OPERATING SYSTEM & DATABASE

I have on question ..In an Data Warehousing Environment .. How OPERATING SYSTEM & DATABASE are Interrelated in Designing ,Organisation and architecture ? can u anybody Please explain ..since the Warehouse is very big do we need to reconstruct the OS?

I'm not sure what you are asking - the relationship between a DB and an OS doesn't change because the DB happens to be a data warehouse. Your choice of OS is obviously limited to that/those supported by your choice of DB - if that's what you are asking?
If you are talking about how to spec. your environment in terms of hardware, memory, cpu, etc. then this Dimensional Modelling forum is probably not the place to be asking those sorts of questions