IRIX Doom was originally based on the unreleased MS-DOS version 1.5, though later updates were based on versions 1.6 and 1.8.
IRIX ĭoom was ported to IRIX during the summer of 1994 by Dave D. A successful version was demoed in 1994 running in an OS/2 PM window. OS/2 ĭoom was ported to OS/2 by an independent contractor, Jim Thomas, who was hired by IBM to port it and SimCity. The version running on NeXT is programmed by John Carmack, John Romero, and Dave Taylor. With NeXT-Step based on i486 architecture, it ran smoothly under all conditions up to screen sizes of 400% with newer hardware. This version is sluggish on anything below an 040 NeXTstation/cube (though it runs smoother with a higher amount of memory), and is missing sound, which was added on the PC side. This was the version that the MS-DOS product emerged from, since, at the time, id Software was using a NeXTcube for its graphic-engine development.
