Yes, a total classic.
I am totally impressed, I have been working with Z12/Z13  systems (from remote only) for a few years now, this talk is regularly devoured by me and my colleagues. Legend.
Despite from being as opposite from open source as you can get, I admire the elegant simplicity of z/OS. You literally hace got computing history at your finger tips. The first virtualized system went live in 1967, while The Beatles were just recording Sgt Pepper. It's the same year The Doors released their debut, as well as Pink Floyd, Jimi Hendrix.
When working on z/OS you are still working with very space limited consoles, you encounter punch card measurements kind of everywhere. They say that even today's z/OS is fully backwards compatible, you could still read and run ancient code from punch cards, all you need is a reader.
It's a completely different world, and I always say that a Z is kind of a whole data centre inside a cupboard. That implicitly tells you a lot about the complexity, but I think it's elegant and fascinating.
During a class we were told just one fully extended Z13 had enough power to run the entire internet.
I am constantly impressed by that presentation. Epic.

(So far I still need to encounter a real Z in the physical range, so ... that talk is just great.)