When pinning is not required

UCB pinning is not required if the program accessing the device can guarantee that the device will not be deleted while the program is accessing the UCB. A program can guarantee that the device (and thus the UCB) will not be deleted if:

• The environment is one in which dynamic I/O configuration changes cannot occur.
• The device cannot become unallocated and enter the offline state while the work unit is accessing the control structures that represent the device.
• The program receives a UCB address for the device as input, but does not invoke any asynchronous processing requiring that UCB address.
  Note: In this case, the calling program is responsible for pinning or allocating the UCB.