diff --git a/figures/Atos-logo-880x660.png b/figures/Atos-logo-880x660.png
new file mode 100644
index 0000000000000000000000000000000000000000..749b882b824d1e47f9b07a0b40b51f07e746f935
Binary files /dev/null and b/figures/Atos-logo-880x660.png differ
diff --git a/figures/atos-logo.png b/figures/atos-logo.png
new file mode 100644
index 0000000000000000000000000000000000000000..395abdce9b65535c2d3a08a89cf32f3aa588d111
Binary files /dev/null and b/figures/atos-logo.png differ
diff --git a/slides.pdf b/slides.pdf
index 2d07d4bb9aec089a2aa2db48beea062be838b15c..94dc9faa18e9375f390b9106492d510f42bc1e9b 100644
Binary files a/slides.pdf and b/slides.pdf differ
diff --git a/slides.tex b/slides.tex
index 52de98bda738e20634d1c39cab45d085bc71d66f..f018ec769d6f3aa4926c3659a2aeef6a97806f38 100644
--- a/slides.tex
+++ b/slides.tex
@@ -14,7 +14,7 @@
 \usepackage{array,booktabs}
 \usepackage{pgfpages}
 \usepackage{listings}
-\setbeameroption{show notes on second screen=right}
+%\setbeameroption{show notes on second screen=right}
 \lstset{language=Bash}
 
 \definecolor{identifiercolor}{rgb}{0,0,0}
@@ -74,13 +74,14 @@
 \date{Rennes 2019, \today}
 \author{
   \underline{Adrien Faure}, Millian Poquet\\
-  \vspace{1cm}
- % \includegraphics[height=1cm]{figures/logo-inp.png}
-  \hspace{0.1cm}
+  \vspace{0.9cm}
+ % \includegraphics[height=1cm]{figureslogo-inp.png}
   \includegraphics[height=1cm]{figures/logo-inria.jpg}
+  \hspace{0.3cm}
+  \includegraphics[height=1cm]{./figures/atos-logo.png}
  % \hspace{0.1cm}
  % \includegraphics[height=1cm]{figures/logo-cnrs}
-  \hspace{0.1cm}
+  \hspace{0.4cm}
   \includegraphics[height=1cm]{./figures/logo-lig.jpg}
  % \hspace{0.1cm}
  % \includegraphics[height=1cm]{figures/logo-uga
@@ -213,6 +214,7 @@ The running environment should be explicit:
     \end{tcolorbox}
 
     Satellites:
+    \only<1>{
 
     \begin{tcolorbox}[colframe=black,colback=gray!10,coltext=black]
       NixOS - The Purely Functional Linux Distribution
@@ -225,8 +227,23 @@ The running environment should be explicit:
     \begin{tcolorbox}[colframe=black,colback=gray!10,coltext=black]
       NixOps - The NixOS Deployment Tool (2011)
     \end{tcolorbox}
+  }
+    \only<2>{
+    \begin{tcolorbox}[colframe=gray!50,colback=gray!1,coltext=gray!100]
+      NixOS - The Purely Functional Linux Distribution
+    \end{tcolorbox}
+
+    \begin{tcolorbox}[colframe=gray!50,colback=gray!1,coltext=gray!100]
+      Hydra - Nix-based continuous build system (2008)
+    \end{tcolorbox}
+
+    \begin{tcolorbox}[colframe=gray!50,colback=gray!1,coltext=gray!100]
+      NixOps - The NixOS Deployment Tool (2011)
+    \end{tcolorbox}
+  }
   \end{frame}
 
+
   \subsection{Expression Language}
 
   \begin{frame}{}
@@ -275,65 +292,67 @@ The running environment should be explicit:
     \end{itemize}
   \end{frame}
 
