The term Blue Screen of Death originated during development of the OS/2 operating system at Lattice Inc, the makers of an early Windows and OS/2 compiler.[citation needed] Developers encountered the Stop screen when bugs in the operating system's software (typically null pointers) slipped through the net during beta testing. In feedback to IBM, a company known informally as 'Big Blue', the developers humorously described the Stop screen as the 'Blue Screen of Death' in consequence of its colour, of the association of that colour with IBM, and of the finality of the error (which caused the computer to hang without any possibility of recovery, compelling a manual restart)