[4ad]

It has been assigned to Doom for a very long time. A decade at least (maybe decades?).

[jvolkman]

The associated email address, [e-mail], was for Dave Taylor who worked at id from 93-96. So about 3 decades.

[solardev]

3 decades later, they've been bought up by ZeniMax and then Activision Blizzard. I guess Hell has frozen over.

[sgerenser]

Forgot "and then Microsoft."

[imwillofficial]

Decades at least