Abstract: Smooth release of resources on a switch node adapter to a diagnostics program is provided without requiring rebooting of the system. The release technique includes: setting a first flag at a device driver associated with the adapter to block new open system calls from opening the device driver; broadcasting an adapter down event to instruct internet protocol (IP), fault service daemon (FSD) and application program interface (API) components of the node to release resources on the adapter; and setting a second flag at the device driver to block input/output control calls other than from the diagnostics program. When the device driver supports multiple adapters, only the adapter undergoing diagnostics is suspended, the remaining adapters remain up to components of the switch node. Upon completion of diagnostics, components remaining in open state are restarted on their communication windows at the adapter.