Apple is betting to undertake a path in which it does not exactly have a solid experience. For iCloud to work properly it depends on a lot of technology working behind it and for this new Apple service to work smoothly and without errors it has saved its back with (paradoxically) Windows Azure and Amazon S3 . These are perhaps two of the most widely used platforms in cloud computing today.
Windows Azure is a CDN (Content Delivery Network) presented by Microsoft in 2008, based on Windows Server 2008, which will apparently be in charge of distributing the content sent and received through iCloud. Some tests also show that Amazon S3 is also used when serving certain content. If Windows Azure, with its Windows 2008 server gives a bombproof system stability (it really is) Amazon S3 can be a perfect complement to store files and backups .
Assembling the infrastructure needed for the landing of iCloud goes beyond building three data centers. Yes, it is important, but with 200 million iOS devices on the market, many people will have access to it a priori. Only time will tell us if this is really the beginning until the data centers are fully operational, or if it is a firm decision taken by Apple , being the one that will simply store the content using Windows and Amazon servers to serve it.