Corrigan@DDN3.ARPA (05/04/88)
The FTP implementation on the Honeywell mainframe done for the World-Wide Military Command and Control System (WWMCCS) implements and uses checkpoint/ restart. It also lets you begin a transfer, leave, and check back later on status. They used to move huge files in the mid/late 70's and restart was essential for operational, not cost, reasons, because the system didn't stay up long enough to complete very many transfers. The checkpoints were based o time, not number of records transfered, because the variability in throughput was high, and minimizing the amount of lost time was the important issue. I think 5 minutes between checkpoints was the default. All this continues to work as we speak -- of course the protocol it is running over is NCP...... Mike