We have adapted an interactive programming system (Smalltalk) to a multiprocessor (the Firefly). The task was not as difficult as might be expected, thanks to the application of three basic strategies: serialization, replication, and reorganization. Serialization of access to resources disallows concurrent access. Replication provides multiple instances of resources when they cannot or should not be serialized. Reorganization allows us to restructure part of the system when the other two strategies cannot be applied.