[daip] Re: BA048 (fwd)

[Pedro Manuel Augusto]

Dear Pat,

I am trying to solve the problem following your suggestions from the less
dangerous to the most dangerous one. To see if we solve it on the way.

On Wed, 26 Mar 2003, Patrick P Murphy wrote:

> On Wed, 26 Mar 2003 13:21:28 +0000 (GMT), Pedro Manuel Augusto
>    <augusto at uma.pt> said: 
> 
> > [root at augusto /]# df -kl /mnt/dados/AUGUSTO_1/
> > Filesystem           1K-blocks      Used Available Use% Mounted on
> > /dev/hda9             28886768   1119680  27767088   4% /mnt/dados
> 
> Fair enough; it's local (the filesystem isn't NFS, it's an IDE disk).

Correct. I have two IDE disks on a PC. The one with the AIPS area and
Linux has 40 Gb capacity. The other has the two windows systems (XP and
98). There is a windows-based initial boot to select if I start off with
windows or linux. I would have preferred to hardly use any windows, after
being in the Uk for three years and using unix all the time. However, when
I first came here nobody knew what unix or linux was... after 5 years of a
struggle I got finally a working version of linux. My dream of having AIPS
here in my PC (since it is not possible anywhere else dispite my attempts)
is (almost) conceded. Or I thought it was now that it seems that my all PC
system is probably wrong. Very annoying for a professor-observer!

 > 
> > [root at augusto /]# mount | grep /mnt/dados
> > /dev/hda9 on /mnt/dados type vfat (rw,umask=0)
> 
> Type VFAT: it's a windows filesystem.  This is part (or maybe all) of the
> problem.  VFAT files cannot support normal unix permissions.  In addition,
> the filesystem is not mounted with a uid= option; see the man page for
> mount, under "Mount options for fat":
> 

I did that (see file attached) but I cannot find what to do. Can you be
more specific? I would like to try this first before going on to the next
steps. By the way, I have Mandrake 8.0 Linux but for some reason (some
errors) I lost the man pages at some stage (I did have them when it was
freshly new installed). I have been using "info" for all other commands
but it cannot find "mount". So I copied the man page from another unix
system (in UK). Hope they should be the same...


>        (Note: fat is not a separate filesystem, but a common part of the
>        msdos, umsdos and vfat filesystems.)
> 
>        uid=value and gid=value
>               Set the owner and group of all files. (Default: the uid and
>               gid of the current process.)
> 
> Because they're not specified, they default to root.  If you have an aips
> user, you might want to mount that filesystem as uid=nnn where nnn is the
> numeric UID for the aips account.  But there are other problems:

I do. It is 200. Is nnn above hexadecimal? so it would get 0CB, or
something?

Let me know more about mount and I will try something.
Thanks for your help!

Pedro

> 
> > [root at augusto /]# id -a
> > uid=0(root) gid=0(root)
> > groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel),100(users)
> > [root at augusto /]# ls -la /mnt/dados/AUGUSTO_1/
> > total 91888
> > drwxrwxrwx    2 root     root        81920 Mar 25 10:58 ./
> > drwxrwxrwx    7 root     root        16384 Jan  1  1970 ../
> > -rwxrwxrwx    1 root     root         8192 Mar 25 10:36 AGD002001.05K;*
> > -rwxrwxrwx    1 root     root        10240 Mar 25 10:38 AND002001.05K;*
> 
> <snip>
> 
> This I don't understand.  The permissions are set so that anyone can do
> anything to the directory (./) and the files.  But you couldn't delete
> them. 
> 
> I suspect something to do with the VFAT file system is at fault here.  If
> the actual filesystem is NTFS, that could be it.  There are, or were,
> issues with Linux being able to write to such disks.  If it's an old
> fashioned FAT filesystem (your windows experts will understand the
> difference) then the uid= option and read/write access from Linux will
> work fine.  It may be that for your version of Linux, accessing a NTFS
> filesystem as VFAT may *appear* to be read/write, but is in fact readonly.
> 
> There's the possibility that things could clear up if you edited
> /etc/fstab (as root) to change the mount type to "ntfs".  This appears to
> be supported in my Red Hat 8.0 system (but I don't run windows [almost
> ever] so I don't have any NTFS filesystems to check this against.
> 
> The best solution would be to back up the files, convert the filesystem to
> EXT2 or EXT3, and restore them (and I realize this poses problems).  AIPS
> assumes a normal unix filesystem underneath everything, one that obeys the
> usual conventions of file user and group permissions, and NTFS mounted as
> a VFAT filesystem does not fit this definition.  I would not recommend
> using a NTFS or VFAT or FAT filesystem in production mode as an AIPS disk.
> 
> 				- Pat
>