You are right to be skeptical. Unfortunately I could not find the "Handbuch für Datenverarbeitung" mentioned in the Stack Exchange post. Amazon lists it with IS

You are right to be skeptical. Unfortunately I could not find the "Handbuch für Datenverarbeitung" mentioned in the Stack Exchange post. Amazon lists it with ISBN 3927892009 but it is not available unsurprisingly. Neither libgen nor archive.org seem to have it either. Apart from several humorous mentions over the decades I found one serious reference in an exam text from 1997 [1]. [1] https://www.telle-online.de/fernuni/ruf/klausur/1704-97.html#:~:text=Entwerfen%2520Sie%2520eine%2520Einheit%2520f%C3%BCr,Kellerstapelspeicher%2529%2520%C3%BCberwacht https://www.telle-online.de/fernuni/ruf/klausur/1704-97.html...