The bit that piqued my interest was the fact that the saved system is defined as Class A (unrestricted) because there are no shared R/W areas t o otherwise pose security issues - and can therefore be IPLed by anybody - NAMESAVE not needed. Each user effectively gets their own, 'Group of one' .
It is also worth remembering that it's pretty simple to build multiple GC S's - if you had a requirement for a sandpit you could easily build a, 'GCSON E' NSS alongside the, 'production' multi-user, 'GCS' NSS. Of course, if you try to run the whole VTAM / RSCS bunch in there it's going to get <ahem> crowded, and you won't be giving CP's scheduler much chance to work his stuff so it might become something of a bottleneck ... I still to this day think that it's a shame that GCS was never allowed to reach its full potential - when I'm in a, 'conspiracy theory' mood I thin k maybe the MVS camp was afraid of the possible competition and squashed it . I also yearn to see, 'real IUCV' one day - although I guess that need has now actually been fulfilled in other more, 'open' ways ...