Thanks for the explanation. It seems to be the difference between "Open I/O" and "Open Extend". The only real acquaintance I have with data entry was a job I had in 197? where the data entry operators entered through an "Entrex" machine and the output to the computer (main frame) was on tape and there, of course, was no update directly to the tape. They stored everything on a disk and when the data entry was clean we processed the tape. The other data entry method was cards.
