Date: Sun, 15 Jan 2006 12:49:51 +0000 From: Brian Candler <B.Candler@pobox.com> To: freebsd-stable@freebsd.org Subject: Re: newfs_msdos onto an image file Message-ID: <20060115124950.GA23753@uk.tiscali.com> In-Reply-To: <20060115123445.GA14271@uk.tiscali.com> References: <20060115123445.GA14271@uk.tiscali.com>
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On Sun, Jan 15, 2006 at 12:34:46PM +0000, Brian Candler wrote: > I am trying to prepare an MS-DOS disk image file (for later dd to a USB > device) but am having difficulties getting newfs_msdos to work in this way. > This is under 5.4-RELEASE. P.S. it seems that the total disk size given by -s is in sectors not bytes (this isn't very clear in the manpage). This doesn't help the simple case: # newfs_msdos -h 64 -u 32 -s 256000 /dev/md0 newfs_msdos: Cannot get number of sectors, Operation not supported # newfs_msdos -h 64 -u 32 -s 256000 -S 512 /dev/md0 newfs_msdos: Cannot get number of sectors, Operation not supported But finally I found an incantation that works: # newfs_msdos -h 64 -u 32 -s 256000 -f 1440 -a 125 -F 16 -b 4096 -c 8 /dev/md0 /dev/md0: 255728 sectors in 31966 FAT16 clusters (4096 bytes/cluster) bps=512 spc=8 res=1 nft=2 rde=224 mid=0xf0 spf=125 spt=32 hds=64 hid=0 bsec=256000 # mount -t msdos /dev/md0 /mnt # df -k | grep md0 /dev/md0 127872 8 127864 0% /mnt That was a lot harder work than I was expecting, especially having to use trial-and-error on the sectors per FAT value. Is there any chance that newfs_msdos could gain some intelligence and be able to choose suitable default values? Furthermore, why do I still have to pretend that the device is a 1440K floppy disk? If I remove -f 1440 I get: # newfs_msdos -h 64 -u 32 -s 256000 -a 125 -F 16 -b 4096 -c 8 /dev/md0 newfs_msdos: Cannot get number of sectors, Operation not supported Regards, Brian.
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