Whilst the idea of Software as a Service (SaaS) is increasingly mainstream Hardware as a Service (HaaS) is still a new concept. An example of such a service is Amazon's Elastic Computer Cloud (EC2) which was announced in the summer of 2006. EC2 is a computing service based on a Xen hypervisor structure. It allows a developer to create Linux based virtual machines, either from scratch or using pre-built image files. Then, using either a web services API or a script-wrapper around that API, you can quickly deploy to any number of virtual machines.
The virtual machine structure allows Amazon to offer a variety of VM sizes up to the physical limits of the hardware. So in addition to the default small instance (1.7 GB of memory, 1 1.0-1.2 GHz 2007 Opteron/Xeon processor, 160 GB of instance storage, 32-bit platform) Amazon now offers large (7.5 GB of memory, 4 processors spec as before, 850 GB of instance storage, 64-bit platform) and extra large (15 GB of memory, 8 processors spec as before, 1690 GB of instance storage, 64-bit platform) instances.
