Patent ID: 8589913

Claim:
A method of installing, by a processor, a block-level write tracking driver which tracks writes to a volume in an operating system, the method comprising: the write tracking driver: receiving a request to operate in a promiscuous mode; finding a block device stack corresponding to the volume; selecting a device object in the block device stack; accessing a driver object pointed to by the device object; comparing the driver name in the driver object to a name of a VolSnap driver; if the driver name is the same as the name of the VolSnap driver, replacing a function pointer entry in a dispatch table in the driver object; and if the driver name is not the same as the name of the VolSnap driver, do not replace the function pointer entry in the dispatch table in the driver object; wherein, in the promiscuous mode, when comparing the driver name, if a write request is being processed by the VolSnap driver and the volume is not recognized, marking a range of blocks as being modified that corresponds to the write request in all volumes being write tracked.