Re: need a bit of early boot help

Den 2025-11-11 kl. 11:14, skrev Johnny Billquist:
> On 2025-11-11 06:00, Mouse wrote:
>>> NetBSD 1.6.1 [...] stops in a suspicious place: Right after printing
>>> "root file system type: ffs", on the next line, it prints an 'S' and
>>> hangs.  [simh indicates this] is the first character of this date
>>> stamp:
>>
>>> Sun Nov  9 22:05:50 GMT 2003
>>
>> [a second mail]
>>
>>> After sending that last email I went back to the console.  It had
>>> been sitting there for maybe ten minutes.  Suddenly it sprang to
>>> life; the date stamp never finished printing (at least not that I
>>> could see, but the console is only running at 1200 baud) but it
>>> printed the 'B' that starts the "Building databases..." line. It
>>> printed a few more lines after that and has now been hung again for
>>> several minutes.  I'm waiting to see if it starts up again.
>>
>> It printed a few more lines in full, or the first character of each?
>> If the former, were they printed at full normal 1200 baud, or did each
>> character take a long time to print?  See below for the relevance.
>>
>> I can hardly claim any particular insight into the 11/780 in
>> particular.  But it does occur to me that everything
>> before-and-including "root file system type: ffs" is printed from
>> within the kernel, but that timestamp is printed by userland.
>>
>> That may not be the relevant thing, though.  I don't know 1.6.1 in
>> enough detail, but perhaps kernel output is polled but userland is
>> interrupt-driven?  Maybe something is wrong with TXCS-driven
>> interrupts?
>
> That would be the case, yes. Unless I remember wrong.
> Since output from the kernel works, we can at least say that there is 
> nothing wrong with the serial port as such. And the booting process 
> went fine.
>
> And VMS also hangs after printing a banner... Which would suggest that 
> there is something funny either with the printing on the console, but 
> which is interrupt related, or something else is getting the machine 
> stuck at an elevated privilege mode, preventing interrupts from being 
> processed.
>
> I would actually probably suspect something else isn't completing, and 
> the processor is stuck at some elevated prio. The console is probably 
> working just fine, including when interrupt driven. But something else 
> is not.
>
> I assume we're talking about a real machine here. So it has actual 
> Unibus. Simple suggestions would be to remove everything not 
> absolutely required to get the machine running, and really make sure 
> you have bus grants in all Unibus slots not having a card in it. Also, 
> make sure the NPR jumper is in place. This one can be a bit tricky, 
> since it's actually a wire on the back side of the backplane, which 
> might have been cut. There a double height bus grant cards that also 
> covers the NPR signal, but the small square ones do not.
>
> And if the Unibus isn't properly configured, you can probably get 
> things hung/stuck for some time.
It's a 780, Unibus is not involved here at all :-)
The PDP11 is connected directly to the backplane (SBI).

-- R