Page "Amdahl Corporation" Paragraph 15

z / OS 1. 5 is the last release of IBM's flagship operating system still able to run on 31-bit mainframes, including Amdahl and older IBM systems.

IBM effectively ended support for z / OS 1. 5 on March 29, 2007.

In May, 2006, IBM announced that the next version of z / VSE, Version 4, would require a 64-bit system, signaling the end to 31-bit support for that operating system.

z / TPF, which became available in December, 2005, also requires a 64-bit system.

The 31-bit Linux distributions will survive as long as the open source community and distributors have interest.

So while there's still some potential life for Amdahl's hardware, the transition to 64-bit systems is essentially complete.

Some companies and governments still had Amdahl systems performing useful work into mid-2006, and Fujitsu / Amdahl promised support to those customers with replacement parts and other services through March 31, 2009.