Cisco Catalyst 8500 series NSO SSO dual route processor

[GIANRICO FICHERA]

Hello,
   I'm evaluating the use of the new Cisco edge 8500L device instead of the ASR1001 series.
I read that the system is able to run in software two different IOS processes, I imagine that the system has an linux hypervisor with different VM or something like docker and containers.
The documentation says: "This architecture allows for software redundancy opportunities that are not available on other platforms that run Cisco IOS software. Specifically, a standby IOS process can be available on the same Route Processor as the active IOS process. This standby IOS process can be switched to in the event of an IOS failure. On the Cisco 8500 Series Catalyst Edge Platform, the second IOS process can run only on the standby Route Processor."
The 8500 series has only one RP so I don't understand what "standby Route Processor" means. Is a "software" route processor"?
What real advantages we have with this configuration? I can imagine that one of the advantages is updating the operating system without losing continuity but the documentation talks about rebooting the system after an upgrade... So it is possible to have "no downtime software upgrades"? 

Thank you

[marce1000]

 - Checkout : https://www.cisco.com/c/en/us/products/collateral/routers/catalyst-8500-series-edge-platforms/intro-c8500l-edge-platform-wp.html , look at  paragraph : Control plane architecture , that may provide more insights w.r.t your questions.

 M.

[GIANRICO FICHERA]

The problem is that there is an overlap between the documentation of ASR1000 and that of 8500. Just to give another example you can read:

"The request platform software package command is part of the larger request platform command set being introduced on the Cisco Catalyst 8500 Series Edge Platforms" but the command exist in ASR1000.

Another example:
"The basic syntax of the command is request platform software package install rp rp-slot-number file file-URL , where rp-slot-number is the number of the RP slot" but the RP slot can be only 0 in C8500.

I think that the C8500 documentation is a work in progress and they are working on it right now to improve it.