If no one reply you on that old machine I can answer for ibm machine which still use card reader concept in its jcl card deck. The cards you put up with has tw

If no one reply you on that old machine I can answer for ibm machine which still use card reader concept in its jcl card deck. The cards you put up with has two // These are you control cards One of these will be program card The next card with dd * you will be your program ... An example is on p.88 of this manual http://www.computinghistory.org.uk/downloads/9041 http://www.computinghistory.org.uk/downloads/9041 , in fact follow up you have many details.