Date: Sat, 02 Aug 2008 09:18:43 +0200 From: Harald Schmalzbauer <h.schmalzbauer@OmniLAN.de> To: freebsd-stable@freebsd.org Subject: newfs-msdos and default fat32 parameters Message-ID: <48940A53.3000004@OmniLAN.de>
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[-- Attachment #1 --] Hello, lately I wanted to create some DOS bootable SD-Cards (for simply BIOS updates, disk diagnostic tools etc...) After newfs_msdos -F32 -B VBR.bin (2.5G partition) the system just didn't continue booting after the MBR was loaded (VBR.bin is a 3 sectors dump of the DOS boot record which sys creates). When I directly wrote the dump back to sectors 63-65 and 69-71 the system booted! So I took my hex glasses and found some unfortunate default parameters of newfs_msdos. - MediaType is f0 but probably should read f8 (fixed disk) - The backup boot record should be located at offset 6, not 2. - There should be defined 63 hidden sectors With 'newfs_msdos -F32 -m 0xf8 -B VBR.bin -k 0x6 -o 63 -i 0x1 /dev/da6s1' every thing was fine. I'm no expert, I just found some FAT info. maybe the current defaults are wisley chosen. Maybe not? Best regards, -Harry [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) iEYEARECAAYFAkiUClMACgkQLDqVQ9VXb8gxpACgjQF431rTobR87z3zVVeD1e5T XSYAn0dXMKFzPtY9wubfSGiJvyHnfnxr =yy39 -----END PGP SIGNATURE-----
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