Re: patent on O_ATOMICLOOKUP [Re: [PATCH] loopable tmpfs (2.4.17)]y

Der Herr Hofrat
2002-05-26T10:08:23Z

> > >
> > > There was one more match that was publicly claimed as copying by
> > > the maintainer of RTLinux -- a few fields in the scheduler structure.
> > > The script caught those, too, once I set the threshhold down to 3
> > > lines, which also picked up hundreds of mismatches.
> >
> > Good luck making that stick in court. First of all, the RTAI guys have
> > admitted over and over that RTAI is a fork of the RTLinux source base.
>
> Paolo (the maintainer) hasn't. I (the second largest contributor)
> hasn't. I understand why others talk about RTAI and RTLinux forking,
> since the _projects_ forked, and the _ideas_ forked, but the _code_
> was always separate. At some point, a person gives up trying to
> argue the point, and just says "it forked". But when you get down
> to brass tacks, there was no code fork, because there was never one
> code base.
>
> There was some sharing of code in the beginning, typically code that
> was sent to the RTLinux mailing list by third parties. In that case,
> the code was copyrighted by the individual. The fact that it later
> showed up in RTLinux as "copyright VJY associates" does not change
> the fact that Paolo got it from the original author.
>

david - you know the code.

rtai-24.1.6a/fifo/rtai_fifos.c:line 25-31:

*/
ACKNOWLEDGEMENT NOTE: besides naming conventions and the idea of a fifo handler
function, the only remaining code from RTL original fifos, as written and
copyrighted by Michael Barabanov, should be the function "check_blocked"
(modified to suite my style). However I like to remark that I owe to that code
my first understanding of Linux devices drivers (Paolo Mantegazza).
/*

in rtai-1.6:oldfifos/rtai_fifos.c:line 1-9:

/* Modification of RTL-FIFO devices by Paolo Mantegazza */
/* The original RTL_FIFOS are developped and copyrighted by Michael */
/* Barabanov, 1997, who derived them from fs/pipe.c in Linux, which is in */
/* turn copyrighted with "Copyright (C) 1991, 1992 Linus Torvalds". */
/* This modified version is for use with the RTAI module. It works in the */
/* same way as its original counterpart, but now you can chose either a */
/* task queue for bottom halves or an immediate wake up, plus assigning a */
/* static user buffer. */
/* See functions: rtf_create_using_bh and rtf_create_using_bh_and_usr_buf. */

In my opinion it is obvious that the RT comunity that was RTLinux and RTAI for
quite a while was "stealing" ideas and code from each other - and that is a
very good thing to happen in GPL'ed environments, there was for a long time
one mailing list and that was being shared in a productive manner by both
groups. The fact that the two groups splitt up and are fighting each
other is what is really hurting both sides a lot and probably also hurting
Linux in the market that has interest in hard-realtime.

hofrat