Patent ID: 8381032

Claim:
A computer system configured to run a hypervisor operable to enable the state of one or more guest operating systems to be checkpointed, comprising: a memory-manage subsystem configured to maintain and use a temporary-read-only bit in tables used to convert pseudo-physical addresses of a hypervisor's guest operating system (OS) to physical addresses, and to use the temporary read-only bit in conjunction with another read-only bit to trigger a trap by which normal read-only page violations and violations for checkpointing are distinguishable by the hypervisor; a device-emulator subsystem configured to maintain input/output (I/O) read- and write-buffers in the hypervisor's virtual space, whose contents are preserved until the guest OS is checkpointed following completion of the I/O operation; and a rollback and recovery subsystem configured to periodically checkpoint the state of each guest OS of the hypervisor.