SRM
An SRM URL has the form srm://dmx.lbl.gov:6253//srm/DRM/srmv1?SFN=/tmp/try1 and the file URL looks like file:////tmp/aaa.
srm://dmx.lbl.gov:6253//srm/DRM/srmv1?SFN=/tmp/try1
file:////tmp/aaa