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From: Wolfgang Denk <wd@denx.de>
To: "Rolf Liu" <rolfl@sc.mcel.mot.com>
Cc: linuxppc-dev@lists.linuxppc.org
Subject: Re: separate kernel as code segment and data segment for linux ppc ?
Date: Thu, 04 Jan 2001 09:50:23 +0100	[thread overview]
Message-ID: <200101040850.f048oN918835@denx.local.net> (raw)
In-Reply-To: Your message of "Thu, 04 Jan 2001 09:45:55 +0800." <017b01c075f0$15265b50$bf0102c8@sc.mcel.mot.com>


In message <017b01c075f0$15265b50$bf0102c8@sc.mcel.mot.com> you wrote:
>
> As all know, the kernel is resided in flash rom, then upon power-on, kernel
> is copied to RAM.
> I wonder if I can just put data segment to ram and leave code segment to
> FLASH, just as uClinux
> has done. such method will save some ram space, which makes sense on
> embedded solutions.

Does it really make sense? Flash is  more  expensive  than  RAM,  and
sometimes slower (especially if you have just a 8 or 16 bit wide boot
device). For all systems I've seen so far it was more efficient to be
able  to  store  a  compressed  image  in  flash, to reduce the flash
footprint on the expense of some RAM.

This has been discussed several times before on  this  mailing  list;
you might want to search the archives for all the other arguments pro
and contra.

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Man is the best computer we can put aboard a spacecraft ...  and  the
only one that can be mass produced with unskilled labor.
                                                  - Wernher von Braun

** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

      parent reply	other threads:[~2001-01-04  8:50 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-01-04  1:45 separate kernel as code segment and data segment for linux ppc ? Rolf Liu
2001-01-04  3:14 ` separate kernel as code segment and data segment for linux p Gary Thomas
2001-01-04  3:49   ` Rolf Liu
2001-01-04  4:07   ` Critical section - pSOS+ Srinivas Rao.M
2001-01-04 21:03     ` Jerry Van Baren
2001-01-05  5:19       ` Srinivas Rao.M
2001-01-04 18:07   ` separate kernel as code segment and data segment for linux p Dan Malek
2001-01-04  8:50 ` Wolfgang Denk [this message]

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