Re: LILO and serial speeds over 9600

James Sutherland
2001-02-12T22:48:09Z

On Mon, 12 Feb 2001, Alan Cox wrote:

> > > I have toyed a few times about having a simple Ethernet- or UDP-based
> > > console protocol (TCP is too heavyweight, sorry) where a machine would
> > > seek out a console server on the network. Anyone has any ideas about
> > > it?
> >
> > Excellent plan: data centre sysadmins the world over will worship your
> > name if it works...
>
> Sounds like MOP on the old Vaxen. TCP btw isnt as heavyweight as people
> sometimes think. You can (and people have) implemented a simple TCP client
> and IP and SLIP in 8K of EPROM on a 6502. There is a common misconception
> that a TCP must be complex.
>
> All you actually _have_ to support is receiving frames in order, sending one
> frame at a time when the last data is acked and basic backoff. You dont have
> to parse tcp options, you dont have to support out of order reassembly.

It's not a huge undertaking, I know, but UDP will probably still be
a bit simpler. Turn the question around: would using TCP bring any real
benefits, in a system which will only be used to shift a few kb each boot
time?

At a later date, perhaps TCP could be used - it would certainly make sense
for the kernel-side code: once you have a fully-fledged IP stack, why not
use it. There's no reason the server couldn't support both, and machines
would just use whichever was more appropriate at the time.

James.