[TUHS] Bootstrapping UNIX - how was it done

[John P. Linderman via TUHS]

>
> >How was UNIX bootstrapped in the early days?
>
> When I started at the Labs in 1973, what eventually morphed into the
Programmer's Workbench UNIX ran a PDP45 in Piscataway, NJ. UNIX was
sufficiently flakey at that time that they liked to reboot the system each
day to clean up corruption in the file system. Someone noticed that I
arrived before 6 am every morning, when a reboot would go unnoticed by most
people. So I was taught how to halt the system, set a bunch of keys on the
front of the 45, and hit start. I'm guessing that the keys simply directed
the 45 to read a boot block from some device, and execute the instructions
in that block, where the real software bootstrapping began. I'm sure others
in this group can supply the correct details. I was not then, and still am
not now, a hardware person, but I remain an early riser. -- jpl