Date: Wed, 25 Sep 2002 07:18:01 +0200
From: Robert Schwebel <robert@schwebel.de>
To: "Michael D. Crawford" <crawford@goingware.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Conserving memory for an embedded application
Message-ID: <20020925051801.GQ10741@pengutronix.de>
References: <3D91413C.1050603@goingware.com>
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On Wed, Sep 25, 2002 at 12:53:16AM -0400, Michael D. Crawford wrote:
> I am helping my client design an embedded hardware device that we may
> run Linux on. An important concern is to minimize the amount of ROM
> and flash ram that the device has, both to save manufacturing cost and
> to minimize power consumption.

IMHO this isn't worth the efford. Flash is slow and (per kbyte) more
expensive than RAM, so I would'n waste too much time on this if you
don't plan to make more than >10000 pieces of your device. If you care
for power consumption use another architecture than x86. 

> It would also be helpful if a filesystem image containing a user program 
> could be burned into flash, and then the program run directly out of flash. 

Use jffs2 for the root file system. 

> Also, what is the minimum amount of physical ram that you think I can
> get any version of the kernel later than 2.0 or so to run in?  I heard
> somewhere that someone can boot an x86 system with as little as 2MB of
> RAM. Is that the case?

This depends on which drivers you need, how much stuff you need in
userspace and how memory hungry your application is. Running a 2.4
kernel with busybox/uclibc in 2 MB RAM is possible. 

Robert
-- 
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