Abstract: A method and apparatus of performing fault tolerance in a fault tolerant computer system comprising: a primary node having a primary node processor; a secondary node having a secondary node processor, each node further comprising a respective memory; a respective checkpoint shim; each of the primary and secondary node further comprising: a respective non-virtual operating system (OS), the non-virtual OS comprising a respective; network driver; storage driver; and checkpoint engine; the method comprising the steps of: acting upon a request from a client by the respective OS of the primary and the secondary node, comparing the result obtained by the OS of the primary node and the secondary node by the network driver of the primary node for similarity, and if the comparison of indicates similarity less than a predetermined amount, the primary node network driver informs the primary node checkpoint engine to begin a checkpoint process.

Abstract: The disclosure relates to a method of checkpointing. The method may include determining, by the primary computer, when to initiate a checkpoint point operation; dividing, at the primary computer, checkpoint data into two or more groups, wherein each group includes one or more pages of memory; transmitting a first group to the secondary computer; upon receiving, by the secondary computer, the first group, correlating memory pages in the first group with pages in memory on the secondary computer; determining, at the secondary computer, which bytes of memory pages of the first group differ from the correlated pages stored in memory in the secondary computer; and applying data from the first group by swapping differences between the memory pages of the first group and the correlated memory pages stored in the secondary computer. Where at least some of these multiple operations are performed in parallel during a subset of the overall checkpoint operation.

Abstract: The disclosure relates to a method of checkpointing. The method may include determining, by the primary computer, when to initiate a checkpoint point operation; dividing, at the primary computer, checkpoint data into two or more groups, wherein each group includes one or more pages of memory; transmitting a first group to the secondary computer; upon receiving, by the secondary computer, the first group, correlating memory pages in the first group with pages in memory on the secondary computer; determining, at the secondary computer, which bytes of memory pages of the first group differ from the correlated pages stored in memory in the secondary computer; and applying data from the first group by swapping differences between the memory pages of the first group and the correlated memory pages stored in the secondary computer. Where at least some of these multiple operations are performed in parallel during a subset of the overall checkpoint operation.

Abstract: A method and apparatus of performing fault tolerance in a fault tolerant computer system comprising: a primary node having a primary node processor; a secondary node having a secondary node processor, each node further comprising a respective memory; a respective checkpoint shim; each of the primary and secondary node further comprising: a respective non-virtual operating system (OS), the non-virtual OS comprising a respective; network driver; storage driver; and checkpoint engine; the method comprising the steps of: acting upon a request from a client by the respective OS of the primary and the secondary node, comparing the result obtained by the OS of the primary node and the secondary node by the network driver of the primary node for similarity, and if the comparison of indicates similarity less than a predetermined amount, the primary node network driver informs the primary node checkpoint engine to begin a checkpoint process.