Re: New-bus unit wiring via hints..

> From: Marcel Moolenaar <xcllnt_at_mac.com>
> Date: Sat, 27 Oct 2007 15:04:40 -0700
> 
> 
> On Oct 27, 2007, at 2:24 PM, Kevin Oberman wrote:
> 
> >> From: Marcel Moolenaar <xcllnt_at_mac.com>
> >> Date: Sat, 27 Oct 2007 13:57:25 -0700
> >>
> >>
> >> On Oct 27, 2007, at 12:40 PM, Kevin Oberman wrote:
> >>
> >>>> I'm not mandating anything. I'm merely pointing out how
> >>>> reality has changed and that it's important to adapt,
> >>>> adopt and improve...
> >>>
> >>> "Reality has changed"? Yes, it has, at least a bit, but not to the
> >>> point where we want to confuse serial ports.
> >>
> >> Are you saying that "we" should accept reality's change
> >> only for as far as it doesn't confuse "us" ???
> >
> > Just in case I don't understand the issue, feel free to correct me,  
> > but
> > it sounds like you are saying that there will not be a clear link
> > between the serial port (sio) number and the port marked '1' on most
> > systems.  If I am wrong about this, please tell me and I climb back
> > under my rock.
> 
> That is not what I'm saying. What I'm saying is:
> If the firmware tells the OS that the port marked
> "1" on the back corresponds to a UART that has a
> base I/O port address of 0x2e8, then who are we
> to disagree and demand that it should be 0x3f8?
> 
> You rightly point out that what it really boils
> down to is how devX maps to a port on the back or
> front of the machine. This mapping should not
> change gratuitously. Device wiring achieves that.

OK. I'm still not entirely comfortable with this, but you make an
excellent point here. I'd feel better about it if I had not encountered
so many systems with broken BIOS, though.

> Why not? You replace a mainboard. You really replaced the
> whole computer, because there's no concept of chassis
> port numbers in FreeBSD. All we know about the hardware
> is what is on the mainboard.
> 
> > The new system has, to the typical user's eyes, the same
> > configuration.
> 
> Yes. this means there's a gap between what the user sees
> (the chassis) and what FreeBSD sees (the mainboard). As
> long as the mainboard is designed for the chassis, that
> gap is mostly non-existent or insignificant and what the
> firmware tells the OS is what you see on the back (or
> front). Otherwise, all bets are off...
> 

Once again, this assumes competent firmware from the manufacturer, but
you are probably really right.

I guess it goes back to when you HAD to specify an address and IRQ for
every device (as well as where it tied to the system) in the old days
and I will concede that those days are past and that is a good thing.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman_at_es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751