Dear All: I am sending this draft document in case it is relevant to the OGSA-WG and/or BES discussions. In this document, I use a simple example (a skeleton execution service) to compare and contrast four approaches to representing state, namely WSRF, WS-Transfer, REST, and "state id." I haven't sent this earlier because I'd hoped to integrate numerous comments that I've received from Savas and others. I hope to do so in the next week or two, but perhaps this draft is still of interest. Regards -- Ian. _______________________________________________________________ Ian Foster www.mcs.anl.gov/~foster Math & Computer Science Div. Dept of Computer Science Argonne National Laboratory The University of Chicago Argonne, IL 60439, U.S.A. Chicago, IL 60637, U.S.A. Tel: 630 252 4619 Fax: 630 252 1997 Globus Alliance, www.globus.org