Huh, so someone actually built this? I was thinking about something similar the other day, in the form of a Windows 9x driver that would use that inaccessible RAM as a "page file".
I did a similar thing on my DOS PC. Lots of DOS software gets confused when there is more than 64MB of XMS/EMS free. So I just gave 64MB of the 128MB to smartdrv.
It's more RAM drive I ever had when using DOS for work back in the day.
Win95 complains about needing REAL mode compatibility for a RAM disk though. I wonder how much performance degradation is noticeable with a RAM disk though.
Yes certain software for Canadian made nuclear power plants, comes to mind. Was a post on the VCF forums about a job listing that required PDP-11 knowledge.
Apparently there is important stuff still running in emulated PDP-11s, almost double the age.