I have started looking at the SAGA strawman document and wanted to comment on the section "The URL problem". URL -> URI ---------- In many circumstances URI has replaced URL, see for example Web Arch (http://www.w3.org/TR/webarch/). URIs allow you to identify things for which there may not yet exist a representation - for example an output file for job that has not started or http://host.net/tmp/file in the SAGA document. Comparing URIs -------------- Rules for comparing URIs are scheme dependent, so you cannot compare a ftp URI to http URI, see http://www.textuality.com/tag/uri-comp-4 and http://www.faqs.org/rfcs/rfc2396.html. The SAGA document effectively says this but I am not sure there is any need to go beyond saying you cannot compare URIs from different schemes. Two URIs with different schemes can identify the same resource, ie they are aliases, but you cannot tell this from comparing the URIs. However redirection may be used to relate the URIs. For example a HTTP redirect: a user may get a 3XX response when attempting to retrieve a representation of resource using HTTP which points him to a FTP server. So there is a question of how SAGA would handle a redirection - redirection of POST or PUT in HTTP requires user input. any scheme ---------- The W3C recommends not inventing schemes, section 2.4 of Web Arch. cheers Mark