Patent ID: 7058771

Claim:
A system for managing data units stored in a hard disk storage device, the system comprising: receiving means for receiving a new data unit to be stored in the storage device; monitoring means for monitoring the status of the storage device, and for generating an indication of whether there is enough free space in the storage device to store the new data unit; weighting means for, when the monitoring means indicates that there is not enough space in the storage device to store the new data, weighting data units stored in the storage unit according to a predetermined weighting system, wherein the weighting system weights the data units based on priority and age, and wherein the weighting system weights the data units in the order of high priority, new data; high priority, old data; how priority, new data; low priority, old data in terms of desirability to retain; and erasure means for deleting data units in order of weights until there is enough free space in the storage device to accommodate the new data unit.