I think what you are referring to is the "sub capacity" pricing model wherein a rolling average of resource consumption is used for billing. They've transitioned to newer models circa cloud technology, but it's mostly the same idea with more moving parts.
The advantage of this model from a business operations standpoint is that you don't have to think about a single piece of hardware related to the mainframe. IBM will come out automagically and fix issues for you when the mainframe phones home about a problem. A majority of the system architecture is designed on purpose to enable seamless servicing of the machine without impacting operations.
> IBM will come out automagically and fix issues for you when the mainframe phones home about a problem. A majority of the system architecture is designed on purpose to enable seamless servicing of the machine without impacting
I'd rather have a fault-tolerant distributed software system running on commodity hardware, that way there's a plurality of hardware and support vendors to choose from. No lock-in.
That's like toy drone company trying to compete with DARPA. Not even close.
These kinds of monsters run under critical environments such as airports, with AS400 or similar terminals being used by secretaries. These kind of workloads, reliability, security, testing, are no joke. At all. This is not your general purpose Unix machine.
> I'd rather have a fault-tolerant distributed software system running on commodity hardware, that way there's a plurality of hardware and support vendors to choose from. No lock-in.
But then you'd have to develop it yourself. IBM has been doing just that for 60 years (on the 360 and its descendants).
(Where you can save money buying Linux or Java accelerators to run things on for free