Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!pasteur!ucbvax!DDN3.ARPA!Corrigan
From: Corrigan@DDN3.ARPA
Newsgroups: comp.protocols.tcp-ip
Subject: FTP Checkpoint
Message-ID: <8805040532.AA25778@ucbvax.Berkeley.EDU>
Date: 3 May 88 17:02:00 GMT
Sender: usenet@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 12

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