Abstract: Multiple versions of a runtime system, such as a software emulation application that emulates a legacy hardware architecture, are allowed to co-exist in the memory of a new hardware architecture. The operating system software of the new hardware architecture reads configuration data from a database or table to decide which version of the runtime system is desirable for an application program or game that is being loaded or is currently running, and, if a match is found, only that runtime system is invoked. To reduce storage footprint, the different versions of the runtime system may be stored using “differential patching” techniques. In this configuration, the operating system will always launch the same basic runtime system binary, but it will select a different differential patch to apply at run-time based on the title as determined during the database lookup.

Abstract: Attempts by drivers of a virtualized legacy computer game to communicate with nonexistent legacy game system hardware are converted into calls to actual hardware of the host computer game system. An access control list (ACL) restricting and/or reducing page permissions is used to explicitly forbid the drivers of the legacy computer game operating on the virtualized legacy computer game platform from writing to the MMIO addresses of the legacy computer game system. When the operating system of the virtualized legacy computer game platform attempts to touch its driver memory by writing to the MMIO addresses, the operating system of the host computer game system perceives a memory access violation, suspends the virtual machine implementing the virtualized computer game platform, and passes the intended write to an exception handler of the host operating system.

Abstract: A compiler automatically builds a new version of an object server to be compatible with an existing version so that client applications built against the existing version are operable with the new version. The existing version object server retains type information relating to its classes and members in a type library. The compiler performs version compatibility analysis by comparing the new version object server against the type information in the existing version's type library. If the compatibility analysis determines that the new and existing versions are compatible, the compiler builds the new version object server to support at least each interface supported by the existing version object server. The compiler further associates version numbers with the new version object server indicative of its degree of compatibility with the existing version object server.