From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <22751.12.148.147.242.1048889638.squirrel@nevil.org> Date: Fri, 28 Mar 2003 16:13:58 -0600 (CST) Subject: Re: Flash File System Concerns From: "Daris A Nevil" To: In-Reply-To: <20030328171108.15068.qmail@web41213.mail.yahoo.com> References: <3E82F7F6.A1C684F@lucent.com> <20030328171108.15068.qmail@web41213.mail.yahoo.com> Cc: , Reply-To: dnevil@snmc.com MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Prakash, You don't have to worry about the /proc filesystem, as it is indepedent of your Disk or Flash filesystem. I usually point the /var/log directory to a RAMDISK. Regards, Daris SNMC Prakash kanthi said: > > Folks, > > I have one concern regarding FFS. If you use flash for > your entire filesystem including /var/log, /proc, > etc.., you will be accessing flash too many times. > > And there is good chance that, your flash on the board > reaches maximum number of accesses/writes limited by > flash technology. > > How do people generally handle that in the industry. > Especially, if you have on-board (non-replaceable) > flash? > > Thanks, > Prakash > > > Jaap Jan: Thank you very much for precise > instructions. > > > > > --- Jaap-Jan Boor wrote: >> Prakash, >> >> You should divide your flash into parts. e.g.: >> >> - first block(s) boot >> - then some blocks for the kernel >> - all remaining blocks as root fs >> >> You do this partitioning in the maps directory of >> drivers/mtd. >> >> You can make a linux kernel with mtd and jffs2 >> support and ramdisk that >> holds the erase, eraseall, dd, mkfs.jffs2 etc. >> programs. >> >> You can load the kernel into SDRAM, run it, prepare >> your flash (erase flash, then use mkfs.jffs2 on a >> /dev/mtd? device >> to prepare an fs. >> >> You should then make a new kernel that uses mtd as >> rootfs, not >> the ramdisk as rootfs. >> >> Jaap-Jan >> >> Prakash kanthi wrote: >> > >> > Hi Jaap Jan, >> > >> > Thanks for your reply. What do you mean by 'works >> out >> > of the box with denx'? I see the code you referred >> to >> > but not sure how to use it. I still have some >> > concerns. Like, >> > >> > 1. How can i initially store the image into flash? >> My >> > flash chip is on the board. >> > 2. How can i boot linux from flash? >> > >> > 3. Currently i have a 32MB SDRAM along with flash. >> I >> > have tools to download linux image into SDRAM. >> Even if >> > i go with MTD/JFFS, my concern is unless linux >> runs >> > flash can not be accessed and vice versa. >> > >> > 4. Lets say, i download linux into a safe place in >> > SDRAM, boot it and then access flash thru MTD/JFFS >> and >> > store linux image into flash. Even in this case, >> what >> > all i need to take care of for making my flash a >> boot >> > device. >> > >> > Any detailed documentation is appreciated. >> > >> > Thanks, >> > Prakash >> > >> > --- Jaap-Jan Boor wrote: >> > > Hi, >> > > >> > > I use strata flash with MTD and JFSS2 as file >> system >> > > on top of it. Works out of the box with denx' >> eldk >> > > kernel and >> > > toolchain. I've provided my own flash map but >> you >> > > can also use an existing one (look e.g. in >> > > linux/drivers/mtd/maps) >> > > >> > > Jaap-Jan >> > > >> > > Wolfgang Denk wrote: >> > > > >> > > > In message >> > > >> <20030326070131.88176.qmail@web41202.mail.yahoo.com> >> > > you wrote: >> > > > > >> > > > > I have a 32MB Intel Strata flash on my >> PPC405 >> > > based >> > > > > custom board. I need to create access >> > > routines/APIs to >> > > > > access the flash. I was thinking of creating >> a >> > > Flash >> > > > > File System and mount it as a device in >> Linux >> > > > > environment. >> > > > > >> > > > > Are there any off the shelf FFS packages >> > > available? >> > > > > Generally, how the flash is used? >> > > > >> > > > Use the MTD layer. >> > > > >> > > > > I am working with micro-monitor to use its >> Tiny >> > > File >> > > > > System on flash support and eventually mount >> > > into >> > > > > linux. Did anyone use this combination >> before? >> > > > >> > > > I think you cannot do this. AFAIK the TFS code >> is >> > > not available under >> > > > a GPL compatible license which prevents it >> from >> > > being linked with the >> > > > Linux kernel code. >> > > > >> > > > Best regards, >> > > > >> > > > Wolfgang Denk >> > > > >> > > > -- >> > > > Software Engineering: Embedded and Realtime >> > > Systems, Embedded Linux >> > > > Phone: (+49)-8142-4596-87 Fax: >> (+49)-8142-4596-88 >> > > Email: wd@denx.de >> > > > There is is no reason for any individual to >> have a >> > > computer in their >> > > > home. -- Ken Olsen (President of Digital >> > > Equipment Corporation), >> > > > Convention of the World Future >> > > Society, in Boston, 1977 >> > > > >> > > >> > > -- >> > > J.G.J. Boor >> > > Room: BE-525 >> > > Lucent Technologies Nederland b.v. >> > > Phone: +31 35 687 4721 >> > > Optical Networking Group TMS Data >> > > Fax: +31 35 687 5976 >> > > P.O. Box 1168, 1200 BD, Hilversum, The >> Netherlands >> > mailto:jjboor@lucent.com >> > >> >> -- >> J.G.J. Boor >> Room: BE-525 >> Lucent Technologies Nederland b.v. >> Phone: +31 35 687 4721 >> Optical Networking Group TMS Data >> Fax: +31 35 687 5976 >> P.O. Box 1168, 1200 BD, Hilversum, The Netherlands > mailto:jjboor@lucent.com > > Daris A Nevil Simple Network Magic Corporation 401 Kentucky McKinney, Texas 75069 http://www.snmc.com 972-562-3751 ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/