-\begin{frame}{}
-  All \emph{official} packages are defined into the repository:
-  \begin{tcolorbox}[colframe=black,colback=gray!10,coltext=black]{Nixpkgs - \textcolor{red}{\url{https://github.com/NixOS/nixpkgs}}}
-  \end{tcolorbox}
-    \begin{columns}
-      \begin{column}{0.5\textwidth}
-        \begin{itemize}
-          \item First commit:  Mar 2003
-          \item \textbf{$>$22 000} packages
-          \item \textbf{$>$2 100} contributors
-        \end{itemize}
-      \end{column}
-      \begin{column}{0.5\textwidth}
-        \begin{itemize}
-          \item \textbf{$>$183 600} commits
-        \end{itemize}
-      \end{column}
-    \end{columns}
-\end{frame}
-
-\section{How Does it Work ?}
+% \begin{frame}{}
+%   All \emph{official} packages are defined into the repository:
+%   \begin{tcolorbox}[colframe=black,colback=gray!10,coltext=black]{Nixpkgs - \textcolor{red}{\url{https://github.com/NixOS/nixpkgs}}}
+%   \end{tcolorbox}
+%     \begin{columns}
+%       \begin{column}{0.5\textwidth}
+%         \begin{itemize}
+%           \item First commit:  Mar 2003
+%           \item \textbf{$>$22 000} packages
+%           \item \textbf{$>$2 100} contributors
+%         \end{itemize}
+%       \end{column}
+%       \begin{column}{0.5\textwidth}
+%         \begin{itemize}
+%           \item \textbf{$>$183 600} commits
+%         \end{itemize}
+%       \end{column}
+%     \end{columns}
+% \end{frame}
+
+\section{Nix Structure}
+
+\begin{frame}{Main Concept}
+
+  % Nix borrows its concept from Functional Languages. \\
+    \begin{tcolorbox}[colframe=black,colback=gray!10,coltext=black]
+  Nix applies the concept of functional programming languages to packages management.
+    \end{tcolorbox}
+  \vspace{1em}
 
-\begin{frame}
+  Each software building action is described through functions.
+  \note{Function into the Functional paradigm point of view}
 
-  How does it works / How can we use it ?
+  \vspace{1em}
+  Packages dependencies are also functions given as inputs.
 
 \end{frame}
 
 \begin{frame}[fragile]{Derivations}
-  \begin{onlyenv}<1>
-    \note{https://nixos.org/nixos/nix-pills/our-first-derivation.html\\}
-    Nix refers to \textbf{derivation} instead of package. \\
-
-    \vspace{1em}
-    From the Nix point of view, a derivation is a build action, \\
-    described by a Nix set.
+ \note{https://nixos.org/nixos/nix-pills/our-first-derivation.html\\}
+     % Nix refers to \textbf{derivation} instead of package. \\
+  % A package is a defined by a \textbf{derivation}. \\
 
-    \vspace{1em}
-    Once built, a  derivation is located into a common place\\
-    the \textbf{Nix store}.
-
-    \vspace{1em}
-
-    A derivation is identified with a unique hash as follows:
-
-  \begin{lstlisting}[language=Nix,basicstyle=\small]
-        /nix/store/hash-name
-  \end{lstlisting}
+  % It can be build with the command \textit{nix-build}.
+  \begin{tcolorbox}[colframe=black,colback=gray!10,coltext=black]
+    A derivation is a Nix build action.
+  \end{tcolorbox}
+  \begin{onlyenv}<2>
 
-    \note{A derivation is a set of attributes describing a building process \\}
+  \vspace{1em}
+  It is an attribute set describing how to build a package.
 
   \end{onlyenv}
+  \pause
 
-  \begin{onlyenv}<2>
-  %\begin{adjustbox}{width=\textwidth,height=\textheight,keepaspectratio}
   \vspace{-1em}
 
+  \begin{onlyenv}<3>
+
   \begin{lstlisting}[language=Nix,basicstyle=\small]
-{
+stdenv.mkDerivation {
   name = "chord";
 
   src = fetchurl {
@@ -341,24 +360,25 @@ The running environment should be explicit:
     sha256 = "1h2jgq5pspyiskffq777nhi5rf0y8h...";
   };
 
-  builder = "build.sh";
   buildInputs = [ simgrid boost cmake ];
 
   meta = ..;
 }
+\end{lstlisting}
 
-  \end{lstlisting}
-   \end{onlyenv}
-\end{frame}
+\end{onlyenv}
 
+\end{frame}
 
 \begin{frame}[fragile]{Store}
 
-  All build derivations are stored in the nix store: \texttt{/nix/store}.\\
+\begin{tcolorbox}[colframe=black,colback=gray!10,coltext=black]
+Nix uses a single directory to store every packages.
+\end{tcolorbox}
 
   \vspace{1em}
 
-  They are identified with a sha-256 hash of the source nix file and
+  A packagesr is identified with a sha-256 hash of the source nix file and
   its "inputs".
 
   \begin{lstlisting}[basicstyle=\small]
@@ -376,6 +396,24 @@ The running environment should be explicit:
 
 \end{frame}
 
+\begin{frame}[plain]{Nixpkgs}
+
+\begin{tcolorbox}[colframe=black,colback=gray!10,coltext=black]
+  \center
+  NixPkgs is an open source git repository.
+\end{tcolorbox}
+
+  \only<1>{
+    \vspace{1em}
+    It contains the derivations of all application (and libraries) \emph{officialy} available with Nix.
+  }
+  \only<1>{
+    \vspace{1em}
+    Packages are distributed as Nix expression (the so called derivations).
+  }
+
+\end{frame}
+
 \begin{frame}[plain]{Channels}
 
   \only<1>{