Image recovery: Recovering fragmented image files from flash memorycards

[Hans-Peter Diettrich]

Then familiarize with the new features of FAT32, before posting
nonsense ;-]

And if you took the time to study how FSI_Nxt_Free is implemented, you
wouldn't keep posting stuff like this. FSI_Nxt_Free points to the lowest
available cluster. Nothing more & nothing less. Nowhere is is said that
there can't be any used clusters after this. Get it?

"Typically this value is set to the last cluster number that the driver
allocated. "

Which part of that description did you not understand?

Hint: "allocated" is not "released".

DoDi

 

[cmyk]

"Typically this value is set to the last cluster number that the driver allocated. "

Which only goes to prove my point - 'typically' is not mandated behaviour and, as I said from the outset, that "is a task for the OS
or, perhaps, the media controller" - FAT32 does not do this of itself. Why don't you pay attention???

 

[Phil Carmody]

You have read about FSInfo.FSI_Nxt_Free?

Isn't that a write pointer?

Given that one term has already been coined for it, there's
no need to coin another one. Economy of nomenclature.

So you think that the system scans the FAT, each time a cluster has to
be allocated to an file or directory?

My god, you really are as stupid as I first suspected!

No I do not think that at all.

What on earth made you think a scan would be required every time?
That's what maintaining such an index is for, so you don't have
to scan. Think about which operations could make that index change,
and whether the system knows what it would change to after
completion of those operations.

This is in agreement with all the prior FAT systems that I have been
familiar with.

Then familiarize with the new features of FAT32, before posting nonsense ;-]

Care to provide citations for where the standards deviate in
this regard?

Damn, I'd forgotten that I said I wasn't going to waste time
spoon feeding someone who has painted himself from head to toe
in KlooRezist. Due to lack of compression content, I'm removing
comp.compression from followups so I don't have to suffer your
no-doubt inane and ill-conceived reply.

Phil

 

[Phil Carmody]

Which only goes to prove my point - 'typically' is not mandated
behaviour and, as I said from the outset, that "is a task for the OS
or, perhaps, the media controller" - FAT32 does not do this of
itself. Why don't you pay attention???

Ah, so they're covering their backs. Their "typical" behaviour
is of no practical use in a scenario where the total amount of
data written is larger than the capacity of the storage medium,
and if anyone complains about that they can just say "well,
we didn't force you to use that technique".

OK, I admit it, MS have made their file system design worse
over time in this regard. However, they're at least not hiding
the fact.

However, as you say, they certainly aren't mandating the
behaviour claimed by HPD.

Didn't IBM teach them about proper file systems over a decade
ago?

Phil

 

[George Johnson]

Tonny Iversen wrote:

| Hello. I'm trying to figure out if it exists any software that might
| be able to recover fragmented images from flash memory cards /
| digital cameras if the card was quick-formatted (i.e. if the card has
| a zeroed out FAT), or some details about the jpeg algorithm to figure
| out how difficult development of such would be.
|
| My main interest is for .jpg/.jpeg files.
|
| In the situation when the FAT contains only zeroes, recovery of
| non-fragmented image files seems to be easy for many (or maybe
| most?/all?) file / image /data recovery software products, but I
| haven't been able to find any that can recover anything more than the
| first fragment of the file if the file is fragmented.

TESTDISK

It saved my hard drive when the boot blocks went screwy for no logical
reason a while back. I am replying off the very same hard drive that
TESTDISK recovered. Best of all, it's open source and thusly free to use.

Don't thank me, just be thankful that there is a kind soul out there
that put the effort into creating such a wonderful program that you can use
for free.

==============

To recover lost pictures or files from digital camera or harddisk, run the
PhotoRec command.
http://www.cgsecurity.org/wiki/PhotoRec

PhotoRec is file data recovery software designed to recover lost files
including video, documents and archives from Hard Disks and CDRom and lost
pictures (thus, its 'Photo Recovery' name) from digital camera memory.
PhotoRec ignores the filesystem and goes after the underlying data, so it
will still work even if your media's filesystem has been severely damaged or
re-formatted.

PhotoRec is free, this open source multi-platform application is distributed
under GNU Public License. PhotoRec is a companion program to TestDisk, an
app for recovering lost partitions on a wide variety of filesystems and
making non-bootable disks bootable again. You can download them from this
link.

