controls user access and schedules jobs to workers. It provides a web
interface for managing jobs and users, and a set of web
services. These are user service and worker/warehouse services
-implemented using WSDL \cite{WebServ2002}.
+implemented using WSDL (Web Service Description Language) \cite{WebServ2002}, that simplifies
+client development for languages that support it (and most popular programming languages do).
A worker is a Java daemon that runs on the user machine. Assumed to be
volatile, the workers report periodically themselves to the
\label{xwch}
\begin{centering}
\includegraphics [scale=0.2]{figures/xwcharchitecture.pdf}
- \caption{The XWCH Architecture}
+ \caption{The XtremWeb-CH architecture}
\end{centering}
\end{figure}
A warehouse is a file server that acts as a data storage system for
workers and client programs. Workers may not necessarily be able to
-communicate directly with each other, due to firewalls and NAT
+communicate directly with each others, due to firewalls and NAT
sub-networks. For these reasons, warehouses are used as intermediaries
to exchange, store and retrieve data.
Job submission is done by a client program which is written using a
flexible API, available for Java and C/C++ programs. The client
program runs on a “client node” and calls the user services to submit
-jobs (Figure \ref{xwch}, (1)). The main flexibility provided by the use of this
+jobs (Figure \ref{xwch}, (1)). The main flexibility provided by the use of this
architecture is to control and generate dynamically jobs especially
when their number cannot be known in advance. Communications between
the coordinator and the workers are always initiated by the workers
-following a pull model (Figure \ref{xwch}, (2)):
+following a pull model (Figure \ref{xwch}, (2)):
\begin{itemize}
-\item Workers receive jobs (Figure \ref{xwch}, (3)) only if they send a “work
+\item Workers receive jobs (Figure \ref{xwch}, (3)) only if they send a “work
request” signal;
\item When a worker finishes its job, it stores its output file on
- warehouse and sends a “work result” signal to the coordinator;
+ a warehouse and sends a “work result” signal to the coordinator;
\item During its execution, a worker (respectively warehouse)
- periodically sends “work alive” to the worker services (respectively
- warehouse services) to report itself to the coordinator.
+ periodically sends “work alive” to the worker service (respectively
+ warehouse service) to report itself to the coordinator.
\end{itemize}
As a whole, XWCH is easy to install, maintain and use. Its components
