[TUHS] maybe off-topic: Unix on a microcontroller

[TUHS] maybe off-topic: Unix on a microcontroller

[arnold]

https://hackaday.com/2018/06/03/its-unix-on-a-microcontroller/

A neat hack, if nothing else. :-)

Arnold

Re: [TUHS] maybe off-topic: Unix on a microcontroller

[Lars Brinkhoff]

Arnold wrote:
> https://hackaday.com/2018/06/03/its-unix-on-a-microcontroller/

It says PDP-11 right in the article, so it must be on topic.

RetroBSD is a different take.  Instead of running a PDP-11 emulator on
the microcontroller, they ported 2.11BSD to run on the metal:

http://retrobsd.org/

Re: [TUHS] maybe off-topic: Unix on a microcontroller

[Warner Losh]

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On Fri, Jun 15, 2018 at 3:22 AM, Lars Brinkhoff <lars@nocrew.org> wrote:

> Arnold wrote:
> > https://hackaday.com/2018/06/03/its-unix-on-a-microcontroller/
>
> It says PDP-11 right in the article, so it must be on topic.
>
> RetroBSD is a different take.  Instead of running a PDP-11 emulator on
> the microcontroller, they ported 2.11BSD to run on the metal:
>
> http://retrobsd.org/


It looks like retrobsd hasn't been active in the last couple of years
though. A cool accomplishment, but with some caveats. All the network is in
userland, not the kernel, for example.

Warner

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Re: [TUHS] maybe off-topic: Unix on a microcontroller

[Tom Ivar Helbekkmo via TUHS]

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Warner Losh <imp@bsdimp.com> writes:

> It looks like retrobsd hasn't been active in the last couple of years
> though. A cool accomplishment, but with some caveats. All the network
> is in userland, not the kernel, for example.

Isn't 2.11BSD networking technically in userland?  I forget.  Johnny?

-tih
-- 
Most people who graduate with CS degrees don't understand the significance
of Lisp.  Lisp is the most important idea in computer science.  --Alan Kay

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Re: [TUHS] maybe off-topic: Unix on a microcontroller

[Warner Losh]

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On Fri, Jun 15, 2018 at 1:09 PM, Tom Ivar Helbekkmo <tih@hamartun.priv.no>
wrote:

> Warner Losh <imp@bsdimp.com> writes:
>
> > It looks like retrobsd hasn't been active in the last couple of years
> > though. A cool accomplishment, but with some caveats. All the network
> > is in userland, not the kernel, for example.
>
> Isn't 2.11BSD networking technically in userland?  I forget.  Johnny?
>

It looks to be integrated into the kernel.

Warner

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Re: [TUHS] maybe off-topic: Unix on a microcontroller

[Johnny Billquist]

On 2018-06-16 04:00, Tom Ivar Helbekkmo<tih@hamartun.priv.no> wrote:
> Warner Losh<imp@bsdimp.com>  writes:
> 
>> It looks like retrobsd hasn't been active in the last couple of years
>> though. A cool accomplishment, but with some caveats. All the network
>> is in userland, not the kernel, for example.
> Isn't 2.11BSD networking technically in userland?  I forget.  Johnny?

No, networking in 2.11BSD is not in userland. But it's not a part of 
/unix either. It's a separate image (/netnix) that gets loaded at boot 
time, but it's run in the context of the kernel.

I'd have to go and check this if anyone wants details. It's been quite a 
while since I was fooling around inside there. Or maybe someone else 
remembers more details on how it integrates.

   Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt@softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

Re: [TUHS] maybe off-topic: Unix on a microcontroller

[Noel Chiappa]

    > From: Johnny Billquist

    > It's a separate image (/netnix) that gets loaded at boot time, but it's
    > run in the context of the kernel.

ISTR reading that it runs in Supervisor mode (no doubt so it could use the
Supervisor mode virtual address space, and not have to go crazy with overlays
in the Kernet space).

Never looked at the code, though.

	Noel

Re: [TUHS] maybe off-topic: Unix on a microcontroller

[Tom Ivar Helbekkmo via TUHS]

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Noel Chiappa <jnc@mercury.lcs.mit.edu> writes:

> ISTR reading that it runs in Supervisor mode (no doubt so it could use the
> Supervisor mode virtual address space, and not have to go crazy with overlays
> in the Kernet space).

Indeed.  From "Installing and Operating 2.11BSD on the PDP-11":

    The networking in 2.11BSD runs in supervisor mode, separate from
    the mainstream kernel.  There is room without overlaying to hold
    both a SL/IP and ethernet driver.  This is a major win, as it
    allows the networking to maintain its mbufs in normal data
    space, among other things.

-tih
-- 
Most people who graduate with CS degrees don't understand the significance
of Lisp.  Lisp is the most important idea in computer science.  --Alan Kay

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Re: [TUHS] maybe off-topic: Unix on a microcontroller

[Johnny Billquist]

On 2018-06-17 04:00, jnc@mercury.lcs.mit.edu  (Noel Chiappa) wrote:
>      > From: Johnny Billquist
> 
>      > It's a separate image (/netnix) that gets loaded at boot time, but it's
>      > run in the context of the kernel.
> 
> ISTR reading that it runs in Supervisor mode (no doubt so it could use the
> Supervisor mode virtual address space, and not have to go crazy with overlays
> in the Kernet space).

Yes. That rings a bell now that you mention it. Pretty sure you are correct.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt@softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol