Path: utzoo!mnetor!uunet!husc6!mailrus!nrl-cmf!ames!oliveb!intelca!mipos3!cadev4!dbraun
From: dbraun@cadev4.intel.com (Doug Braun ~)
Newsgroups: comp.sys.ibm.pc
Subject: Re: F-15 Strike Eagle
Message-ID: <1708@mipos3.intel.com>
Date: 17 Feb 88 16:48:46 GMT
References: <3037@cup.portal.com> <3186@cup.portal.com>
Sender: nobody@mipos3.intel.com
Reply-To: dbraun@cadev4.UUCP (Doug Braun ~)
Organization: Corporate CAD, INTeL Corporation, Santa Clara, CA
Lines: 31

In article <3186@cup.portal.com> Don_C_Rudolph@cup.portal.com writes:
>Sorry folks, but I put out some bad info over the net.  I described my
>F-15 Strike Eagle diskette as having a hole in it.  Well, I just found
>out that all floppies have that hole.  It is called it a reference
>hole.  I've just never noticed it before.  How do you make an
>embarassed happy face?
>
Actually, having an extra index hole could be an excellent method
of copy protection.  An extra hole wouldn't affect normal operation
because it is only used to tell if the disk is spinning, and during
formatting.
    The scheme would work like this:  The program tries to
read a non-existent sector.  Normally, the controller chip tries
to read until the disk has gone through N revolutions, as determined
by counting index marks.  With an extra hole, there will be twice as many
index marks, so the controller times out in N/2 revolutions.
The program just keeps track of this time, and if it is too long
(i.e. not shortened by an extra hole) the program exits.

This might bomb on ATs, etc., though.



Doug Braun				Intel Corp CAD
					408 496-5939

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