Recoverable virtual memory through the multi-view memory computer system

Recoverable virtual memory (RVM) is very useful for applications that require fault tolerance for persistent data structures. Updates to a recoverable region of memory are recorded so that recovery in case of faults is possible. Multi-view virtual memory (MVM) provides recoverability for a memory region by defining a view, consisting of access units, on that region. Finite state machines (FSMs) control access to the units of the view. The FSM states are defined to trap on the first,write to an access unit in order to save the before-image or to simply change the state of the unit so that an after-image can be recorded at a commit point. The recoverability provided by the MVM approach is compared to the hardware approach of Logged-RVM and to the software approach of Light-weight-RVM. The comparison is made qualitatively in terms of the interface and functionality, and also quantitatively by examining the delays using simple back of the envelope calculations.