Creating permanent storage on the fly within existing buffers

A circular buffer having an active cache window can be configured to temporarily allocate one or more locations in the active cache as permanent memory locations to eliminate the possibility of overwriting the contents of the permanent memory locations. The cache window can be a subset of the entire circular buffer. If contents within the cache window are identified as persistent data, the locations corresponding to the persistent data can be identified as permanent memory locations. The position of the cache within the circular buffer can be frozen based on the permanent memory locations. A write mask can be used to maintain the contents of the permanent memory locations, while the remainder of the cache is configured as a temporary circular buffer. Operation of the cache returns to the entire circular buffer once the contents of the permanent memory locations no longer need to be maintained.