LTFS10004E Cannot open device 'STRING1'

Explanation
      
    The device 'STRING1' cannot be opened.
  

  
Operator response
      
    Verify that the drive is powered on and connected to the system. The tape drive must be powered on prior to powering on the system or the tape drive cannot be recognized. If the tape drive is used by another program, unmount or release the drive from the program.