The general form of the Allocate Device command is: ALL[OCATE] dd[nn:] [=llnn:] ALLOCATE establishes the specified device as the user's private device on multiuser protection systems.. The LLnn: keyword allows the user to equate a physical device with a logical device. Specifying the command with only a 2 character abbreviation allocates the first free device of the type specified. Mounted devices, public devices, or other users' private devices cannot be allocated. The system automatically deallocates a user's private devices when the user logs off.