Langerhans Cell Histiocytosis with Characteristic Skin Involvement

Where the same data is stored for an extended period of time, the possibility exists of unwanted burning in of the data which would allow undesired recovery of erased data even after it has been over-written or the memory has been powered down. The memory contents are therefore periodically rewritten in the inverse of their former state, either to the same location in which they were previously stored, or elsewhere. Inversion may be performed in an invert cycle during which address decoders driven by a high speed oscillator read each cell and write back its contents inverted. On completion of a cycle, a latch may indicate whether the stored data is in a true or complement form. The latch may control programmable invertors so that cells are always read or written correctly, regardless of whether data happens to be in true or complement form.