On 1 Feb 2021, at 10:36, Matteo Panella wrote:
recently I tried to play around with MTS again and I decided to set it up using Hercules 4.3. Long story short: after a few minutes the OPERATOR task on DS01 dies and asks for a 9-track tape for dumping (after cancelling the dump and restarting the task from CON1 it seems to work without too much trouble).
I finally ran into this myself. I took a look at the jobdump produced (it's the first time I've done that in over two decades) and I think I know what is happening. In some rare cases Hercules is returning zero bytes of data for a 3270 "read modified" command. This is not legal. A read modified should always return at least 3 bytes (an AID and two bytes of cursor location). The operator job crashes if a read modified returns zero bytes. So there are really two bugs here: Hercules shouldn't return zero bytes for read modified and the operator job shouldn't crash if it does. The fix for the operator job is simple, but I don't think it is easy (or even possible) for you to rebuild it. I'll see if I can find why Hercules is doing this and see if there is a simple fix.
Mike
