A checkpointing page store for write-once optical disk

A model paging system is described for write-once optical disk. The paging system checkpoints pages on a nonerasable, failure-resistant medium as a side effect of virtual memory operation. Most pages are already checkpointed at any given time. It is practicable to checkpoint the global state periodically by forcing the write-out of pages that have been modified since their last checkpoint, together with the page tables. The proposed checkpointing algorithm was simulated to evaluate the performance of paging and checkpoint to write-once optical disk. There are plausible values for the operating parameters that make the overhead of checkpointing negligible compared to paging. The lifetime of 1-GB write-once optical disk media used for paging and checkpointing can range up to three months under plausible operating conditions