Date: Tue, 22 May 2007 09:15:34 -0700 From: Sean Bruno <sbruno@miralink.com> To: Warner Losh <imp@bsdimp.com> Cc: freebsd-embedded@FreeBSD.org Subject: Re: [nanobsd] Calculation of new flash image size Message-ID: <46531726.9050907@miralink.com> In-Reply-To: <20070522.094257.74690293.imp@bsdimp.com> References: <465233FF.8060100@miralink.com> <20070522.094257.74690293.imp@bsdimp.com>
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Warner Losh wrote: > From: Sean Bruno <sbruno@miralink.com> > Subject: [nanobsd] Calculation of new flash image size > Date: Mon, 21 May 2007 17:06:23 -0700 > > >> If the manufacturer doesn't provide me with the specific values for >> NANO_SECTS, NANO_HEADS and NANO_MEDIASIZE, I assume that I would be able >> to use the output of fdisk to calculate it for me: >> >> fmybox# fdisk /dev/ad0 >> ******* Working on device /dev/ad0 ******* >> parameters extracted from in-core disklabel are: >> cylinders=993 heads=16 sectors/track=63 (1008 blks/cyl) >> >> parameters to be used for BIOS calculations are: >> cylinders=993 heads=16 sectors/track=63 (1008 blks/cyl) >> >> >> So in this case, NANO_SECTS=63, NANO_HEADS=16 and NANO_MEDIASIZE=(993 * >> 16 * 63)=1000944? >> >> I added the following to Flashdevices.sub: >> >> dom512m) >> # Source: sbruno@miralink.com >> NANO_MEDIASIZE=`expr 512483328 / 512` >> NANO_HEADS=16 >> NANO_SECTS=63 >> ;; >> > > The flashdevices.sub database is lame. It is a misfeature to require > it. > > >> If I do this for my new Transcend module, the system won't boot properly >> and freezes on the BTX boot loader startup. >> >> What am I doing wrong here? >> > > There's a fundamental flaw in nanobsd. That is that it requires one > to know the geometry of the target device. fdisk won't tell you this > when you are using a scsi card reader, so you can't find it out > automatically. This is because the scsi layer uses a fake geometry > here (I can't recall if it is FreeBSD software, or the card reader). > Nanobsd is supposed to use 'packet mode' so that geometry doesn't > matter. You should make sure that the CF/disk created is in packet > mode. > This is an IDE flash device, not a CF card or other memory stick-ish thing. > If you have a card that you've re-fdisked since you bought it, dd > about 30k of zeros to the front of it from /dev/zero. Then insert it > into a camera that can do the formatting of flash cards. Put that > back into your freebsd box and run fdisk again and see what the > partitions look like. > After wiping the flash disk, fdisk reports the same values. The only item of note is the "Warning" section. mybox# fdisk /dev/ad0 ******* Working on device /dev/ad0 ******* parameters extracted from in-core disklabel are: cylinders=993 heads=16 sectors/track=63 (1008 blks/cyl) parameters to be used for BIOS calculations are: cylinders=993 heads=16 sectors/track=63 (1008 blks/cyl) fdisk: invalid fdisk partition table found Media sector size is 512 Warning: BIOS sector numbering starts with sector 1 Information from DOS bootblock is: The data for partition 1 is: sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD) start 63, size 1000881 (488 Meg), flag 80 (active) beg: cyl 0/ head 1/ sector 1; end: cyl 992/ head 15/ sector 63 The data for partition 2 is: <UNUSED> The data for partition 3 is: <UNUSED> The data for partition 4 is: <UNUSED> I didn't retry as the values retrieved here are the same as I previously had used. Sean
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