A method for rewriting data in a three-dimensional optical memory element created in glass with ultrashort light pulse includes creating a bit due to a photo-induced contrast in index of refraction inside the glass in three dimensions depending of the strength of a first ultrashort-pulse laser beam. User code may thus issue the sequence of instructions, then check the flag to determine whether it is executing on simulated hardware or physical hardware. The cover attachment member may be attached to the rail member in various different positions to accommodate variations in the cover dimensions. The lift sections are raised upwardly to carry the boat from the water and to another location over a land surface. The unstrained Ge-containing source can comprise a solid Ge-containing source, a gaseous Ge-containing source, or ions of Ge. The memory circuit includes a second field effect transistor which includes an oxide semiconductor layer where a channel is formed and in which a data signal is input to one of a source and a drain.