The legendary Seymour Cray was famed for being able to switch in a bootloader from memory.
Back in those days, all ops could do that. Admittedly, doing it on a CDC6600 like Seymour was using was a bit more involved, but I certainly could do it on a PDP-11 30 years ago (no…I don’t remember now). I have many acquaintances that still do it regularly on a PDP-8, PDP-11, IBM or DG today.
Now the folks who could front-panel the test routines from memory…that was impressive.
Reminds me of a blog post I made years ago about the ancient and obscure “dsw” Unix command: https://web.archive.org/web/20111104141518/http://dvlabs.tippingpoint.com/blog/2008/03/18/a-bit-of-history
Very interesting post. But:
Back in those days, all ops could do that. Admittedly, doing it on a CDC6600 like Seymour was using was a bit more involved, but I certainly could do it on a PDP-11 30 years ago (no…I don’t remember now). I have many acquaintances that still do it regularly on a PDP-8, PDP-11, IBM or DG today.
Now the folks who could front-panel the test routines from memory…that was impressive.
And
ddstands for Data Definition, the name of the analogous command on IBM mainframes.