The company I work for uses a proprietary ERP system
that the users connect to using a telnet client (Appgen). We also have
forklift operators driving around using radio links via another telnet application.
The ERP system uses a somewhat antiquated architecture and gets very sad about
locked records if a user terminates a session either by dropping out of the
radio link or just getting impatient because a report is taking too long and
doing End-Task. address@hidden In both cases a session can be left “attached”
(theoretically speaking) but not in a manner that we can do anything about.
I’m investigating the use of screen to
alleviate some of these problems (or at least alleviate the consequences).
- I modified a
forklift driver’s .profile to do a screen –list and look for
the word “Attached”. If it is found then it does a
screen –x to attached to the dropped session, otherwise it runs
screen and invokes the ERP system. This works ideally! Now
thinking ahead, it’s possible that a forklift driver may go to lunch
or even go home whilst he has a
dropped session, so I would like his supervisor to be able to do the
attach so I started checking out the add* commands. At the very
least I’d like we IT people to be able to attach by logging in as
root so I did this and tried invoking screen’s (not unix’s) su
command. It prompted me for the user name and unix password and then
prompted me for the screen password. I tried leaving it blank,
entering the word none, entering the same password as the unix password,
but in all cases screen replied with Sorry. How can root attach to a
general user’s session?
- As a variation on
the theme of the above case, when the forklift driver goes to lunch he may
not log out. When he comes back if he is assigned to a different
forklift that is not logged in then he will log in and his .profile as it
stands will detect the “Attached” session and attach to it,
but of course this will go multi-user on the live connection so when
another driver jumps on the original forklift the two drivers will be
fighting for control of the one session. How can I tell if an “Attached”
session is the result of a dropped radio link or if it is live?
Thanks
Wayne Ivory
Senior Analyst Programmer
Electronic Business Development
Wespine Industries Pty Ltd