[TUHS] Bootstrapping UNIX - how was it done

[Peter Weinberger (温博格) via TUHS]

As I remember, the 11/70 was booted just as John describes. One keyed
in a boot loader at the console.

On Mon, Mar 23, 2026 at 3:11 AM John P. Linderman via TUHS
<tuhs at tuhs.org> wrote:
>
> >
> > >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