I worked for NCR, and for 15 of my 34 years there I worked on these. 64-256K of memory. 2 FIVE MEG 20" platter, drives stacked in the cabinet. Head crashes involved many parts, an O scope and lotsa time.
THE CORE MEMORY: NCR Computers of the 20th Century
THE CORE MEMORY: NCR Computers of the 20th Century