Re: LILO and serial speeds over 9600

David Weinehall
2001-02-12T23:40:23Z

On Mon, Feb 12, 2001 at 03:17:04PM -0800, Ivan Passos wrote:
>
> On Mon, 12 Feb 2001, Scott Laird wrote:
> >
> > On 12 Feb 2001, H. Peter Anvin wrote:
> > >
> > > Just checked my own code, and SYSLINUX does indeed support 115200 (I
> > > changed this to be a 32-bit register ages ago, apparently.) Still
> > > doesn't answer the question "why"... all I think you do is increase
> > > the risk for FIFO overrun and lost characters (flow control on a boot
> > > loader console is vestigial at the best.)
> >
> > It's simple -- we want the kernel to have its serial console running at
> > 115200, and we don't want to have to change speeds to talk to the
> > bootloader.
>
> Exactly.
>
> Then HPA may ask: but why do you want to run the serial console at
> 115200?? The answer is simple: because we can (or more precisely, because
> the HW can ;).
>
> If the hardware is supposed to support 115.2Kbps, why can't / shouldn't
> we use it?? Remember, this is not a modem connection, there is no
> compression involved, both sides are running 115.2Kbps, so there should
> NOT be a risk for FIFO overruns (unless you have buggy hardware). And in
> this case, you can then decrease your baud rate. But at least you have the
> _option_! :)
>
>
> > Some boot processes, particularaly fsck, can be *REALLY*
> > verbose on screwed up systems. I've seen systems take hours to run fsck,
> > even on small filesystems, simply because they were blocking on a 9600 bps
> > console.
>
> This is true!!
>
> Another one (not as critical as the fsck though): when compiling the
> kernel, sometimes the kernel compilation is done, but the console output
> isn't finished yet (I'm serious).

Dunno about others, but I always pipe stdout to /dev/null when compiling
kernels. This way, everything important is still shown (warnings/errors)
as those go to stderr anyway, and all non-interesting stuff goes down
the drain.

/David Weinehall
_ _
// David Weinehall <tao@acc.umu.se> /> Northern lights wander \\
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