z/Architecture CPU

In simple terms, this is 64-bit s390. But in practice, it is the architecture of IBM's zSeries of mainframes designed to replace their System 390 mainframes

zSeries 900
zSeries 800
zSeries 990
zSeries 890
System z9
System z10
zEnterprise System (z196)
zEnterprise System (zEC12)

z/OS is the recommended operating system offered by IBM for these mainframes. However, they happily support customers who wish to run a 64-bit Linux distro instead. Additionally, these machines are quite capable of, in fact designed to, run multiple operation systems concurrently. Both operation systems and software are able to run in any addressing mode they desire. Presumably, this combined functionality makes the system very nice for running legacy software for older operation systems, machines, emulators and virtual machines along side the latest software for z/OS and Linux. For UVL, Linux games are likely the only z/Architecture games we will ever have.