Messages in this thread | | | Date | Thu, 28 Mar 1996 18:45:53 +0100 (MET) | From | Gerd Knorr <> | Subject | Re: Any "file" utility for partitions? |
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On Wed, 27 Mar 1996, Bjorn Ekwall wrote:
> > Played around a bit, and found a relativ simple way to identify all my > > ext2-partitions: > [patch deleted] > > ----------------fs_magic file > > 0x0438 short 0xef53 ext2-fs > > ---------------- > [...] > > Nice! > > Now we only have to be able to recognize cdroms (iso9660), minix, ext, > xiafs, nfs ( :-)), hpfs, sysv, fat and vfat (with umsdos) > and perhaps a few others... > Just add them to the magic file...
# magic file to identify filesystems #--------------------------------------------------------------------------
# minix filesystem # short (14 char) filenames 0x0410 short 0x137f minix >0x0412 short 0x0001 (clean) # long (30 char) filenames 0x0410 short 0x138f minix >0x0412 short 0x0001 (clean)
# extended filesystem 0x0438 short 0x137d ext
# secound extended filesystem 0x0438 short 0xef53 ext2 >0x043a short 0x0001 (clean)
# xiafs 0x0638 long 0x012fd16d xiafs
# CD-ROM 0x8001 string CD001 iso9660 # high sierra?
# MS-DOS (and umsdos) hmm, the FAT starts with 0xfff8 always (right?) # not a real good magic, that's why we test it last... 0x0200 short 0xfff8 msdos
(PS: hav'nt tested ext and xiafs)
As you can see, its no problem to check the clean flag (for minix and ext2) too, this may be intresting for a desaster boot disk.
The fat-family (msdos,umsdos,vfat) is a special case. But if you know it is a fat fs, you can mount it as msdos and check for a /linux/--linux-.--- (?) file to find if this can be a umsdos root-fs.
> Finding the set of possible root filesystems can be done by mounting > and looking for some significant file(s). > I think /sbin/init and/or /etc/init can be rather good candidates... > How about /etc/fstab ? This allows some extra checks :-)
On the other side it is overkill to mount all filesystems just for checking which of one is the root filesystem (and you can't be sure it works), at least for every day useage.
It's ok for installing (better updating, else you hav'nt a root-fs) a linux system or for a generic desaster boot floppy.
Gerd
Gerd Knorr <kraxel@cs.tu-berlin.de> | http://www.cs.tu-berlin.de/~kraxel/
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