From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <200101040850.f048oN918835@denx.local.net> To: "Rolf Liu" cc: linuxppc-dev@lists.linuxppc.org Subject: Re: separate kernel as code segment and data segment for linux ppc ? From: Wolfgang Denk Mime-version: 1.0 Content-type: text/plain; charset=ISO-8859-1 In-reply-to: Your message of "Thu, 04 Jan 2001 09:45:55 +0800." <017b01c075f0$15265b50$bf0102c8@sc.mcel.mot.com> Date: Thu, 04 Jan 2001 09:50:23 +0100 Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: 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/