;Poor Performance&lt;/dt&gt;
    &lt;dd&gt;
      &lt;p&gt;
        If your system has consistently poor performance, visible within the
        Performance Measurement Module, that worsens when the DAQ channels are
        opened, it is likely because the graphics drivers are not using kernel
        modesetting properly. What that means is that the CPU is handling
        things the graphics card should, causing it to interfere with the
        real-time processes it needs to devote time to doing.  
      &lt;/p&gt;
      &lt;p&gt;
        This is likely caused by the graphics card being not fully supported by
        open-source drivers. You may need to replace your driver. To see if
        your system is using the graphics driver, run:  
      &lt;/p&gt;


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;&lt;span class=&quot;nb&quot;&gt;sudo &lt;/span&gt;lshw &lt;span class=&quot;nt&quot;&gt;-C&lt;/span&gt; display | &lt;span class=&quot;nb&quot;&gt;grep &lt;/span&gt;configuration&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


      &lt;p&gt;
        If you don&apos;t see your graphics driver (radeon or nouveau) listed, then
        it&apos;s not being properly used. You can also check this by looking at the
        &lt;code&gt;dmesg&lt;/code&gt; output:
      &lt;/p&gt;


&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;nv&quot;&gt;$ &lt;/span&gt;dmesg | &lt;span class=&quot;nb&quot;&gt;grep&lt;/span&gt; &lt;span class=&quot;s2&quot;&gt;&quot;radeon&lt;/span&gt;&lt;span class=&quot;se&quot;&gt;\|&lt;/span&gt;&lt;span class=&quot;s2&quot;&gt;nouveau&quot;&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;


      &lt;p&gt;
        If the driver is working properly, you&apos;ll see a lot of output. If not,
        you probably won&apos;t see anything. 
      &lt;/p&gt;
      &lt;p&gt;
        Let us know if you need help with this issue. Sending us the output
        from the above commands will help immensely in figuring out your
        problem.  
      &lt;/p&gt;
    &lt;/dd&gt;
&lt;/dl&gt;

&lt;p&gt;Hardware can be idiosyncratic and interfere with real-time, but lucky for you,
we’re here to help.&lt;/p&gt;
</description>
        <pubDate>Mon, 23 Feb 2015 00:00:00 -0500</pubDate>
        <link>http://rtxi.org//docs/troubleshoot/2015/02/23/system-frozen-or-slow/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/troubleshoot/2015/02/23/system-frozen-or-slow/</guid>
      </item>
    
      <item>
        <title>RTXI 2015 Registration Open!</title>
        <description>&lt;p&gt;Just reminding everyone that registration for RTXI 2015 is now open! Check out
our &lt;a href=&quot;/conference/&quot;&gt;conference page&lt;/a&gt; to learn about our upcoming conference.
Registration is open until April 1st at 5:00 PM Eastern Time.&lt;/p&gt;
</description>
        <pubDate>Wed, 21 Jan 2015 00:00:00 -0500</pubDate>
        <link>http://rtxi.org//news/2015/01/21/rtxi-2015-registration-is-open/</link>
        <guid isPermaLink="true">http://rtxi.org//news/2015/01/21/rtxi-2015-registration-is-open/</guid>
      </item>
    
      <item>
        <title>Why are there negative latencies?</title>
        <description>&lt;p&gt;Negative latencies mean that the latency test has not been properly calibrated.
The test calculates latencies based on when tasks are expected to be completed,
with some overhead going toward computing the timer. To avoid including the
time it takes to compute the timer, xenomai offsets the measured latency with a
static value, written in nanoseconds and stored in
&lt;code&gt;/proc/xenomai/latency&lt;/code&gt;. If the value is negative, then xenomai is
overcompensating.&lt;/p&gt;

&lt;p&gt;You can correct this behavior by running (as root):&lt;/p&gt;

&lt;figure class=&quot;highlight&quot;&gt;&lt;pre&gt;&lt;code class=&quot;language-bash&quot; data-lang=&quot;bash&quot;&gt;&lt;span class=&quot;c&quot;&gt;# echo 0 &amp;gt; /proc/xenomai/latency&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;&lt;/figure&gt;

&lt;p&gt;What this means is that the latency test will not try to factor out the time to
compute the timer.&lt;/p&gt;
</description>
        <pubDate>Tue, 20 Jan 2015 00:00:00 -0500</pubDate>
        <link>http://rtxi.org//docs/faqs/2015/01/20/why-are-there-negative-latencies/</link>
        <guid isPermaLink="true">http://rtxi.org//docs/faqs/2015/01/20/why-are-there-negative-latencies/</guid>
      </item>
    
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