Thank you Ravi. Some use cases could probably be found in (portable) healthcare devices that don't need 99.998% of 24x365 availability. I don't think stripping down functionallity would be necessary since this would require development and maintenance of a "special Raspberry" version of IRIS. The licensing part would be another story ;-).  But because small computers like the Raspberry Pi (and Raspberry Zero) are so powerful today (and inexpensive) a lot of new applications can be thought of. If there are situations (I think mostly in the care/healthcare area) where FHIR and integration are needed in a small platform this certainly could be an option. I don't think however that for really critical applications, where health, lifes or welbeing can be dependant of this would be an advisable direction. And -from another perspective- we should take care not to desperately find a problem for this solution. Over all I'm already very happy with the opportunity to play around with IRIS and FHIR without big expenses. 

Hi Yankai, thank you. The InterSystems FHIR server as I wrote about is now running for 20 days without any interruption. It is -of course- not heavily used, only for my own testing purposes. A Raspberry Pi is IMHO not suitable for critical applications like airplane-control,  critical healthcare systems etc and I don't think InterSystems will support "IRIS on Raspberry" . But the combination of the Raspberry Pi and IRIS appears to me, based on my modest usage,  as to be pleasantly stable. Which is in line with my earlier experiences with Caché and Ensemble.

ubuntu@Ubuntu01:~$ uptime
 15:26:47 up 20 days,  3:19,  1 user,  load average: 0.02, 0.03, 0.00