A single board bubble memory with perfect nonvolatility and an asynchronous parallel operation system using these memories have been developed. Through the use of a saturable coil and a capacitor, the voltage level of the bubble memory power source is maintained. Consequently the proper shut-down sequence can be observed, even in ease of power failures for either open or short circuits. The coil has a small core section to keep it saturated and to reduce its induction during normal operation. When a short circuit occurs, the coil loses saturation and prevents a discharge from the capacitor. Perfect nonvolatility of the bubble memory has been confirmed by 1000 successful power failure tests. In the extended memory, several boards operate asynchronously in parallel through a simple bus arbiter to increase the data transfer rate, Coincidence of the data stream during read and write operations is achieved by the periodic assignment of each memory board to the main memory for every word. This organization adds flexibility to the capacity and the data transfer rate of the bubble memory.