Patent ID: 8291407

Claim:
A method, comprising: virtually installing a computer program patch to a computing device having a base file system and configuration, a computer program, and a patch layering subsystem, said step of virtually installing said computer program patch including: creating a patch layer that is isolated from said base file system and configuration such that patches stored to said patch layer are virtually installed and contents of said base file system and configuration are preserved instead of being overwritten; storing content of said patch to said patch layer, and generating and storing mapping data defining at least one relationship between said content in said patch layer and content of said base file system and configuration; and enabling said patch layer, including applying said mapping data to said patch layering subsystem such that said patch layering subsystem, while enabled, is configured to intercept access requests and selectively redirect the access requests from said base file system and configuration to said patch layer, wherein said patch layering subsystem does not redirect the access requests when said patch layer is disabled.