I still don&#x27;t know the answer:<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;History_of_IBM#1969:_Antitrust.2C_the_Unbundling_of_software_and_services" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;History_of_IBM#1969:_Antitrust...</a><p>&quot;After the unbundling, IBM software was divided into two main categories: System Control Programming (SCP), which remained free to customers, and Program Products (PP), which were charged for.&quot;<p>So what were Amdahl&#x27;s customers able to get? Didn&#x27;t they get System Control Software from IBM (1)? Was it free for them?<p>1) I&#x27;ve found the Computerworld 1 Nov 1976 article mentioning IBM&#x27;s MVT 21.8 running on Amdahl&#x27;s 470.