Abstract: Each element of a database may have multiple versions; the versions are partitioned into branches, and versions of a branch are ordered linearly according to their timestamps. Branches are timestamped and related to one another by a version graph. Each version of an element of a database is represented by a unique identifier, a timestamp, a branch name and a value. A new version of an element associated with a branch is created in response to an operation associated with the branch which would modify the element. An object graph in the database is represented independent of the branches and version; an application coded for elements in one version (and branch) can be reused for the same elements in a different version and (different branch) without any re-coding effort. Methods for long duration transactions, cooperative transactions and schema evolutions are provided.

Abstract: A method of using a display system having a spatial light modulator (14) to display holographic images. The spatial light modulator (14) generates images that represent vertical strips of a hologram. These images are de-magnified by a three-dimensional optics unit (18), in the horizontal direction so as to form image strips. A scanning mirror (45) scans the image strips in a series across an image plane at a rate sufficiently fast that the viewer perceives a composite hologram comprised of these image strips.