Continuous data protection over intermittent connections, such as continuous data backup for laptops or wireless devices

A computer-implemented method for tracking modifications made to data objects stored on a portable device, the method comprising:

• determining when the portable device is connected to a data target, wherein the portable device stores data objects, and wherein the data target is configured to store copies of data objects from the portable device;
• and
• when it is determined that the portable device is not connected to the data target, at the portable device:
• receiving an indication of a modification made to a data object stored on the portable device;
• determining information associated with the modification made to the data object;
• and
• storing the associated information in a data structure, wherein the data structure is configured to enable retrieval of the associated information from the data structure and to enable determination of the modification made to the data object based on the associated information:
• wherein the portable device includes a file system and a continuous data protection filter configured to monitor modifications to the file system, and further wherein receiving an indication of a modification includes:
• monitoring a modification to a data object on the file system, wherein the monitoring is performed by the continuous data protection filter;
• and
• storing an indication of the modification monitored by the continuous data protection filter.

A computer-readable storage medium encoded with instructions for controlling a computer system to replicate changes from a portable computing system to a data storage system, by a method comprising:

• receiving a data structure storing information identifying portions of data objects stored on a portable computing system to which modifications were made;
• retrieving the information from the data structure;
• based on the retrieved information, determining the portions of data objects to which modifications were made;
• and
• for each determined portion of a data object, copying the modification made to the portion of the data object from the portable computing system to the data storage system;
• wherein the portable computing system includes a data store having blocks, wherein the information identifying portions of data objects includes information identifying modified blocks, and
• further wherein:
• determining the portions of data objects to which modifications were made includes determining modified blocks, offsets within the modified blocks at which the modifications begin, and lengths of modified data within the modified blocks;
• and
• for each determined portion of a data object, copying the modification includes copying only the data within the modified block at the determined offset and length of modified data from the portable computing system to the data storage system.