Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!caen.engin.umich.edu!conliffe
From: conliffe@caen.engin.umich.edu (Darryl C. Conliffe)
Newsgroups: comp.sys.apollo
Subject: Re: Processes in GPR_$borrow mode.
Summary: Perhaps an alternative
Message-ID: <43d95d4b.b11a@falcon.engin.umich.edu>
Date: 15 Jun 89 17:51:00 GMT
References: <8906150509.AA02550@umix.cc.umich.edu>
Organization: U of M Engineering, Ann Arbor, Mich.
Lines: 42

In article <8906150509.AA02550@umix.cc.umich.edu>, GBOPOLY1@NUSVM.BITNET (fclim) writes:
> >From: conliffe%caen.engin.umich.edu%mailrus.uucp@bbn.com  (Darryl C. Coliffe)
> >> However, because root overrides all permission modes, when root issue
> >> a write(1) or wall(1), the message will still get thro.
> >>
> >
> >NO NO NO!  Please don't forget that some people DO use borrow mode
> >for a reason, and undesired information appearing at unexpected times o
> >a workstation screen can ruin work, too!
> 
> Yes I agree; breaking in GPR_$borrow mode violates the very idea of
> Dennis Cottel's gone program which locks the node using GPR_$borrow mode.
> 
> *However*, please note that I have qualified myself by saying that I need to
> know
> how a superuser like root or user.sys_admin may break into the borrow mode.
> Not every Tom, Dick and Harry should be able to do that.  And a supervisor
> only do it if there's an urgent message need to send via send_alarm.

I reiterate that there is the possibility that such a user may
destroy valuable work in progress, and thus should use a phone
or walk over to the station.  (Just kidding, I *KNOW* you can't do that
*ALL* the time ;=).

However, if the objective is to signal a very important condition
that needs user attention, then a routine that rings the bell of
the workstation, obnoxiously and repeatedly until acknowledged
may be your answer.

BTW, I am not considering Cottel's gone program in the class of
"don't interrupt" routines.  I think an installation should modify
gone to make it interruptable via root and/or sys_admin.  It's
CAD, visualization, or rendering applications I think should be
protected.

Vendors could help by not using borrow mode in their designs, but that's
a different train of thought.
-- 
___________________

 Darryl C. Conliffe  conliffe@caen.engin.umich.edu  (313) 721-6069
-------------------