\documentclass{article}
\input{6824-preamble}

\begin{document}
\psetnum{15}
\date{2005/04/26}

\begin{pset}
  Two-phase commit is necessary because servers with persistent data
  commit their changes to disk. In a one-phase commit system, if this
  fails, or if some server crashes while preparing, the transaction
  coordinator will not be able to notify the other servers to abort,
  and an inconsistent state will occur. This is not a problem for
  volatile data, since it is lost anyway if the server crashes.
\end{pset}

\end{document}