next up previous
Next: Verifying Clock Algorithms Up: Figures in the book Previous: Model of a Computation

Logical Clocks

Figure: An illustration of a clock assignment that sets $C(u) = C(v)$.
\begin{figure}\centerline{\epsfbox{figs/2clock.eps}}\end{figure}

Figure: A logical clock algorithm
\fbox{\begin{minipage}{\textwidth}\sf
\begin{tabbing}
x\=xxxx\=xxxx\=xxxx\=xxxx\...
...l event $(s,internal,t)$:\\
\> \> $t.c := s.c + 1;$\end{tabbing}\end{minipage}}

Figure: A vector clock algorithm
\fbox{\begin{minipage}{\textwidth}\sf
\begin{tabbing}
x\=xxxx\=xxxx\=xxxx\=xxxx\...
...\> $t.v := s.v;$\\
\> \>$t.v[j] := t.v[j] + 1;$\\
\end{tabbing}\end{minipage}}

Figure: A sample execution of the vector clock algorithm
\begin{figure}\begin{center}
\hspace*{-0.6in}
\centerline{\epsfbox{figs/VectorAlgoFig.eps}}\end{center}\end{figure}



Vijay K. Garg 2005-02-08