public Event addIoRequest(Process requestingProcess, long clock) {
        // TODO: addIoRequest, correct?
        ioQueue.add(requestingProcess);

        /* Process left CPU */
        requestingProcess.leftCpu(clock);

        /* Initiate I/O operation if device is free */
        if(activeProcess == null){
            return startIoOperation(clock+requestingProcess.getTimeToNextIoOperation());
        }

        return null;
    }