The inventions relate generally to layered computing systems that provide public access to the content of the layers. Also disclosed herein are prioritization schemes usable in a layered computing system, including prioritization by layer type, by assigned priority weights, by access type, by sub-layers and by read-write indicators. Processes may further be associated to layers from which they originate, and priority given to associated layers thereby. Association may also be provided for installer services, thereby depositing an applications updates into its layer. Layers may also contain file reference information including exclusion or inclusion entries indicating what files may be written thereto. Paths recorded in layers may also embed variables to true paths on a layered system. Detailed information on various example embodiments of the inventions are provided in the Detailed Description below, and the inventions are defined by the appended claims.