The CDC6600 was the most powerful computer of its time, designed by Seymour Cray who had left IBM.
He later left CDC to set up his own company.
The components were suspended between two cards, maintenance within the unit was impossible,
the whole unit would be replaced.
This card was from the University of London Computing Centre machine. Part of the computer time on their CDC was allocated to large projects at other universities, including Nottingham.
The ULCC centre was run at that time by Neil Spoonley.