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UNIX example figures.

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Daniel Hillerström 5 years ago
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  1. 1
      macros.tex
  2. 92
      thesis.tex

1
macros.tex

@ -333,6 +333,7 @@
\newcommand{\conf}{\mathcal{C}}
% UNIX example
\newcommand{\UNIX}{UNIX}
\newcommand{\OSname}[0]{Tiny UNIX}
\newcommand{\exit}{\dec{exit}}
\newcommand{\Exit}{\dec{Exit}}

92
thesis.tex

@ -54,7 +54,7 @@
\usepackage{tikz}
\usetikzlibrary{fit,calc,trees,positioning,arrows,chains,shapes.geometric,%
decorations.pathreplacing,decorations.pathmorphing,shapes,%
matrix,shapes.symbols,intersections}
matrix,shapes.symbols,intersections,tikzmark}
\usepackage[customcolors,shade]{hf-tikz} % Shaded backgrounds.
\hfsetfillcolor{gray!40}
@ -2011,18 +2011,18 @@ and demonstrate how we can use the power of (deep) effect handlers to
implement a tiny operating system that supports multiple users,
time-sharing, and file i/o.
%
The operating system will be a variation of UNIX~\cite{RitchieT74},
The operating system will be a variation of \UNIX{}~\cite{RitchieT74},
which we will call \OSname{}.
%
To make the task tractable we will occasionally jump some hops and
make some simplifying assumptions, nevertheless the resulting
implementation will capture the essence of a UNIX-like operating
implementation will capture the essence of a \UNIX{}-like operating
system.
%
The implementation will be composed of several small modular effect
handlers, that each handles a particular set of system commands. In
this respect, we will truly realise \OSname{} in the spirit of the
UNIX philosophy~\cite[Section~1.6]{Raymond03}. The implementation of
\UNIX{} philosophy~\cite[Section~1.6]{Raymond03}. The implementation of
the operating system will showcase several computational effects in
action including \emph{dynamic binding}, \emph{nondeterminism}, and
\emph{state}.
@ -2030,22 +2030,22 @@ action including \emph{dynamic binding}, \emph{nondeterminism}, and
\subsection{Basic i/o}
\label{sec:tiny-unix-bio}
The file system is a cornerstone of UNIX as the notion of \emph{file}
in UNIX provides a unified abstraction for storing text, interprocess
The file system is a cornerstone of \UNIX{} as the notion of \emph{file}
in \UNIX{} provides a unified abstraction for storing text, interprocess
communication, and access to devices such as terminals, printers,
network, etc.
%
Initially, we shall take a rather basic view of the file system. In
fact, our initial system will only contain a single file, and
moreover, the system will only support writing operations. This system
hardly qualifies as a UNIX file system. Nevertheless, it serves a
hardly qualifies as a \UNIX{} file system. Nevertheless, it serves a
crucial role for development of \OSname{}, because it provides the
only means for us to be able to observe the effects of processes.
%
We defer development of a more advanced file system to
Section~\ref{sec:tiny-unix-io}.
Much like UNIX we shall model a file as a list of characters, that is
Much like \UNIX{} we shall model a file as a list of characters, that is
$\UFile \defas \List~\Char$. For convenience we will use the same
model for strings, $\String \defas \List~\Char$, such that we can use
string literal notation to denote the $\strlit{contents of a file}$.
@ -2164,7 +2164,7 @@ We can now write some contents to the file and observe the effects.
