Abstract: A computing device is configured to operate as a server in a cluster system. The computing device includes a controller, a local memory and a communications interface. The communications interface is configured to connect to a second computing device and to connect to a shared memory configured to store data. The controller is configured to receive a command from a client and determine redo and/or undo information relating to the command. The controller is further configured to store the redo and/or undo information in the local memory and to store the redo and/or undo information in the local memory of the second computing device, thereby mirroring the redo and/or undo information, where the local memory is a persistent memory.

Abstract: A system, method and medium for configuring an item such as a machine having multiple optional components is provided. This is accomplished using “options,” which correspond to the optional components of the machine, and are selected by a user according to those optional components that the user desires to have as part of the machine. Each option is envisioned to be created to contain the necessary properties (such as attributes and constraints) to appropriately configure the corresponding optional component within the machine. Embodiments of the present invention envision that the options can be arranged in a hierarchical option tree to help allow a user to better visualize the structure of the machine in making decisions concerning configuration.