I have read the Qcow image format in http://www.gnome.org/~markmc/qcow-image-format-version-1.html<http://www.gnome.org/%7Emarkmc/qcow-image-format-version-1.html> but I am so confusing about the backing_file.I Know if you wanna read sth,first check the qcow file,if not exist,then find in the origin file.but how to connect the origin file(base image)from the qcow image! I have read the source tools/ioemu/block-qcow.c ,but i still find how to implement it. can someone tell me the implement of the qcow format and how it works? thanks! _______________________________________________ Xen-community mailing list Xen-community@lists.xensource.com http://lists.xensource.com/mailman/listinfo/xen-community