Method and system for managing data in computer memory

This invention relates generally to the field of computer systems, and, more particularly, to the management of data residing in computer memory devices. A system for managing space in a computer memory is disclosed. The system creates free space in a computer memory by using a "downsize" operation, which selectively removes data from a data object residing in the memory. Each data object in the memory provides a downsize operation designed for that data object, which reduces the amount of space that the data object occupies in the memory by deleting data that can be recreated from another source, or data that is not essential to the function of the data object. Each data object may also provide a "restore" operation, which returns the object to a usable state in the memory by replacing data in the memory that has been removed by a prior downsize operation. The restore operation is used if an attempt is made to access the data object after it has been downsized. The system can be used to manage various types of memory containing various types of data objects. One use of the system is to manage the space on a personal computer hard disk by downsizing applications on the disk when additional disk space is needed and then restoring a downsized application when a user attempts to run it. Another use of the system could include management of a database on a storage medium by deleting portions of the database that have been archived on another medium and retrieving portions from the archive on an as-needed basis.