\subsection{Dynamic binding: user-specific environments}
\label{sec:tiny-unix-env}
In UNIX an environment maps keys to string-values. A key-value pair is
In \UNIX{} an environment maps keys to string-values. A key-value pair is
referred to as an \emph{environment variable}. Each user gets their
own environment with their own set of environment variables. Some
environment variable names are common to all environments, but their
@ -2245,7 +2245,7 @@ an arbitrary number of variables. This can be done by parameterising
the $\Ask$ operation by some name representation (e.g. a string),
which the environment handler can use to index into a list of string
values. In case the name is unbound the environment handler can
embrace UNIX's laissez-faire attitude and resume with the empty
embrace \UNIX{}'s laissez-faire attitude and resume with the empty
string.
\paragraph{Session management}
@ -2369,6 +2369,59 @@ string.
\subsection{State: file i/o}
\label{sec:tiny-unix-io}
\begin{figure}
\centering
\begin{tabular}[t]{| l |}
\hline
\multicolumn{1}{| c |}{\textbf{Directory}} \\
\hline
\strlit{hamlet}\tikzmark{hamlet}\\
\hline
\strlit{ritchie.txt}\\
\hline
\multicolumn{1}{| c |}{$\cdots$}\\
\hline
\strlit{act3}\\
\hline
\multicolumn{1}{| c |}{$\cdots$}\\
\hline
\strlit{stdout}\\
\hline
\end{tabular}
\hspace{1.5cm}
\begin{tabular}[t]{| c |}
\hline
\multicolumn{1}{| c |}{\textbf{I-List}} \\
\hline
2\\
\hline
1\tikzmark{hamletino}\\
\hline
\multicolumn{1}{| c |}{$\cdots$}\\
\hline
1\\
\hline
\end{tabular}
\hspace{1.5cm}
\begin{tabular}[t]{| l |}
\hline
\multicolumn{1}{| c |}{\textbf{Data region}} \\
\hline
\strlit{UNIX is basically...}\\
\hline
\tikzmark{hamletdr}\strlit{To be, or not to be...}\\
\hline
\multicolumn{1}{| c |}{$\cdots$}\\
\hline
\strlit{}\\
\hline
\end{tabular}
\tikz[remember picture,overlay]\draw[->,thick] ([xshift=1.3cm,yshift=0.1cm]pic cs:hamlet) -- ([xshift=-0.85cm,yshift=0.1cm]pic cs:hamletino) node[] {};
\tikz[remember picture,overlay]\draw[->,thick] ([xshift=0.62cm,yshift=0.1cm]pic cs:hamletino) -- ([xshift=-0.23cm,yshift=0.1cm]pic cs:hamletdr) node[] {};
\caption{\UNIX{} directory, i-list, and data region mappings}\label{fig:unix-mappings}
\end{figure}
\[
\State~\alpha \defas \{\Get:\UnitType \opto \alpha;\Put:\alpha \opto \UnitType\}
\]
@ -2402,6 +2455,25 @@ string.
\el
\]
\begin{figure}
\centering
\begin{tikzpicture}[node distance=4cm,auto,>=stealth']
\node[] (server) {\bfseries Bob (server)};
\node[left = of server] (client) {\bfseries Alice (client)};
\node[below of=server, node distance=5cm] (server_ground) {};
\node[below of=client, node distance=5cm] (client_ground) {};
%
\draw (client) -- (client_ground);
\draw (server) -- (server_ground);
\draw[->] ($(client)!0.25!(client_ground)$) -- node[rotate=-6,above,scale=0.7,midway]{SYN 42} ($(server)!0.40!(server_ground)$);
\draw[<-] ($(client)!0.56!(client_ground)$) -- node[rotate=6,above,scale=0.7,midway]{SYN 84;ACK 43} ($(server)!0.41!(server_ground)$);
\draw[->] ($(client)!0.57!(client_ground)$) -- node[rotate=-6,above,scale=0.7,midway]{ACK 44} ($(server)!0.72!(server_ground)$);
\end{tikzpicture}
\caption{Sequence diagram for the TCP handshake example.}\label{fig:tcp-handshake}
\end{figure}
\paragraph{TCP threeway handshake}
% The existing literature already contain an extensive amount of
% introductory examples of programming with (deep) effect
% handlers~\cite{KammarLO13,Pretnar15,Leijen17}.

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