asr or Apple Software Restore is a command line utility in Mac OS X used to apply a DMG disk image to a selected partition or mount point on a file system. It is often used for cloning large numbers of Macintosh computers. Apple Software Restore can read an image locally or from a server via HTTP or its own multicast asr:// URI.asr has two methods it can use to restore an image to a volume: it can either copy items in a file-by-file mode, or it can directly block-copy the image.