On Jun 24, 9:46*pm, john B. wrote:
...
I actually met a bloke that had worked on computers where to boot you
had to enter a small "read that and do something about it" routine on
the front panel.

I'm a bloke who designed and built one. The manually entered bootstrap
loader was a 32 byte loop that read in a Teletype tape, downwards so
the final byte overwrote a jump destination to start the monitor
program, which was a very simple operating system that could load more
code from paper or magnetic tape.

IIRC the bootstrap loader began with a conditional jump to the monitor
that wasn't true at cold start. The paper tape boot program changed it
to JMP to skip the bootstrap loader at subsequent resets.

jsw