I was thinking about mini computers. DEC, Data General Nova, and others. The ones I used required the user to enter a boot loader because the pre IC ROM memory was very expensive.
Just for fun
The IBM 1620 introduced in 1959 required the operator to type in a bootstrap from the front console. I used one at NDSU in mid/late 70's. The machine was purchased by the EE department in 1961, it was the first computer in the state. By the time I got my hands on it the hard disk leaked hydraulic oil and we had learned how to reset the red emergency stop switch without calling IBM.
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