Services
Basic principles:
-  Open architecture 
-  Distinguish products vs protocols 
-  Provision the service independently from the server (e.g. mail.company.gr)
-  Insist on locating the service in the computing centre
	
	- Protected power
- Cooling and humidity control
- Fire suppression
- Physical security
- Network capacity
 
-  Can have multiple servers for the same service 
-  Need mechanism for service monitoring 
-  Expand or organise into one server for each service