 That sound was once the sound of hope and fear. Hope that whatever you'd saved was still on there. Fear that it wasn't, or worse, that it was, but it was corrupted, so your important document was now mostly ampersands. But it was also the sound of the future, courtesy of the data storage device of the future, a miraculous flat square known as the floppy disk. Of course, the floppy disk was only the future in the fairly distant past. By the 21st century, it had been replaced by less noisy, more efficient storage devices.