On Mon, 12 Aug 2024 01:16:41 -0700,"Erik E. Fair" <fair-tuhs@netbsd.org> wrote:

The main campus computer center was in the basement, but they charged by the CPU/second, so only classes used those systems - in my day (1980-1983), the computer center had a CDC 6400 and six or seven DEC PDP-11/70s.

The CDC 6400 finally went away in September 1982:

September 3rd, 1982
Memo to: Computing Affairs Staff
From: M.Stuart Lynn, Director
Subject: CDC 6400 Departure

The CDC 6400 is no more. ...

https://caltss.computerhistory.org/archive/820903-cdc-6400-departure-msl.pdf