The Northern Telecom SL-10 Packet Switching System is steadily enhanced to provide better access services for users. Equally important to them, but less visible, are enhancements to improve availability and increase throughput. To this end, intelligent peripheral devices, such as storage controllers and line servers, have been added to the Switch and new strategies, especially for software loading, have been devised. Such additions have had an impact on the software architecture. The Resource Subsystem now has to cope with a wider variety of devices, including intelligent peripheral devices. The File Subsystem has been generalized to accommodate files on different types of volumes, e.g., disks and tape cartridges. A whole new Subsystem has evolved to handle strategies for loading processors in parallel and to load intelligent peripherals. The SL-10 Packet Switch software architecture, with its process environment structured in Subsystems, has proven well suited to these requirements.