David,
Answer "postgres" would suffice. I have fairly decent idea of what happens below that (you are right system utility - Memory Manager is what marshaling data back and forth to RAM, abstracting absolute addresses from application along the way, and once in RAM, security kernel of the system protects data, terminating any process which tries to obtain data from another process - provided data were not shared to begin with).
Thanks a lot for your consultation guys.
Oleg
