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>You can run lots of code from the 70's with little to no modification on a z series mainframe, because its visualized. Ok, I thought the main mechanism for ru

by jasode 12y ago

>You can run lots of code from the 70's with little to no modification on a z series mainframe, because its visualized. Ok, I thought the main mechanism for running old code was instruction-set-compatiblity-mode emulation and not full isolated virtualization. Could you copy an entire OS+app stack as a self-contained disk file from one mainframe to another? Regardless of the z series vm capabilities, I don't think people think of that as "mainframe time sharing" and that's what tripped me up.

KaiserPro 12y ago
yup, pretty much The best part about IBM mainframes was/is that you shouldn't need to worry about copying the OS to keep the App happy. The mainframe OS effectively provides a VM in a similar style to python or java. You tell it what version of machine its supposed to run on and it'll provide an environment with all the quirks. The article goes on to talk about uOS type systems, which are there to provide a Linuxy shim (with all the quirks) between the hypervisor and the App. (do you start to see where I'm going? :) )