[TUHS] Clever code (was Re: Re: Stdin Redirect in Cu History/Alternatives?

[Andrew Warkentin]

On 12/13/22, Larry McVoy <lm at mcvoy.com> wrote:
>
> Have you talked to Andy and confirmed that?  I'd be quite surprised if
> he hadn't played with QNX but who knows.  I wouldn't assume he hadn't.
>

I haven't actually talked to him about it. He definitely is aware of
QNX since he's mentioned it on a few occasions, but I'm not sure if he
was aware of it when he wrote the first version of Minix.

Personally I don't see a lot of resemblance between the two, besides
both being single-personality Unix-like microkernel OSes with
lightweight IPC. Minix is more akin to a "serverized" conventional
Unix, whereas QNX seems to embrace its microkernel-ness more fully
with its focus on extensibility and its fairly tight integration of
IPC transport layer and filesystem. There may have been a little bit
of influence, but it's not all that obvious to me.

The pre-3.x versions seem especially un-QNX-like with their more or
less closed set of servers. Even in 3.x, the kernel still seems to
have quite a bit of knowledge about what servers are present and what
messages they accept. QNX does colocate the process server in the
kernel, but it makes very few assumptions about user-mode servers.

>
> And forgive me for asking, do you have some axe to grind against QNX
> or something?
>

Quite the opposite, hence why I'm writing my own OS with a similar architecture.

>
> To me, it's not that surprising that the rest of the world didn't copy
> QNX because the rest of the world was either a mono-kernel or it was
> Mach.  Don't get me started on Mach, it has defenders but I absolutely
> hate it.  Mach is more of a distributed research OS that advertised
> itself as a microkernel.  There is _nothing_ micro about Mach.  It's
> a big bloated mess.
>

Yes, I agree 100% that Mach is a complete and utter failure as a
microkernel, and seems to have almost single-handedly destroyed the
reputation of microkernels. I don't get why everyone was so focused on
Mach-like kernels when there was a better alternative that had been
around in some form for almost a decade before Mach (QNX wasn't the
first of its kind; it seems to have had pretty significant influence
from Thoth).