Update for ikiwiki page placement.

[ert_linux_web.git] / index.html

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@@ -70,6 +70,35 @@ for this driver can be found
 on <a href="http://rtime.felk.cvut.cz/hw/index.php/Humusoft_MF6xx">DCE
 HW Wiki page</a>.</p>
 
+<h2 id="platformselect">RT-Capable Platform and Kernel</h2>
+<p>
+Standard distribution Linux kernel does not guarantee bounded latencies for many operations.
+The use of <a href="http://rt.wiki.kernel.org/">real-time variant</a> of <a href="http://en.wikipedia.org/wiki/Linux">Linux</a>
+kernel is required to make system durable. This kernel variants minimizes regions
+where switch to the highest priority (i.e. Linux ERT generated) task is blocked by
+kernel when servicing system calls for other tasks.
+</p>
+<p>
+Selection of the right version of the kernel is not enough for non-disruptive
+operation. Computer system hardware selection is critical as well. The system
+has to provide enough computational power for compiled in blocks data evaluation
+evaluation and Linux kernel services processing. Other critical disturbance sources
+are hardware caused latencies and lags in a program processing by CPU. The source
+can be bus systems load by other subsystems (i.e. graphic processor memory access,
+peripheral DMA - SSD, SD-card, Flash controller etc.). The other critical source of
+latencies in x86 based systems is <a href="http://en.wikipedia.org/wiki/System_Management_Mode">SMI</a>
+processing. The SMI enable and processing is under BIOS and motherboard vendor control
+and this problem cannot be resolved by operating system. This means that proper
+hardware selection is critical.
+</p>
+<p>
+A long period evaluation data of different combinations of Linux kernel version
+runing on many CPU architectures and boards from many vendors is <a href="http://www.osadl.org/">OSADL</a>
+<a href="http://www.osadl.org/Quality-assurance-at-the-OSADL-QA-Farm.osadl-services-qa.0.html">Quality Assurance Farm</a>.
+According to these track records carefully selected x86 or embedded GNU/Linux system can run
+real-time tasks with sampling frequencies up to 20&nbsp;kHz with no losing sample per months.
+</p>
+
 <h2 id="download">Source Code and Download</h2>
 
 <dl>
@@ -109,12 +138,24 @@ fly-by-wire system load. Simulink CANopen blockset integrates a
 processing support to the generated code and enables the user to develop distributed embedded
 control applications with CANopen communication.</p>
 
-<p><img width=600 src="LinTarget.JPG" alt="Original code generation workflow"></p>
-
-<p><img width=600 src="CANopenExample.JPG" alt="Model including node controlled over CANopen"></p>
+[[!img LinTarget.JPG size=300x alt="Original code generation workflow"]]
+[[!img CANopenExample.JPG size=300x alt="Model including node controlled over CANopen"]]
 
 <p>Lukáš Hamáček, “<b>RTW target for Linux with CANopen support</b>”, Master Thesis, Prague 2009. (<a href="dp_2009_hamacek_lukas.pdf">Pdf</a>)</p>
 
+<h2 id="applications">Systems Controlled Linux Target for Embedded Coder</h2>
+
+Some more information about concrete examples of controlled systems/setups:
+
+<dl>
+  <dt><b>Moving Slide</b> parallel kinematic/robot control</dt>
+    <dd>The Linux ERT target is used at Adaptive Systems Department (Academy of Sciences
+      of Czech Republic, UTIA institute) to realize control system for parallel kinematics
+      control research projects. See <a href="moving-slide/index.html">respective page for more
+      information about project</a>.
+    </dd>
+</ul>
+
 <h2 id="contributors">Project Contributors</h2>
 
 <dl>