That makes almost no sense. S3 is a purely network based file delivery service over HTTP, and pre-dates EC2 by a significant amount of time.
A Xen supervisor needs a fair amount of memory for its own operations, plus it can buffer the physical disks in the machine as well as any network attached storage. If these servers were also hosting S3 in their "spare time" it would degrade performance, and expose the system to potential vulnerabilities.
A Xen supervisor needs a fair amount of memory for its own operations, plus it can buffer the physical disks in the machine as well as any network attached storage. If these servers were also hosting S3 in their "spare time" it would degrade performance, and expose the system to potential vulnerabilities.