,---- | When it comes to GNU/Linux, I don't think that it's advisable to | specifically mention the name of the program. I mean, what if the | company decides to discontinue the GPL for the particular package? | Obviously, it would be illegal to still distribute the software which in | turn would make the references in the books obsolete. An example would | be Star Office. How long is abiword,gnumeric etc going to be free? `---- A particular version of a Software once released under GPL cannot be taken back. How ever its future versions can go propeirtary. We are left with the choice of sticking to the version released under GPL or hire some programmers to compete against the proprietary branch and maintain it.