Int 7A Fn 09  - Ibm 3270 Workstation Program Api - Operator Information A  [I]

   AH = 09h
   BX = 8020h
   CX = 00FFh
   DX = ID of OIAM
   AL = service
       01h read Operator Information Area
       02h read OIA subset
   ES:DI -> control block

Return: ???

Note: the OIA is the 25th line on the Host session