TCP/IP terminalservers and BREAK(/^C)


Heinz Naef (mcvax!cernvax!cgch!cgcha!whna@uunet.uu.net)
25 Oct 88 08:51:01 GMT


Assume a VT-100-type terminal accessing a UNIX host in the following ways:
(1) via a TCP/IP terminalserver networked with the target host
(2) via an asynchronous line interface integrated in the target host

There is a significant difference in how a BREAK (CTRL-C) condition is
handled:
In case (1) the terminalserver (3Com/Bridge LS/1, Cisco xSM) continues to
empty its buffer towards the terminal.
In case (2) the output to the terminal stops immediately.

On a UNIX system, try to cat /usr/dict/words with the two attachments
described above. In case (1) tens, hundreds of pages will be displayed
after hitting BREAK (or ^C), which is considered a problem of acceptance.

What is the reason of this different behavior? Would there be no way to
"rollback" the current buffer's worth of packets upon receiving a BREAK
and just flush the buffer?

Thanks in advance for any comments.

Regards,
Heinz Naef, c/o CIBA-GEIGY AG, R-1032.5.58, P.O.Box, CH-4002 Basel, Switzerland
UUCP: cgch!whna - Internet: whna%cgch.uucp@uunet.uu.net
BITNET: whna%cgch.uucp@cernvax.bitnet



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