1. A method comprising: identifying at least one virtual disk used by a virtual machine, wherein the virtual machine facilitates concurrent implementation of multiple operating systems on a single computer, the at least one virtual disk comprises a file system used by the virtual machine, and the file system comprises a file system structure and a file; identifying a volume implemented on the at least one virtual disk, wherein the identifying the volume is performed by examining a master boot record to identify partitions of the at least one virtual disk to identify volume boundaries, and identifying a volume format used by the volume; accessing the file system structure; generating a map for the volume, based upon the file system structure, wherein the map identifies a location of the file on a physical disk, in which the file is stored, the map comprises a conversion of an extent information of the file on the virtual disk to a location of the file on the physical disk, the file is comprised in a backup image of the at least one virtual disk, the map allows access to the file in the backup image, while the backup image is in an unmounted state, the map allows restoration of the file directly from the backup image without mounting the backup image, and the backup image is a point-in-time copy of the at least one virtual disk; and transmitting the map and the backup image to a backup storage device, wherein the backup storage device comprises the physical disk, the map and the backup image are stored on the backup storage device, the generating and the transmitting are performed by a computing device, and the computing device implements the virtual machine.