What is "Connection Closed by OS" caused by?

BobS

I just lost a print due to "Connection closed by OS" after 80-hours into a 96-hour print.

1st... is there a way to recover from this and restart like after a power failure?
       (This computer and Printer are on a BIG UPS to prevent power issues from messing up long prints)

2nd... what caused it and how do I prevent it?

I did notice that every once in a while everything would PAUSE, no error messages I could see, and after a few MINUETS it would pick up where it paused and just keep going.  If I paused (from either the printer or Repetier) and then continued it would again pickup where it paused and keep going....   Is there a "master" connection error count that is ctops after exceeding for timeouts or pauses?

Repetier

When os closed connection often the usb hub disconnected the printer due to emf/power usage. On linux check syslog at same time for details. There is an optien to continue after this which you seem to have active if print continues after printer is back. In contrast timeouts come normally from communication errors but you need to enable logging and check it if it was the reason.

You can continue if you have enabled and configured our rescue system. Works only if position is known or can be figured out by homing xy and set z to last position. If the printer does not allow this e.g. preventing y moves without homing this will not work.