--- a/mercurial.tex
+++ b/mercurial.tex
@@ -58,4 +58,294 @@
   \tableofcontents
 \end{frame}
 
+\section{Introduction}
+
+\subsection{Basic Concepts}
+
+\begin{frame}{What do we want from a version control system?}
+  Very basic features:
+  \begin{itemize}
+  \item let you save changes
+  \item browser the history
+  \end{itemize}
+
+  \pause
+  Basic features:
+  \begin{itemize}
+  \item collaboration
+  \item branches
+  \item tags
+  \end{itemize}
+
+  \pause
+  Nice features:
+  \begin{itemize}
+  \item speed!
+  \item much more, as you will see\dots
+  \end{itemize}
+\end{frame}
+
+\begin{frame}{Branches}
+  A central concept:
+  \begin{itemize}
+  \item parallel lines of development
+  \item used to track releases
+  \item used to isolate disruptive changes
+  \end{itemize}
+
+  \begin{tikzpicture}
+    \path[use as bounding box] (0, -1.5) rectangle (10, 1.5);
+
+    \tikzstyle{branch}=[blue!60, ->, >=latex, line join=round]
+    \tikzstyle{tag}=[draw=yellow!50!orange, fill=yellow!50]
+
+    \draw<2->[->] (0, -1) -- +(10, 0) node[below left] {time};
+
+    \draw<5>[branch, blue!30, line width=2mm]
+      (v10) -- ++(1,1)
+            -- coordinate[pos=0.4] (v101) ++(3,0);
+
+    \draw<6->[branch, blue!30, line width=2mm]
+      (v10) -- ++(1,1)
+            -- coordinate[pos=0.2] (v101)
+               coordinate[pos=0.7] (v102) ++(6,0);
+
+    \draw<2-3>[branch, line width=3mm]
+      (0,0) -- coordinate[pos=0.4] (v10) +(2.5,0);
+
+    \draw<4-6>[branch, line width=3mm]
+      (0,0) -- coordinate[pos=0.2] (v10) +(5,0);
+
+    \draw<3-> (v10) ++(0, 0.3) -- ++(0, -0.6) node[below, tag] {1.0};
+    \draw<5-> (v101) ++(0, 0.2) -- +(0, -0.4) node[below, tag] {1.0.1};
+    \draw<6-> (v102) ++(0, 0.2) -- +(0, -0.4) node[below, tag] {1.0.2};
+  \end{tikzpicture}
+\end{frame}
+
+\begin{frame}{Merging}
+  The oposite of branching:
+  \begin{itemize}
+  \item combines two branches
+  \item used to merge back bugfixes
+  \item used to integrate feature branches
+  \end{itemize}
+
+  \begin{tikzpicture}
+    \path[use as bounding box] (0, -1.5) rectangle (10, 1.5);
+
+    \tikzstyle{branch}=[blue!60, ->, >=latex, line join=round]
+    \tikzstyle{tag}=[draw=yellow!50!orange, fill=yellow!50]
+
+    \draw[->] (0, -1) -- +(10, 0) node[below left] {time};
+
+    \draw<1-2>[branch, blue!30, line width=2mm]
+      (v10) -- ++(1,1)
+            -- coordinate[pos=0.2] (v101)
+               coordinate[pos=0.7] (v102) ++(6,0);
+
+    \draw<3->[branch, blue!30, line width=2mm]
+      (v10) -- ++(1,1)
+            -- coordinate[pos=0.2] (v101)
+               coordinate[pos=0.7] (v102) ++(6,0)
+            -- +(1, -1);
+
+    \draw<2->[branch, blue!30, line width=2mm]
+      (v101) ++(0.8, 0) -- +(1,-1);
+
+    \draw<1>[branch, line width=3mm]
+      (0,0) -- coordinate[pos=0.2] (v10) +(5,0);
+
+    \draw<2>[branch, line width=3mm]
+      (0,0) -- coordinate[pos=0.125] (v10) +(8,0);
+
+    \draw<3>[branch, line width=3mm]
+      (0,0) -- coordinate[pos=0.1] (v10) +(10,0);
+
+    \draw<1-> (v10) ++(0, 0.3) -- ++(0, -0.6) node[below, tag] {1.0};
+    \draw<1-> (v101) ++(0, 0.2) -- +(0, -0.4) node[below, tag] {1.0.1};
+    \draw<1-> (v102) ++(0, 0.2) -- +(0, -0.4) node[below, tag] {1.0.2};
+  \end{tikzpicture}
+\end{frame}
+
+
+
+\subsection{Historic Context}
+
+\begin{frame}{Revision Control System (RCS)}
+  Version control from the 1980s:
+  \begin{itemize}
+  \item store changes (date, commit message)
+  \item browse history
+  \end{itemize}
+
+  \bigskip
+
+  \begin{tikzpicture}
+    \begin{scope}[start chain]
+      \node<2->[on chain,left] at (0, 0.5) {hello.c};
+      \node<3->[on chain,xshift=-8mm, rev] {};
+      \node<4->[on chain,join,rev] {};
+      \node<5->[on chain,join,rev] {};
+    \end{scope}
+    \begin{scope}[start chain]
+      \node<2->[on chain,left] at (0, 0) {Makefile};
+      \node<3->[on chain,xshift=-8mm,rev] {};
+      \node<6->[on chain,join,rev] {};
+    \end{scope}
+  \end{tikzpicture}
+\end{frame}
+
+\begin{frame}{Concurrent Versions System (CVS)}
+  Version control in the 1990s:
+  \begin{itemize}
+  \item collaboration over the network
+  \item several working copies
+  \item one central repository
+  \end{itemize}
+
+  \pause
+
+  \begin{center}
+  \begin{tikzpicture}
