Tridia VNC

Michael Ossmann michael.ossmann "at"
Thu, 07 Mar 2002 17:37:09 +0000

On Thu, Mar 07, 2002 at 03:01:01PM +0530, Jasmeet S. Virdi wrote:
>     Just saw TridiaVNC Pro. i have a question. Since TridiaVNC Pro is
>     based upon VNC, which is open source under GNU license, won't it
>     be mandatory for TridiaVNC people to make it open course too ??
>     And do they have to make it free too ?? (they already have a
>     product TridiaVNC, which is free, its the pro version that is not
>     free and contains additional features..)

According to :

  Is TridiaVNC Pro open source software?

  No. Although the TridiaVNC components are all open source and
  licensed under the GPL, the TridiaVNC Pro components are closed
  source. While commercial or closed source software may not link with
  the open source software, there is no restriction from bundling and
  shipping open source software in a commercial product. Many hardware
  manufacturers include open source software with their own closed
  source program packages.

Personally, I suspect there is a GPL violation going on here.  In fact,
I'm fairly certain of it.  TridiaVNC (or at least components of it) are
distributed as a part of TridiaVNC Pro.  It even installs a TridiaVNC
subdirectory which includes a copy of the GPL.  However, the GPL reads:

  0. This License applies to any program or other work which contains a
  notice placed by the copyright holder saying it may be distributed
  under the terms of this General Public License.  The "Program", below,
  refers to any such program or work, and a "work based on the Program"
  means either the Program or any derivative work under copyright law:
  that is to say, a work containing the Program or a portion of it,
  either verbatim or with modifications and/or translated into another

TridiaVNC Pro looks like a derivative work to me.  Even if they could
somehow prove in court that it is not a derivative work, there is a
problem with the click-through license in the TridiaVNC Pro installer.
It removes many of the freedoms granted by the GPL for the entire piece
of software without any exclusions for the open source components.

Mike Ossmann, Tarantella/UNIX Engineer/Instructor
Alternative Technology, Inc.
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