For more safety, PhotoRec uses read-only access to handle the drive or
memory support you are about to recover lost data from. Important: As soon
as a pic or file is accidentally deleted, or you discover any missing, do
NOT save any more pics or files to that memory device or hard disk drive;
otherwise you may overwrite your lost data. This means that even using
PhotoRec, you must not choose to write the recovered files to the same
partition they were stored on.

Operating systems

PhotoRec runs under

* DOS/Win9x
* Windows NT 4/2000/XP/2003
* Linux
* FreeBSD, NetBSD, OpenBSD
* Sun Solaris
* Mac OS X

and can be compiled on almost every Unix system.
Filesystems

Photorec ignores the filesystem, this way it works even if the filesystem is
severely damaged.
It can recover lost files at least from

* FAT,
* NTFS,
* EXT2/EXT3 filesystem
* HFS+

ReiserFS includes some special optimizations centered around tails, a name
for files and end portions of files that are smaller than a filesystem
block. In order to increase performance, ReiserFS is able to store files
inside the b*tree leaf nodes themselves, rather than storing the data
somewhere else on the disk and pointing to it. Unfortunately, PhotoRec isn't
able to deal with this, it's why it doesn't work well with ReiserFS.
Media

PhotoRec works with HardDisks, Cdrom, Compact Flash, Memory Stick,
SecureDigital, SmartMedia, Microdrive, MMC, USB Memory Drives...
PhotoRec has been successfully tested with the following Digital Camera

* Canon EOS300D, 10D
* HP PhotoSmart 620, 850, 935
* Nikon CoolPix 775, 950, 5700
* Olympus C350N, C860L, Mju 400 Digital, Stylus 300
* Sony DSC-P9
* Praktica DCZ-3.4
* Casio Exilim EX-Z 750

Known file format

PhotoRec searches known file header and because there is no data
fragmentation (usually), it can recover the whole file. Photorec recognises
numerous file format including ZIP, Office, PDF, HTML, JPEG and various
graphics file formats. The whole list of file formats recovered by PhotoRec
contains more than 80 file extensions.

================

http://www.cgsecurity.org/wiki/TestDisk
TestDisk home: http://www.cgsecurity.org.


is OpenSource software and is licensed under the GNU Public License (GPL).

TestDisk is a powerful free data recovery software! It was primarily
designed to help recover lost partitions and/or make non-booting disks
bootable again when these symptoms are caused by faulty software, certain
types of viruses or human error (such as accidentally deleting your
Partition Table). Partition table recovery using TestDisk is really easy.

TestDisk can

* Fix partition table, recover deleted partition
* Recover FAT32 boot sector from its backup
* Rebuild FAT12/FAT16/FAT32 boot sector
* Fix FAT tables
* Rebuild NTFS boot sector
* Recover NTFS boot sector from its backup
* Fix MFT using MFT mirror
* Locate ext2/ext3 Backup SuperBlock

TestDisk has features for both novices and experts. For those who know
little or nothing about data recovery techniques, TestDisk can be used to
collect detailed information about a non-booting drive which can then be
sent to a tech for further analysis. Those more familiar with such
procedures should find TestDisk a handy tool in performing onsite recovery.
Operating systems

TestDisk can run under

* DOS (either real or in a Windows 9x DOS-box),
* Windows (NT4, 2000, XP, 2003),
* Linux,
* FreeBSD, NetBSD, OpenBSD,
* SunOS and
* MacOS

Source files and precompiled binary executables are available for DOS,
Win32, MacOSX and Linux from the download page
Filesystems

TestDisk can find lost partitions for all of these file systems:

* BeFS ( BeOS )
* BSD disklabel ( FreeBSD/OpenBSD/NetBSD )
* CramFS, Compressed File System
* DOS/Windows FAT12, FAT16 and FAT32
* HFS and HFS+, Hierarchical File System
* JFS, IBM's Journaled File System
* Linux Ext2 and Ext3
* Linux Raid
o RAID 1: mirroring
o RAID 4: striped array with parity device
o RAID 5: striped array with distributed parity information
o RAID 6: striped array with distributed dual redundancy
information
* Linux Swap (versions 1 and 2)
* LVM and LVM2, Linux Logical Volume Manager
* Mac partition map
* Novell Storage Services NSS
* NTFS ( Windows NT/2K/XP/2003/Vista )
* ReiserFS 3.5, 3.6 and 4
* Sun Solaris i386 disklabel
* Unix File System UFS and UFS2 (Sun/BSD/...)
* XFS, SGI's Journaled File System