Date: Thu, 27 Jan 2000 08:25:40 -0700
From: yodaiken@fsmlabs.com
To: Jerry Epplin <jerry@stereotaxis.com>
Subject: Re: [rtl] patent


Details of the license are being worked out by Linux International
attorneys. There has been a long delay in getting this done, because
everyone involved is way too busy and because Linus and I had discussed this
before and were in agreement.
The basic idea is that if you use RTLinux you pay no 
royalties. If you use a different "realtime" component for Linux you
also pay no royalties, but you are required to say whether or not
you are compatible with RTLinux -- where compatibility is determined
by a regression test we will provide --- and you are required to 
meet the GPL by publishing your source code on Linux Internationl
or Linux.org's web pages to make it open.  Other base OS's are not covered.

What you should think of the patent depends on who you are. If you are
an RTLinux user, or even if you use some other version of realtime Linux,
then you should be thrilled that there is some legal protection for using the
system royalty free and you should send me some money to help me pay the
extensive legal fees involved. 

If you want to use my idea for a non-Linux or non open project, you should
think about how to pay. The main purpose of the patent was defensive as I 
did not want to find myself paying royalties to someone else to use my
idea. But I have no objections to collecting fees from people who want to 
do this on Windows.


On Thu, Jan 27, 2000 at 08:19:24AM -0600, Jerry Epplin wrote:
> What are we to make of Victor's software patent "Adding
> real-time support to general purpose operating systems"
> (US patent no. 5995745)?  This patent appears to cover
> the basic principles behind RTL; including running a
> non-real-time OS as one task of an RTOS, and preventing
> the non-real-time OS from disabling preemption by the
> RTOS.
> 
> Perhaps this patent is directed toward the various
> commercial products, such as those for NT by RadiSys 
> and VenturCom.  However, it also appears to cover the 
> design of RTAI, if I understand the design of that 
> system correctly.  It would also preclude other 
> open-source designs; such as, say, a real-time FreeBSD
> based on the same principles as RTL.  Modified versions
> of RTL itself would presumably also violate the patent.
> 
> The file 'PATENT' in the 2.1 distribution contains an
> ambiguous statement which appears to grant a royalty 
> free license to certain users of RTL.  Victor,
> could you provide a clarification of this statement, 
> specifying the exact conditions under which one may 
> use the methods claimed in the patent?
> 
> Jerry
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-- 
---------------------------------------------------------
Victor Yodaiken 
FSMLabs:  www.fsmlabs.com  www.rtlinux.com
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VJY Associates L.L.C, New Mexico.

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