Black and Wiliam (1998a) also noted that for assessment to function formatively, the feedback information had to be used, and thus the differential treatments that are incorporated in response to the feedback are at the heart of effective learning.
A hypervisor is a unique type of software that allows a computer to run more than one operating system (OS). Through a process known as virtualization, the software tricks each OS into thinking it has exclusive access to a particular set of hardware.
However, the hypervisor is actually controlling the host processor and resources, allocating what is needed to each operating system in turn and making sure that the guest operating systems (called virtual machines) cannot disrupt each other. Utilizing snapshots to solve VM management headaches.