getty/uugetty -- what is the difference, really?

[Bill Irwin]

urban at cbnewsl.att.com (john.urban) writes:

: Another difference is that getty displays the Login prompt immediately where
: as uugetty waits for some kind of input (carriage return or similar) before
: displaying the the Login prompt.

: This keeps two computers connected directly from spitting Login: Password:
: back and fourth all day.

>From what I have read, putting the flag "-r" at the end of the
inittab line is what tells uugetty to wait for <CR> before
displaying the Login:  prompt.  Leaving this flag off while make
uugetty display the prompt immediately.

Uugetty waits for carrier detect (CD) to go positive on the port,
indicating that the modem just answered an incoming call.  Until
then, the "real" part of getty (the part that displays the Login:
prompt) isn't even running on that port.  Do a "ps -ft ttyxx" and
watch no getty process appear, as they do with normal ports using
getty.

When uugetty sees CD, it then spawns the process that displays
the Login:, which is why it appears automatically just after your
modems connect, unless you have set the "-r" flag in which case
it waits for <CR>.

It may be DSR that uugetty looks for, I'm not positive.  But I do
know that the signal is not positive until the modem connects
with another modem.  You can screw this up by configuring your
modem to force CD/DSR on all the time, such that uugetty keeps
the port open and UUCP locked and UUCP will not be able to dial
out because it thinks there is a login on the port.

: John Urban
: att!attunix!jbu
-- 
Bill Irwin    -       The Westrheim Group     -    Vancouver, BC, Canada
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