Abstract: Atomic write operations for storage devices are implemented by maintaining the data that would be overwritten in the cache until the write operation completes. After the write operation completes, including generating any related metadata, a checkpoint is created. After the checkpoint is created, the old data is discarded and the new data becomes the current data for the affected storage locations. If an interruption occurs prior to the creation of the checkpoint, the old data is recovered and any new is discarded. If an interruption occurs after the creation of the checkpoint, any remaining old data is discarded and the new data becomes the current data. Write logs that indicate the locations affected by in progress write operation are used in some implementations. If neither all of the new data nor all of the old data is recoverable, a predetermined pattern can be written into the affected locations.

Abstract: Atomic write operations for storage devices are implemented by maintaining the data that would be overwritten in the cache until the write operation completes. After the write operation completes, including generating any related metadata, a checkpoint is created. After the checkpoint is created, the old data is discarded and the new data becomes the current data for the affected storage locations. If an interruption occurs prior to the creation of the checkpoint, the old data is recovered and any new is discarded. If an interruption occurs after the creation of the checkpoint, any remaining old data is discarded and the new data becomes the current data. Write logs that indicate the locations affected by in progress write operation are used in some implementations. If neither all of the new data nor all of the old data is recoverable, a predetermined pattern can be written into the affected locations.

Abstract: The present invention relates to a measuring device for measuring the relative-correctable difference in length of a person's legs in order to determine the amount of elevation required in the construction of an orthopedic shoe to compensate for such difference. The measuring device includes a base plate of predetermined thickness and a sole plate of predetermined thickness, the sole plate having a plan configuration similar to the base plate. Means are provided for preventing relative movement of the sole plate and the base plate, and means for securing the base plate and the sole plate to the foot of the associated person is provided whereby such person can stand and walk on the measuring device. Additional measuring plates of predetermined thickness are provided for increasing the elevation of the measuring device in predetermined increments whereby the correctable difference in elevation of the associated person's leg can be determined.