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Symbolics terminal emulator works lousy
Date: Fri, 18 Dec 87 12:57 EST
From: Barry Margolin <barmar@Think.COM>
Date: Fri, 18 Dec 87 09:38:42 +0100
a. When you reboot a Lispm and there are ftp sessions or telnet
sessions open, they get left around
This is an aspect of the Telnet and TCP protocols. There is no way to
tell whether the host at the other end of an idle connection is really
still there. Connection problems only become apparent when a host
actually tries to produce output; if TCP doesn't get an acknowledgement
after a few retries it decides that the host or network is dead, and if
it gets a TCP reset it means that the host has since rebooted or
reinitialized TCP. If the host doesn't delete the sessions when these
happen, it is a bug in the software. This is all intentional on the
part of the TCP/IP designers; it eliminates network traffic due to
packets being sent just to let the other guy know you're there, and it
makes connections tolerant of temporary network problems.
Some of the blame can be put on Symbolics. When you reboot a Lispm, the
processes that are running are not killed cleanly, so they can't close
their connections. SI:HALT doesn't kill processes because you might
want to do a Continue from the FEP. There is no command that I know of
that does a clean shutdown.
Uh, how about Logout?