Patent ID: 6581143
Filing Date: 2003-06-17
Classification: G06F

Abstract:
In a data processing system in which a first application program is adapted to interact with data in a first storage device located on a first physical disk storage unit, a control for enabling at least two additional programs to interact concurrently and independently with copies of the data stored in the first storage device, said control comprising:A) device identification means for identifying additional storage devices on different physical disk storage units for each of the additional programs, B) session reference means for defining a session reference for each of the additional storage devices, each session reference having entries for recording each change made to a corresponding portion of the data on the first storage device, C) recording means for recording each change to a data portion on the first storage device in the corresponding entry of the session references, D) device reference means for defining a device reference for each of the first and additional storage devices with entries for recording each change a respective program makes to a data portion, E) copy generation means for generating independent copies of the data in the first storage device on the other storage devices for interaction with the respective additional programs, F) device change recording means for recording in said device reference means each change each additional program makes to a data portion stored in its respective storage device, G) updating means for updating data portions on a selected one of the additional storage devices on demand by combining the entries in said corresponding session and device references to identify changed data portions, and H) copy means for copying the changed data portions from the first storage device to the selected storage device.