Re: As a consumer - 2 key issues ...
>(cf.IBM - can you still run VM/360 code on a iSeries ?)
Not an iSeries, but a zSeries. And, it's VM/370 code, since the S/360 didn't support virtual storage (well, excepting for the S/360 model 67, which was a bit of a strange beast, and for that hardware hacked model 40 that the Cambridge Scientific Center had, which was a one-off beast). But, yeah, for application mode code, you can (The privileged instructions aren't necessarily the same, but the non-privileged instructions mostly are upwards compatible.).