[TUHS] Re: Why is it always "fast boot" in 2.11BSD?

[Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org>]

On Thu, May 26, 2022 at 01:41:29PM +0200, Matthias Bruestle wrote:
> I have noticed, that 2.11BSD is in all cases where I looked set
> to "fast boot", which AFAIK means no fsck of at least /. I found
> nobody talking about this or providing information about how to
> change it to "slow boot" with a proper check, which is now normal.
> 
> Is there a reason why it is not possible to deactivate fast boot?
> Or is it just that nobody bothered to do it?

Interesting. When I played with 2.11BSD a few years ago I found that it
only did a "fast" boot if rebooted with "shutdown -rf". A cold boot
would always drop into single user and allow running fsck manually.

IIRC /boot or even one of the earlier bootstrap stages would check a
certain memory location for certain values, which the kernel(?) would
place there in the reboot syscall. As I wanted to always force a fast
boot, I had this in my simh.ini to force a fast boot:

d 157772 177777
d 157774 002400
d 157776 000000

If you're using a simulator I wouldn't be suprised if it does that
automatically nowadays, of perhaps 2.11BSD was patched a while back to
reverse that behaviour.

I don't remember what these values do, though. And you want to do the
opposite anyway. But perhaps this helps you find out more. 


Hans


-- 
%SYSTEM-F-ANARCHISM, The operating system has been overthrown