[linux-help] Re: Saving to a floppy disk

[Jeff Vian <jvian10@xxxxxxxxxxx>]

Dale W Hodge wrote:
>>-----Original Message-----
>>From: linux-help-bounce@xxxxxxxxx [mailto:linux-help-bounce@xxxxxxxxx]On
>>Behalf Of Jeff Vian
>>
>>A windows/dos formated floppy is NOT vfat.
>>It is msdos.
> 
> 
> I beg to differ. Long filename support is vfat, not dos. You can mount a 
> floppy
> with "-t vfat", in fact if you don't, you loose long filename support.

True on the long filename support, but not for the floppy format.
AFAIK the "auto" setting in the fstab for the floppy always picks vfat, 
but it is not necessary that it do so.

You can use a floppy formatted under dos 3.2 on a win98 machine and 
still use long filenames. In fact I have floppies that I have not used 
for many years and tried it successfully.
See the listing below.

VFAT is not exclusively the disk format, but rather the size of the 
blocks used, and the maximum number of sectors/blocks on the drive. (FAT 
vs VFAT). It was inplemented to support the larger drives that were 
beyond the range of the older filesystem structures on numbers of 
sectors on the drive. At the same time they added long filenames due to 
the limits of the 8.3 name structure and to allow expanded compatibility 
with other OSs that had used lfn for some time (*nix and MACos come to 
mind).

Since floppies still have the same tiny 512 byte sectors and the total 
disk space is still only 1.44mb there was no change.  What changed on 
the floppy for systems using long filenames was the directory usage. Use 
of long filenames on a windows system involves multiple directory 
entries for the same file regardless if it is msdos like the floppy or 
vfat like the hard disk. Illustration follows.

------
OTOH, long filenames involves multiple directory entries for the 
additional file name length and every file that has a long filename has 
a short AND a long filename in the directory. As far as I can tell, The 
long filename points to the short filename entry which then points to 
the file data.

For example, On the hard disk the directory we see in windows as 
"Program Files" has a standard short filename of "PROGRA~1" when you 
look at the data in the hex editor or from a dos version prior to win95. 
  In fact, the directory known as "Documents and Settings" when you open 
a command window under winXP displays as "C:/DOCUME~1" in the prompt, 
although doing a dir on the contents will display the long filenames.

> 
> 
>>The floppy has NEVER used the 32bit vfat formatting.
> 
> 
> This is probably correct, but it *is* vfat.
> 

Not true. the OS supports long filenames, but the disk is NOT vfat.
explanation above and illustrated below.

The fact that it can be mounted in different ways (either vfat or msdos) 
is not controlled by the disk format.
However, when mounted as vfat, lfn is supported and when mounted as 
msdos lfn is NOT supported.

This is a directory listing of a disk created in 1992 by me, with one 
file added today for display purposes.  It CERTAINLY is not vfat, since 
vfat was not available until after Windows 95 was released. This disk 
was created using Dos 4.01 or Dos 5.0 (hard to remember which I was 
using that far back). :-)

-- mounted as msdos
[root@wannabe /]# mount -t msdos /dev/fd0 /mnt

-- the listing when mounted as msdos
[root@wannabe /]# ls /mnt
ee.zip  flink.zip  hoyle.zip  longfi~1  mavis.zip  ts.zip
                               ^^^^^^^^
-- the long filename is not available
[root@wannabe /]# ls  /mnt/long\ filename
ls: /mnt/long filename: No such file or directory

-- mounted as vfat
[root@wannabe /]# mount -t vfat /dev/fd0 /mnt

-- the listing when mounted as vfat
[root@wannabe /]# ls /mnt
ee.zip  flink.zip  hoyle.zip  long filename  mavis.zip  ts.zip
                               ^^^^^^^^^^^^^
-- the short filename is also available in vfat
[root@wannabe /]# ls /mnt/longfi~1
/mnt/longfi~1


Note, as Dale said, long filename support does not exist when mounted as 
msdos and is available when mounted as vfat.
However, that is an os specific thing related to display and handling of 
directory entries and not based on format of the floppy.


> 
> --dwh
> 
> ---
> Dale W Hodge - dwh@xxxxxxxxxxxxxxxx
> Vice Chairman & Secretary - info@xxxxxxxxx
> Air Capital Linux User's Group  (ACLUG)
> ---
-- 
Jeff Vian
jvian10@xxxxxxxxxxx

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