Path: utzoo!utgpu!cunews!cognos!geovision!pt
From: pt@geovision.gvc.com (Paul Tomblin)
Newsgroups: comp.lang.c
Subject: Re: exploding software
Message-ID: <1584@geovision.gvc.com>
Date: 24 May 91 12:00:12 GMT
References: <1991May23.221811.21343@agate.berkeley.edu>
Reply-To: pt@geovision.gvc.com
Distribution: na
Organization: GeoVision Corp., Ottawa, Ontario
Lines: 31

cnrdean@cavebear.berkeley.edu writes:


>Anybody know of some standard C code (I need it for Turbo C)
>that will make a program not work after a particular date?

The best, and only unbreakable method of doing this is to fire up
your trusty word processor, and send them a letter saying that 
after that date, you are not going to provide tech support, upgrades,
and all the other stuff that a REAL program should come with.

(If it doesn't come with that stuff, why would people pay for it,
since any copy protection can be broken)

TRUE STORY:
At my last job, we had an evaluation copy of MOSS (a terrain modelling
system), that we were licensed to use for one pilot project, finishing
at a certain date.  Well, due to political reasons, the project went 
over time, but we didn't want MOSS to stop working.  We suspected that
the MOSS evaluation copy had one of these stupid "stop working after
such-and-such-date" routines in it, so we wrote a
dummy versions of all the routines that return the system date, and
patched the executable.  It then continued for the rest of the pilot,
at which point we got authorization to get the REAL version.

So much for trying to make programs blow up at a certain date.
-- 
Paul Tomblin, Department of Redundancy Department.       ! My employer does 
Two roads diverged in a wood, and I/ I took the one less ! not stand by my
travelled by/ And that is why I'm lost, dammit...        ! opinions.... 
pt@geovision.gvc.com or {cognos,uunet}!geovision!pt      ! Me neither.