Two letters written by Novell chairman and CEO, Jack Messman, to SCO president and CEO, Darl McBride, in June throw an entirely different light on the lawsuit between SCO and IBM, which the former initiated in March. Both letters were cited by IBM as exhibits last week when it counter-sued SCO, on a range of issues. The letters indicate that SCO has no contractual right to terminate IBM's AIX licence. The agreement under which IBM acquired these rights appears to have been a three-way contract under which Novell retained certain rights, one being the right to compel SCO to waive or revoke any of its (SCO's) rights under the contract. In the mid-1980s, IBM acquired rights to use Unix following agreements with AT&T Technologies. In 1993, Novell acquired AT&T Technologies' rights to Unix.