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From: rubinoff@linc.cis.upenn.edu (Robert Rubinoff)
Newsgroups: comp.sys.mac
Subject: Re: Undefeatable Vaccine??
Message-ID: <12273@netnews.upenn.edu>
Date: 21 Jun 89 20:22:19 GMT
References: <12270@netnews.upenn.edu>
Sender: news@netnews.upenn.edu
Reply-To: rubinoff@linc.cis.upenn.edu (Robert Rubinoff)
Organization: University of Pennsylvania
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In article <12270@netnews.upenn.edu> pakman@scrolls.wharton.upenn.edu (David B. Pakman) writes:
>I have heard that someone at the University of Michigan has created
>a version of Vaccine that is un-defeatable.  

Don't believe it.  Any protection scheme can be defeated by a sufficiently
clever and determined programmer.

Now, if what you want is just a version that can't be turned off by the user,
that can be done to varying levels of sophistication.  All of these ideas can
be undone by a determined student, but they'll prevent casual disabling:

 - change the file type from cdev to INIT, so it won't show up in the control
panel.
 - make the file invisible, so the students can't drag it out of the system
folder.
 - copy the resources into the system file so that there isn't a separate file
for the students to remove.

I haven't tried any of these, so I don't know if they'll cause problems 
(although making the file invisible should be harmless), but they're possible
options.  Whether they'll be any use depends on how resourceful (so to speak)
the users are, which you'll have to judge for yourself.  And of course nothing
will help if people boot off their own floppies.

  Robert