| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | BFS FILESYSTEM FOR LINUX |
| 2 | ======================== |
| 3 | |
| 4 | The BFS filesystem is used by SCO UnixWare OS for the /stand slice, which |
| 5 | usually contains the kernel image and a few other files required for the |
| 6 | boot process. |
| 7 | |
| 8 | In order to access /stand partition under Linux you obviously need to |
| 9 | know the partition number and the kernel must support UnixWare disk slices |
| 10 | (CONFIG_UNIXWARE_DISKLABEL config option). However BFS support does not |
| 11 | depend on having UnixWare disklabel support because one can also mount |
| 12 | BFS filesystem via loopback: |
| 13 | |
| 14 | # losetup /dev/loop0 stand.img |
| 15 | # mount -t bfs /dev/loop0 /mnt/stand |
| 16 | |
| 17 | where stand.img is a file containing the image of BFS filesystem. |
| 18 | When you have finished using it and umounted you need to also deallocate |
| 19 | /dev/loop0 device by: |
| 20 | |
| 21 | # losetup -d /dev/loop0 |
| 22 | |
| 23 | You can simplify mounting by just typing: |
| 24 | |
| 25 | # mount -t bfs -o loop stand.img /mnt/stand |
| 26 | |
| 27 | this will allocate the first available loopback device (and load loop.o |
| 28 | kernel module if necessary) automatically. If the loopback driver is not |
| 29 | loaded automatically, make sure that your kernel is compiled with kmod |
| 30 | support (CONFIG_KMOD) enabled. Beware that umount will not |
| 31 | deallocate /dev/loopN device if /etc/mtab file on your system is a |
| 32 | symbolic link to /proc/mounts. You will need to do it manually using |
| 33 | "-d" switch of losetup(8). Read losetup(8) manpage for more info. |
| 34 | |
| 35 | To create the BFS image under UnixWare you need to find out first which |
| 36 | slice contains it. The command prtvtoc(1M) is your friend: |
| 37 | |
| 38 | # prtvtoc /dev/rdsk/c0b0t0d0s0 |
| 39 | |
| 40 | (assuming your root disk is on target=0, lun=0, bus=0, controller=0). Then you |
| 41 | look for the slice with tag "STAND", which is usually slice 10. With this |
| 42 | information you can use dd(1) to create the BFS image: |
| 43 | |
| 44 | # umount /stand |
| 45 | # dd if=/dev/rdsk/c0b0t0d0sa of=stand.img bs=512 |
| 46 | |
| 47 | Just in case, you can verify that you have done the right thing by checking |
| 48 | the magic number: |
| 49 | |
| 50 | # od -Ad -tx4 stand.img | more |
| 51 | |
| 52 | The first 4 bytes should be 0x1badface. |
| 53 | |
| 54 | If you have any patches, questions or suggestions regarding this BFS |
| 55 | implementation please contact the author: |
| 56 | |
| 57 | Tigran A. Aivazian <tigran@veritas.com> |