DOOM was one of those games that relied on stretching the hardware to its limits to produce previously-unseen visual effects. The only thing that mattered was getting pixels on the screen as fast as possible.
Edit: no, of course there weren't any mutex primitives in DOS/4GW. It's a single-process single-thread bare metal environment. You have to realise that, in 1993 PC gaming, shared memory multithreading was simply not something that developers would ever encounter. It had no concievable advantages as you had only one CPU, not even a graphics accelerator. Games generally wouldn't multitask either; again, this predates consumer availability of Win32 and certainly is several years before DirectX.
DOOM was one of those games that relied on stretching the hardware to its limits to produce previously-unseen visual effects. The only thing that mattered was getting pixels on the screen as fast as possible.
Edit: no, of course there weren't any mutex primitives in DOS/4GW. It's a single-process single-thread bare metal environment. You have to realise that, in 1993 PC gaming, shared memory multithreading was simply not something that developers would ever encounter. It had no concievable advantages as you had only one CPU, not even a graphics accelerator. Games generally wouldn't multitask either; again, this predates consumer availability of Win32 and certainly is several years before DirectX.