IBM let loose a fusillade of legal firepower today aimed squarely at blowing away SCO. The computer giant, considered three decades ago to be the most controlling, powerful, and anti- competitive company in the industry (like Microsoft is today) is in the interesting position of being the "defender of the faith" for millions of Linux supporters.

According to this article from CNet, the company has filed an extensive 45-page counter-complaint (thanks to Computer Reseller News, tiff format, and here's a PDF that I built) with many parts.

The counterclaim contains a variety of assertions, including:

• Four patent claims against SCO claiming that four software packages (UnixWare, OpenServer, SCO Manager, and Reliant HA) violate separate patents owned by IBM (consistently issued more patents than any other company in the world).
• A claim that SCO signed away all rights to their contributed code by contributing it to the Linux codebase.
• A claim that SCO interfered with IBM's business by publicly claiming that they had no license for AIX.
• Claims that the AIX code contributed to Linux by IBM is not a derivative work of UNIX.

Particularly amusing is a claim (backed up by documentation from the Novell/SCO agreement and memos from Novell) that Novell told SCO on June 12 that they could not terminate IBM's license. It turns out that under the original Novell/SCO agreement, Novell could amend any existing agreement in just about any way at any time and SCO would have to comply.

SCO, of course, claims that the terms are void because IBM violated SCO's rights.