[[email protected]: bug#418: FAT32 FS's being modified???]

Yikes, that sounds serious!

Maybe I could put some debugging messages into the FAT write functions
to make them called a printk to announce when they perform a write,
and see whether they do.  I don't know how to account for this.

I'll ask him to boot with the prompt option and not automount the
filesystems, and see if he still observes a change.

----- Forwarded message from [email protected] -----

To: [email protected]
Cc: [email protected]
From: [email protected]
Date: Tue, 18 May 2004 17:57:11 GMT
Subject: bug#418: FAT32 FS's being modified???

Package: lnx-bbc
Version: http://www.lnx-bbc.org/images/bbc-2.1.iso
  ((Severity: Makes it unusable for my purpose.))

Summary:
LNX-BBC seems to modify about 6 bytes on Windows 98 FAT32 filesystems
it mounts. This seems to be the reason their free lists are screwed up
when I boot Windows 98SE on them after working with them in LNX-BBC.
I am unable to locate any mention of this in existing bug reports.

Details:
I have been using LNX-BBC to get to the dd command to make 
image snapshot backup copies of whole filesystems from my Windows 98SE
computer. Source disk is a 4 gigabyte SCSI drive with a full-sized FAT32 FS,
and the destination disk might be a Western Digital IDE 120 Gigabyte drive.

That was working fairly well, I thought. Until I ran "cmp -l" to verify that 
the two
copies were identical, as I hoped.  Just after running a 4 gigabyte dd, the two
copies are indeed identical.  If I then shutdown and reboot LNX-BBC, and run the
"cmp -l" again, they are no longer identical.  6 bytes are different, about 
1000 bytes
into the partition. On a different try with 30gig souce/2 partitions  to 120gig 
destination,
only the first partition is messed up.

If I boot Win 98SE  on the source (4 gig) disk,  and check the properties of the
C: drive, the free/used numbers are very wrong.
When I run scandisk it says that the free
space information is wrong in the partition information, and needs to fix it.
Doing that seems to clean up the problem.

I was under the impression that the LNX-BBC would not modify hard disks
or any filesystems it auto-mounted read-only.

What's actually happening ?  Why is the disk getting written to ?
Is it LNX-BBC or some other entity in the boot-up process ?

Thanks for any help or clarification.

(I am an old-time UNIX user/programmer from about 1978 on.  But I'm very
out of date with it, so I'm not up on the details of Linux and what it's trying
to do in your BBC.  I understand generally the UNIX/Linux approach though.
I do not have source code, I just downloaded the iso and booted it from CD.)

Paul Iddings
[email protected]





----- End forwarded message -----

-- 
Seth David Schoen <[email protected]> | Very frankly, I am opposed to people
     http://www.loyalty.org/~schoen/   | being programmed by others.
     http://vitanuova.loyalty.org/     |     -- Fred Rogers (1928-2003),
                                       |        464 U.S. 417, 445 (1984)