1. Grid Computing
AEI Numerical Relativity Group has access to high-end resources in over ten centers in Europe/USA
They want:
Bigger simulations, more simulations and faster throughput
Intuitive IO at local workstation
No new systems/techniques to master!!
How to make best use of these resources?
Provide easier access … noone can remember ten usernames, passwords, batch systems, file systems, … great start!!!
Combine resources for larger productions runs (more resolution badly needed!)
Dynamic scenarios … automatically use what is available
Many other reasons for Grid Computing for computer scientists, funding agencies, supercomputer centers ...

2. Grand Picture Viz of data from previous simulations in SF café
Remote Viz in St Louis
Remote steering and monitoring from airport
Remote Viz and steering from Berlin
DataGrid/DPSS
Downsampling
IsoSurfaces
http
HDF5
T3E: Garching
Origin: NCSA
Globus
Simulations launched from Cactus Portal
Grid enabled Cactus runs on distributed machines

3. Thorn HTTPD
Thorn which allows simulation any to act as its own web server
Connect to simulation from any browser anywhere
Monitor run: parameters, basic visualization, ...
Change steerable parameters
See running example at
Wireless remote viz, monitoring and steering

4. Users View

5. User Portal Find resources Authentification Launch simulation
automatically finds machines with a user allocation (group aware!)
continuously monitor resources, network etc.
Authentification
single login, don’t need to remember lots of usernames/passwords
Launch simulation
automatically create executable on chosen machine
write data to appropriate storage location
negotiate local queue structures
Monitor/steer simulations
access remote visualization and steering while simulation is running
collaborative … choose who else can look in and/or steer
performance … how efficient is the simulation?
Archiving
store thorn lists, parameter files, output locations, configurations, …

6. Cactus Portal KDI ASC Project
Technology: Globus, GSI, Java Beans, DHTML, Java CoG, MyProxy, GPDK, TomCat, Stronghold
Allows submission of distributed runs
Accesses the ASC Grid Testbed (SDSC, NCSA, Argonne, ZIB, AHPCC, WashU, AEI)
Undergoing testing by users now!
Main difficulty now is that it requires everything to work …
But is going to revolutionise our use of computing resources

7. ASC: Astrophysics Simulation Collaboratory
NSF Funded Knowledge and Distributed Intelligence project
Institutes: WashU, Rutgers, Argonne, U. Chicago, NCSA
Aim: Develop a collaboratory for the astrophysics community to provide the capability for massively parallel computation including AMR, interactive visualization and metacomputing.
ASC Portal: General simulation portal interfacing to Cactus
Globus, GSI, Java Beans, DHTML, Java CoG, MyProxy, GPDK, TomCat, Stronghold
Version 1 included code assembly, compilation, job submission
Version 2 now being developed, based on user feedback