Subject: Re: ptys are not always freed
To: Bill Studenmund <>
From: Jukka Marin <>
List: current-users
Date: 01/26/1998 08:11:15
On Sun, Jan 25, 1998 at 01:41:04PM -0800, Bill Studenmund wrote:
> The problem we've seen w/ AIX & pine is that the process will chew up lots
> of CPU. It seems the program is trying to write to the old output, and is
> getting stuck. It's like the scheduler pulls it up, then it decides it
> can't run, then it pulls it up, then it decides it can't run. We can end
> up with such processes taking 70 % of the CPU, when all the other uses of
> the CPU add up to about 50%.

Well, that was one problem with AIX.  The other one was that when someone was
using, say, X or dnet to log on the AIX machine (dnet is a software which
allowed for multiple logins / file transfers over a single modem line, a bit
like PPP but with its own protocol) ie. used the virtual terminal system
and then was cut off without logging off properly, the virtual terminal
would stay open and keep all the user's programs running.  When a new user
logged on, he/she was given the same pty line and BANG, without a password
or anything, he/she ended up in the program the previous user had been

Once when I logged on, I ended up in another user's elm where there was
a mail message from a third user complaining about this very same problem..

I really really don't want this to happen on NetBSD..

I don't kow how the pty stuff works, but it sounds like the other side
(slave?) pty isn't getting closed and the processes killed when the user-
side (master?) of the terminal is closed.

Sorry for the messy message, my brain is still asleep..