The fundamental second-system effect to challenge Copland's development and adoption would be getting all of these functions to fit into an ordinary Mac. System 7.5 already uses up about 2.5 megabytes (MB) of RAM, which is a significant portion of the total RAM in most contemporaneous machines. Copland is two systems in one, as its native foundation also hosts Blue Box, containing essentially a complete copy of System 7.5. Copland thus uses a Mach-inspired memory management system and relies extensively on shared libraries, with the goal being for Copland to be only some 50% larger than 7.5.