In 1978 Linotron 606 phototypesetters had an intermittent problem that sometimes a small section of text would appear as if the letters had been chopped up in a

In 1978 Linotron 606 phototypesetters had an intermittent problem that sometimes a small section of text would appear as if the letters had been chopped up in a blender. Nobody could figure it out for about 6 months. Turned out to be a bug in the routine that handled disk errors when the character vector data was being downloaded from disk. The character buffer that contained the character vectors had a blank scan line used for white on black reverse video background placed at the beginning of the buffer. The routine that handled disk errors just refilled the buffer from the beginning without the blank and so all the addresses of the start of each of the characters was off. My favorite actual hack came a couple of years later at Bell Labs Naperville where I made the curses library terminal version of Space Invaders play PacMan instead.