The labor cost of requesting a VM clone via the MyPHRMachines portal is negligible. Other labor costs relate to (1)uploading application executables to MyPHRMachines, and (2) configuring them in an instance of the new VM image. The first cost is unavoidable since by definition it becomes relevant any time a software vendor wants to deploy software to a cloud-based system. About the second cost, any IaaSbased approach would provide the same level of flexibility as MyPHRMachines. However, in more general IaaS platforms (e.g. Amazon EC2), VM images would have to be cloned explicitly for each end-user. Also, end-users would be able to change the VM images, introducing huge maintenance costs. Instead, the MyPHRMachines approach of using stateless VM sessions (i.e., sessions that do not affect the VM image
involved) avoids that cost problem by design.