Am Mittwoch, den 29.06.2011, 16:37 +0200 schrieb Peter Åstrand: > On Tue, 28 Jun 2011, Jürgen Lüters wrote: > > > copyright law at least in europe, northamerica and japan protects the > > work computer program in our case. The law does protect programms in > > binary and text form. > > The law does _not_ protect ideas and concepts. > > > > Several programs can implement the same algorithms. As long as the > > implementation is different there is no problem. That the implenmtation > > is different can be shown by source code comparison. Clean room > > The fact the the "implementation is different" does not mean that you can > escape the copyright. This "different implementation" may still be based > on earlier, copyrighted work. A source code comparison may not show this. You can. If you copy a work and rename small parts of it (var's) it is not a different or better independant implementation.
> I'll give you an example. I downloaded ESR:s "hexdump 1.7" from > http://www.catb.org/~esr/hexdump/. The C file is 289 lines long. Then, I > changed a few variable names, removed the comments, changed the order of > the include files and a few other trivial changes. With just these small > changes, the "comparator" can no longer find any common code segments: > > #SCF-B 2.0 > Filtering: language > Hash-Method: RXOR > Matches: 0 > Merge-Program: comparator 2.8 > Normalization: line-oriented > Shred-Size: 3 > %% > hexdump-mine: matches=0, matchlines=0, totallines=277 > hexdump-1.7: matches=0, matchlines=0, totallines=627 > %% > That does show that every programm has its limitations. > Does this mean that the code is now mine, that I can put my own copyright > on it, that I can use it without obeying the original license, and that > Eric S Raymond can no longer claim any copyright on it? No. I used his > work to create "my different implementation". This means that I must still > respect his copyright. An implementation which is based on a former implemtentation is, by definition, a derived or modified work. A different or independant implementation is, by definition, not based on any other work. > So to "work on making FreeRDP show 0% match with rdesktop" does not really > help. Even if you reach this goal, the code would still be based on > earlier copyrighted work, and the GPL must still be respected. > The first step is to identify the low hanging fruits. Comparator gives you that. If you haved passed that stage, given the history of freerdp, a second pass, manual inspection with focus on obfuscation techniques seems usefull. Redardless of the more theoretical aspects, comparator has shown that some parts of the current freerdp implementation is based on rdesktop sources, as i have shown in this thread. I have found modified parts in freerdp which are, to my understanding, based on your work (e.g. rdesktop.c). That has to be resolved. > > Rgds, > --- > Peter Åstrand ThinLinc Chief Developer > Cendio AB http://www.cendio.com > Wallenbergs gata 4 > 583 30 Linköping Phone: +46-13-21 46 00 -- Jürgen Lüters Von der Handelskammer Bremen öffentlich bestellter und vereidigter Sachverständiger fuer Systeme und Anwendungen der Informationsverarbeitung Buero Hamburg Habichtstr. 41, 22305 Hamburg fon: +49-40-6113-5190 fax:+49-40-6113-5191 Buero Bremen Fahrenheitstr. 1, 28359 Bremen fon: +49-421-2208-171 fax:+49-421-2208-150 ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2d-c2 _______________________________________________ Freerdp-devel mailing list Freerdp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freerdp-devel
