linux-kernel - Re: Patches for REALLY TINY 386 kernels

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Date:	Fri, 20 Jul 2007 09:27:30 +0200
From:	Uwe Hermann <uwe@...mann-uwe.de>
To:	Matt Mackall <mpm@...enic.com>
Cc:	Andi Kleen <andi@...stfloor.org>, "H. Peter Anvin" <hpa@...or.com>,
	Jonathan Campbell <jon@...dgrounds.com>,
	linux-kernel@...r.kernel.org
Subject: Re: Patches for REALLY TINY 386 kernels

On Wed, Jul 18, 2007 at 03:41:02PM -0500, Matt Mackall wrote:
> On Wed, Jul 18, 2007 at 10:10:43PM +0200, Andi Kleen wrote:
> > 
> > I was waiting for someone to make that "point" ...
> > 
> > > 
> > > Every byte you can shave off the compressed kernel image is another
> > > byte you can use for userspace on your FLASH.
> > 
> > Now let's see if that 1MB 386 contains any flash at all. Guesses?  
> 
> I've certainly worked on such devices. I expect there are more of them
> still in service, than, say, Voyagers.
> 
> I haven't looked at whether this CPUID stuff is worth the trouble, I'm
> just responding to your argument about init code. Init code is
> definitely not free. It takes up storage space, which can be extremely
> valuable.

Ack.

Some people are putting Linux kernels in the "BIOS" (i.e. ROM chip) when
using LinuxBIOS (www.linuxbios.org). It _does_ make a lot of difference
there how big the kernel is. At the moment you can't do that with
anything smaller than a 1 MB chip. But if people could use 512 KB chips
because the kernel is small enough that would sure be a great thing.

In such scenarios every single byte matters.


Uwe.
-- 
http://www.hermann-uwe.de  | http://www.holsham-traders.de
http://www.crazy-hacks.org | http://www.unmaintained-free-software.org

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