Re: Add on serial port cards and boot prompt.

[Scrap Happy <Scrap%GMX.com@localhost>]

Hi Nat,

On 6/27/2012 9:28 AM, Nat Sloss wrote:

> I am considering upgrading my motherboard (from a Pentium 3 128M memory) and
> I've found that only some have on board serial port connectors (for the ones
> I've seen you only get one).

If you can visually inspect the board, look for an "unused" 10pin header
(2 rows of 5 pins sticking up out of the board) usually with one of the
corner pins clipped off.  This is often the second serial port (many
motherboards used a "combo" chip that implemented two serial ports
and they just omitted the extra DB9 for cost savings or to economize
on back panel space).  More often than not, these headers used a
common pinout and the DB9-with-attached-10-pin-ribbon-cable is
a pretty common thing to find.

You can often find the connector mounted to one of the filler plates
for the card cage/bus.  I.e., imagine a "card" that consists solely
of a connector with a cable dangling from it.  This facilitates
mounting the connector -- at the cost of a card slot.

> So I'm stuck to the possibility of an add on serial board (PCI or PCI-e).
>
> I am currently accessing my computer through a serial console enabled from
> boot.
>
> I am considering building the system without a video card as I'll mostly use
> network and serial access.
>
> So my question is will boot on the i386 or amd 64 support add on serial port
> cards?  Will I be able to access the boot menu as before?

I've played musical chairs with my machines so often that I can't
swear to the fact that my name server is currently configured that
way but it was, at one point.  I think I might have a 7" monitor
attached to it, currently (it's all tucked away under a dresser else
I would go check to be sure :< )

You'll have to build a custom kernel:

options CONSDEVNAME="\"com\"",CONADDR=0x???,CONSPEED=?????
options CONS_OVERRIDE

Note that you can also replace the bootstrap code to talk to the
serial port "earlier" in IPL.

> I've heard of some cards having a legacy mode does this mean that it will be
> on port 0x3F8?
>
> I'm hoping that someone on the mailing list has tried this.
>
> Thanks in advance,

Good luck!
--don