## Physical Device Driver Reference

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### DEV_SYSTEMNOTIFYPDD (41h) - Action

Action Contains a value indicating the notification-calling condition. Action is a bit map that describes the type of notification made to the physical device driver. The bit-map definitions are as follows:

Bits 15-9 Reserved. Must equal 0.
Bit 8 Action = 256. AIM post-save activation
Bit 7 Action = 128. AIM pre-save verification
Bit 6 Action = 64. End of session switch
Bit 5 Action = 32. Start of session switch
Bit 4 Action = 16. Session creation
Bit 3 Action = 8. Session termination
Bit 2 Action = 4. Post-session restore
Bit 1 Action = 2. Post-session save
Bit 0 Action = 1. Pre-session save

Physical device drivers can register for any combination of these notification values by issuing the DOSSMRegisterDD API function. If a physical device driver receives a notification with an Action value it does not support, it returns an ERROR_INVALID_PARAMETER error code.