Locians, Following up on some thoughts of using XML to describe the GUI of the viewers (which is in some ways an older idea), I came across James Henstridge's GLADE-XML GUI generators. If you don't know what GLADE is, it's a GTK GUI builder, sort of like Delphi but without the editor. It actually uses XML as a file format for saving projects, so the XML describes GUI's. James has a Python module, which is actually part of PyGTK. You may want to look at it: http://bioinformatics.org/loci/pyglade-0.5.12.tar.gz He also has a C library to generate GUI's at runtime from a binary: ftp://ftp.daa.com.au/pub/james/gnome/libglade-0.0.3.tar.gz Either one could be useful to us. A viewer's controls I imagine can be specified this way. But note that this is a change from the idea of downloading a Python GUIscript to call GUImegawidgets. (The GUImegawidgets may still be used in some cases though.) Actually, if we make it so that Loci doesn't need to download various viewers, our need for something like RPM becomes less certain. Maybe we can use a simple database. Does anyone know of a simple GPL database in Python? Another use of XML (yes, another one), would be to describe vector graphics (drawn by GILT?). Does anyone know of an existing XML to describe vector graphics? Jeff -- J.W. Bizzaro mailto:bizzaro at bc.edu Boston College Chemistry http://www.uml.edu/Dept/Chem/Bizzaro/ --