Abstract: A communication coupling technique is disclosed that uses optical signals separators that may be formed using optical wave guides, hollow tubes, or any material that separates signals emitted from one source from signals emitted from other sources.

Abstract: A signal synchronizer according to embodiments herein uses a delay register that receives a feedback signal. The delay register has many delay circuits, each of which are adapted to delay the feedback signal at different time intervals. A storage register made up of many binary storage devices receives a reference signal. Each storage device is adapted to store a feedback signal state of a corresponding delay circuit. As the feedback signal is delayed the additional time intervals by the successive delay circuits, it will change states (either from high to low, or low to high) and the different storage devices simultaneously store the feedback signal states of each of the delay circuits, as controlled by the reference signal. The change in feedback signal state between adjacent storage devices records a synchronization separation between the feedback signal and the reference signal. A control device synchronizes the feedback signal based on the synchronization separation as recorded by the storage register.

Abstract: Incremental single and multiprocess checkpointing and restoration is described, which is transparent in that the application program need not be modified, re-compiled, or re-linked to gain the benefits of the invention. The processes subject to checkpointing can be either single or multi-threaded. The method includes incremental page-boundary checkpointing, as well as storage checkpointing of data files associated with applications to ensure correct restoration without the need to restore files for other application programs. Incremental and full checkpoints are asynchronously merged to ensure proper operation while reducing checkpointing delay. By way of example a user-level programming library is described for loading into the address space of the application in conjunction with a loadable kernel module (LKM) or device driver used to capture and restore process state on behalf of the application. These techniques are particularly well suited for use with high-availability (HA) protection programming.