auzisem si eu la un moment dat ca cloudul apple ar rula pe windows azure… who knows 
din cate stiu, server farmul apple din carolina de nord are in dotare unix, linux, mac os x samd
One of Apple’s job postings for “iCloud Senior Unix Systems Engineer” gives some hints:
Apple’s iCloud service is an exciting, fast paced, ever growing and changing environment supporting millions of customers. The Internet Services Systems Engineering team is responsible for installation, configuration, troubleshooting, tooling automation and maintenance of the infrastructure related to this service.
- Minimum 5-7 years in UNIX systems administration in a large environment (1000+ servers).
- Background in Linux, OS X/BSD, Solaris, and networking
- Familiar and comfortable with the following: Apache, java, tomcat, dtrace, network analysis tools
- Jumpstart, Kickstart, DHCP, DNS, Configuration management, monitoring tools (ie: Nagios, big brother, etc)
Preferred Experience:
- RHEL 5 & 6, Solaris 10, OS X
Based on this post we can assume that Apple is using a mix of Linux and Solaris in production.
http://www.quora.com/Apple-Inc-2/What-OS-used-on-the-servers-in-Apples-North-Carolina-Data-Center