+    \begin{scope}[start chain, node distance=16mm]
+      \node[working copy, on chain, label=above:Alice] (Alice)
+           {hello.c\\ Makefile};
+      \node[repository, on chain, label=above:CVS Server] (repository) {};
+      \node[working copy, on chain, label=above:Bob] (Bob)
+           {hello.c\\ Makefile};
+    \end{scope}
+
+    \begin{scope}[scale=0.5,transform shape]
+      \begin{scope}[start chain]
+        \node[on chain,left, yshift=3mm, xshift=-2mm] at (repository)
+             {hello.c};
+        \node[on chain,xshift=-8mm,rev] {};
+        \node[on chain,join,rev] {};
+      \end{scope}
+      \begin{scope}[start chain]
+        \node[on chain,left, yshift=-3mm, xshift=-2mm] at (repository)
+             {Makefile};
+        \node[on chain,xshift=-8mm,rev] {};
+        \node<3->[on chain,join,rev] {};
+      \end{scope}
+    \end{scope}
+
+    \draw<3>[->] (Alice) -- node[above] {commit} (repository);
+    \draw<4>[->] (repository) -- node[above] {update} (Bob);
+  \end{tikzpicture}
+  \end{center}
+\end{frame}
+
+\begin{frame}{So, everything is good?}
+  CVS has many limitations:
+  \begin{itemize}
+  \item no atomic commits
+  \item no rename information
+  \item branches? I hope you have a CVS guru at hand\dots
+  \end{itemize}
+\end{frame}
+
+\begin{frame}{Subversion (SVN)}
+  Version control from this millennia --- ``\emph{CVS done right}'':
+  \begin{itemize}
+  \item atomic commits
+  \item tracks renames
+  \item supports some operations without network access
+  \end{itemize}
+\end{frame}
+
+\begin{frame}{Branches in SVN}
+  Subversion knows nothing about branches!
+  \begin{itemize}
+  \item but SVN has a cheap copy mechanism
+  \item used for tags and branches
+  \end{itemize}
+
+  \begin{tikzpicture}
+    \node<2->[working copy, below, text width=20mm, label=above:r10]
+             (a) at (0, 0) {
+      trunk/\\
+      \quad hello.c\\
+      \quad Makefile\\
+      branches/
+    };
+    \node<3->[working copy, below, text width=25mm, label=above:r11]
+             (b) at (3.5, 0) {
+      trunk/\\
+      \quad hello.c\\
+      \quad Makefile\\
+      branches/\\
+      \quad goodbye/\\
+      \qquad hello.c\\
+      \qquad Makefile\\
+    };
+    \node<4->[working copy, below, text width=30mm, label=above:r12]
+             (c) at (7.5, 0) {
+      trunk/\\
+      \quad hello.c\\
+      \quad Makefile\\
+      branches/\\
+      \quad goodbye/\\
+      \qquad hello.c\\
+      \qquad goodbye.c\\
+      \qquad Makefile\\
+    };
+
+    \tikzstyle{s}=[yshift=-5mm]
+    \tikzstyle{every pin edge}=[draw, red, <-]
+
+    \draw<3->[->] ([s] a.north east) -- ([s] b.north west);
+    \draw<4->[->] ([s] b.north east) -- ([s] c.north west);
+  \end{tikzpicture}
+\end{frame}
+
+\begin{frame}{Merging Branches in SVN}
+  Branches are only interesting if you can merge them:
+  \begin{itemize}
+  \item before SVN 1.5: no built-in support for merging(!)
+  \item SVN 1.5 and later: tracks info needed for merging
+  \end{itemize}
+
+  \pause
+
+  \begin{center}
+  \begin{tikzpicture}
+    \node[draw=structure, fill=structure!20!white, text justified,
+      text width=0.9\textwidth, font=\small] {The bottom line is that
+      Subversion's merge-tracking feature has an \alert{extremely
+        complex} internal implementation, and the
+      \texttt{svn:mergeinfo} property is the only window the user has
+      into the machinery. Because the feature is \alert{relatively
+        new}, a numbers of edge cases and possible unexpected
+      behaviors may pop up. \hfill\itshape ---Version Control with
+      Subversion};
+  \end{tikzpicture}
+  \end{center}
+
+  (Mercurial has robust built-in support for merging branches.)
+\end{frame}
+
+
+%% \begin{frame}{Basic Version Control}
+%%   Working alone:
+%%   \begin{itemize}
+%%   \item store changes (date, commit message)
+%%   \item browse history
+%%   \end{itemize}
+%%   (RCS did this in the 1980s)
+%% \end{frame}
+%%
+%% \begin{frame}{Working with Others}
+%%   Distributing changes:
+%%   \begin{itemize}
+%%   \item get new changes from a server
+%%   \item send new commits to a server
+%%   \item \emph{resolve} conflicts between you and server
+%%   \end{itemize}
+%%   (CVS did this in 1990s)
+%% \end{frame}
+
+
 \end{document}
+
+% LocalWords:  SVN Makefile