Jim Wilkins wrote:
On Jun 24, 9:46 pm, john 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


The Okuma OSP-2000 cnc control loaded with boot strap loader loop. You
first have to manually set in about 21 bytes of code using switches to
set up the computer to run the bootstrap from a short punch tape. Once
you load the bootstrap the actual executive system tapes can be loaded.
These machines used two 8K bubble memory boards. The newer options
went with a cmos memory.

John