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From: tim@cit-vlsi.Caltech.Edu (Timothy L. Kay)
Newsgroups: comp.arch
Subject: Re: Cloning the new IBMs without violating copyrights
Message-ID: <2522@cit-vax.Caltech.Edu>
Date: Wed, 29-Apr-87 21:40:30 EDT
Article-I.D.: cit-vax.2522
Posted: Wed Apr 29 21:40:30 1987
Date-Received: Sat, 2-May-87 04:27:44 EDT
References: <766@vaxwaller.UUCP> <2643@phri.UUCP> <3087@diku.UUCP> <489@bloom-beacon.MIT.EDU>
Sender: news@cit-vax.Caltech.Edu
Reply-To: tim@cit-vlsi.UUCP (Timothy L. Kay)
Organization: California Institute of Technology
Lines: 24
Summary: Defeating copyright notice protection

In article <489@bloom-beacon.MIT.EDU> wesommer@athena.mit.edu (William Sommerfeld) writes:
>In article <3087@diku.UUCP> thorinn@diku.UUCP (Lars Henrik Mathiesen) writes:
>>  When you use a System/2 as terminal equipment against an IBM mainframe, one
>>of the commands in the protocol says "Please send the copyright message in
>>your ROM;" the mainframe checks this against whatever it is on a System/2,
>>and won't communicate if it's not the same.

>How about this:  Embed the following message in the ROM:
>
>Copyright (C) 1987 Clonz-R-Us.  We did this one ourselves with no help
>from Big Blue - It's not Copyright (C) 1987 IBM.  All rights reserved.
>
>where "Copyright (C) 1987 IBM.  All rights reserved." is the string
>one needs to include in the protocol... and only send the last part over.

The problem here is that the software will look in a fixed place in the
ROM.  So, you have to have the IBM copyright notice in the correct place.
Is there a legal reason that people can't put this there?

Here is a work around:  Put an encrypted version of the IBM copyright
notice in the correct place in the ROM, and have a circuit in the clone
that decrypts just that part of the ROM when a certain bit is set.  So,
the defacto ROM contains only gibberish.  However, before you run the
IBM'd program, you have to turn on the decryption.