[TUHS] Bootstrapping UNIX - how was it done

[John R Levine via TUHS]

On Mon, 23 Mar 2026, ron minnich wrote:
> I believe on the -8 it was called the RIM loader?

That was what DEC provided but there was a much shorter version that 
needed you to hit the start key twice, as a kludgy way to wait for the 
paper tape reader.  But that was definitely not Unix.

R's,
John


>
> On Mon, Mar 23, 2026 at 10:37 AM Paul Winalski via TUHS <tuhs at tuhs.org>
> wrote:
>
>> On Mon, Mar 23, 2026 at 12:20 PM John Levine via TUHS <tuhs at tuhs.org>
>> wrote:
>>
>>> It appears that Peter Weinberger (温�  � �) via TUHS <pjw at google.com>
>> said:
>>>> As I remember, the 11/70 was booted just as John describes. One keyed
>>>> in a boot loader at the console.
>>>
>>> I'm pretty sure our PDP-11 at Yale had a boot ROM, so you just set
>>> the starting address from the switches and started it.
>>>
>>> Before that I toggled boot loaders into PDP-8's and I don't miss it.
>>>
>>> The 11/70 most certainly had a boot ROM--the M9312.  Perhaps the version
>> of Unix in question wasn't compatible with the M9312 bootstrap loader, or
>> they just preferred their own bootstrap loader to the M9312?  Or maybe they
>> didn't have a M9312 installed.