I believe those scenes were an amalgamation of Tim Paterson’s clean room implementation of DOS from the CP/M manuals [0] and Compaq’s IBM compatible BIOS implementation[1].

They are a some of my favorites, and are fun to watch.

[0] https://dfarq.homeip.net/did-microsoft-steal-dos-from-cpm/

[1] https://dfarq.homeip.net/first-compaq-computer/