INPUT/OUTPUT CONTROLLER

PURPOSE:To attain the report of the sense data with the start of a command at the next execution of a job by turning on an active switch even in a sense byte holding state after the occurrence of a fault. CONSTITUTION:When a READY switch is turned on, a READY state production part 4 reads the state of the READY switch and turns on a READY flag to give an instruction for lighting a READY lamp. If a command is received from a host device 1 under such conditions, a state byte production part 5 and a state byte report part 6 work. Then the channel end and the device end of a state byte are reported as long as the READY flag is kept ON. Hereafter the part 4 turns off the READY flag when a STOP switch is turned on. At the same time, an instruction is produced to turn off the READY lamp. When an error occurs while an input/output controller 2 is kept in a stop state, a sense byte is produced and a sense byte holding flag is turned on.