Patent ID: 8086567

Claim:
A storage apparatus, comprising: storage means for storing data; committing means for making a commitment of an availability of a certain storage space of the storage means to a source device, wherein the storage apparatus and the source device are within a group of devices in a trust environment, wherein each group member device is bound by its respective commitment to the group of devices, wherein the commitments of the group member devices can be different from each other as long as each commitment reaches a registration rule of the group of devices, wherein the registration rule comprises (a) a predetermined minimum storage capacity sharing with other group member devices, (b) an undisturbance of a file originated from the source device stored in the certain storage space, and (c) a predetermined minimum requirement of number of hours per day of online accessibility of the certain storage space; detecting means for detecting the availability of the certain storage space of the storage means to produce a detection result (i) by itself or (ii) in response to an inquiry received from the source device, wherein the detection result includes an indication that (a) a file from the source device stored by the storage apparatus is still there, (b) the stored file is undisturbed, and (c) an online accessibility exceeds the minimum requirement; and communication means for informing the source device of the detection result, wherein responsive to a detection result indicating that the commitment is violated, the source device takes corresponding action(s) to delete, and thereby cause loss of data of, a file(s) originated from the storage apparatus and stored outside the storage apparatus within the group of devices.