[freetds] TDS versions

James K. Lowden jklowden at freetds.org
Wed May 28 12:01:54 EDT 2008

Emil Wojak wrote:
> the recently revealed documentation was publicly available since
> January 2008 in form of a patent

It's important to be clear and specific in this area.  The issues are
complicated and deeply technical, traversed by lawyers and nonlaywers
ill-equipped to understand them.  

Patent 5,974,416 is described and referenced here in my letter to Fedora:


Patent 5,974,416 does not apply to anything FreeTDS does or ever will do. 

Patent 7,318,075 "Enhanced tabular data stream protocol": 


Patent 7,318,075 describes protocol enhancements that appeared with SQL
Server 2005.  Its claims include MARS and password modification.  These
features are not part of FreeTDS.  And, it would seem, never will be.  

Thank you for pointing out this patent.  I wish I'd never read it.  It
means that Microsoft is patenting its changes to the protocol.  It is the
first step to preventing the creation of a compatible, interoperable
implementation of their protocol.  

Microsoft has had, up until now, little choice but to tolerate the FreeTDS
project.  Requests for cooperation and documentation came to nothing,
despite the usefulness of the project in promoting use of SQL Server.  

Make no mistake, though: absent a license, patent 7,318,075 prevents
FreeTDS from implementing a fully functioning, fully compatible free
client for SQL Server 2005 and beyond.  I do not expect a license to be
granted on terms compatible with the LGPL; such terms would make the
patent worthless.  


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