Application service providing (ASP) achieves this goal, but it has become common only in the world of business administration, accounting, and customer management. ASP also frees a company or academic institution from having to buy and maintain the hardware and software necessary for the applications being used: The required resources are provided by the ASP provider and are charged per use. In the world of scientific computing, technical simulations, and visualization of scientific data, however, the concept of ASP has not yet seen widespread use.
ASPIC attempts to fill this gap. It provides an easy to use interface to the computational powers of high performance PC clusters. The user can start and control batch simulations and browse his data on the server via an ordinary web browser, the complex technology underneath, such as queueing systems etc. is hidden away from the user.
ASPIC not only provides a portal for using commercial software. It can also be used for sharing a code developed by an academic institution, both with cooperating research groups or with the scientific world at large.
In order to provide security from intruders and protect sensitive data, all data tranfers are being encrypted. Both sides authenticate via x509 certificates. The ASPIC system includes a certificate agency to issue client certificates. The servers authenticate via server certificates from well known certification agencies.
Two and more ASPIC servers can be operated as a simple compute grid. When the user configures a job to be run on this ASPIC grid, the job is automatically being transferred to a compute host with sufficient resources. After the simulation the result data is transferred to the user's home server. File browsing and job control via the web interface is transparent throughout this grid as is the accounting of resource usage for later billing in a commercial environment.
To integrate simulations into complete complex workflows, the ASPIC servers can be operated via XMLRPC over SSL from external applications in a secure manner. An example implementation is the integration of ASPIC into the flowGuide workflow management software from science+computing ag. Here the ASPIC system acts as a simple grid technology, in which simulation jobs are being transferred to cumpute servers which provide the requested resources. A typical scenario is preprocessing on the machine of the user, number crunching on an ASPIC server, retransfer of data to the user's machine with subsequent postprocessing there.
To reduce the amount of unnecessary data transfer, work is being done to visualize simulation results directly on the ASPIC server and only to stream image data to the user's machine.
We will specifically present two sample applications, one of a commercial code for the simulation of electrical fields in automobiles (FEKO), one of a Smoothed Particle Hydrodynamics code developed by the University of Tübingen. Visualization of the resulting data as part of the ASPIC installation is also shown.
