Continuous data backup

A computer-implemented method of restoring data to a storage device, comprising:

• accessing a journal having a plurality of entries, wherein each of the entries points to prior data that existed on the storage device before a write caused the entry to be created, wherein an entry in the journal is created for each data write to the storage device that occurred after an initial time, wherein the prior data corresponding to each of the plurality of entries in the journal is maintained in the storage device after each new data write after the initial time, wherein each entry pointing to prior data provides a previous state corresponding to the prior data, wherein the previous state is accessible after writing the new data, and wherein the new data and subsequent new data are kept from overwriting the prior data corresponding to each entry;
• and
• using at least one of the entries to remap the storage device to point to the prior data, wherein using at least one of the entries to remap the storage device includes changing a map of a switch coupled to the storage device.

A computer-implemented journal used for continuous backup of a storage device, comprising:

• a first entry that points to a first storage location containing old data replaced by new data written to the storage device;
• and
• a plurality of additional entries that point to respective additional storage locations containing old data replaced by new data written to the storage device, wherein for every write to the storage device that occurs after an initial time, there is a corresponding entry, and wherein the old data corresponding to each of the plurality of additional entries is maintained in the storage device after each new write to the storage device after the initial time, wherein each of the entries pointing to the storage locations containing the old data provides a previous state corresponding to the old data, wherein the previous state is accessible after writing the new data, and wherein the new data and subsequent new data are kept from overwriting the old data corresponding to each of the entries, wherein at least one of the entries remaps the storage device by changing a map of a switch coupled to the storage device.