This is just a quick heads up. It was new to me and I had never came across the issue before on here, so I am posting my results.
I was doing some routine maintenance on my PC and I had accidentally left one of my external USB Stick drives in the machine. I noticed that in the Defrag options, it now gave me an option to Defrag the external drive. I thought to myself, thats kinda cool, I bet my 6gb Micro SD card on my phone could benift from a good defrag. I quickly popped my Micro SD card from my phone, plunked it into a USB Key Reader and told Diskeeper to Defrag the Micro Card. I was thinking, this should be great, I have thousands of files on my Micro Card, a good Defrag should be a cool thing. A few mins later it said it was done so I pulled it out and put it in back in my phone.
The next day I went to launch TomTom and it took 5 mins just to launch the app. I thought it had froze or something. I was fighting with it, driving me nuts. I re-installed TomTom, still taking 5-8mins now to load the app. When I tried to get directions it would take up to a min just to plot a route. (should only take a few seconds) I re-flashed the phone with a new ROM, then reinstalled TomTom and it did not help at all. Everything on the storage card was taking forever to load. Even the music apps were bogging down really badly.
Today, I yanked the Micro Card out of the phone, placed it in a USB key and copied the contents to a temp Dir on my desktop, formated the card, then wrote some data to the card and formated again.
Finally I put all my data from the temp Dir back onto the card and put the card back in my phone. Launched TomTom and took about 5 seconds rather than 5 mins to load. Everything is back to perfect.
I was hoping to Increase speeds with the Defrag of the Micro SD card and in fact it killed it horribly.
Lol, good to know. I would have thought the same thing!
a little common sense would have told you that would be a bad idea.
defragging is designed to 'defragment' files and put the most used files all together at the start of the drive. meaning a hdd head doesn't have to do a lot of skipping about for one file. then yet more skipping to find the next file, and a whole load more skipping to find different pieces of that file, etc etc.
the fact that solid state media doesn't have a drive head renders defragmenting unnecessary, plus as SSDs also have a limited number of write cycles the excessive writing required to move files around the card reduces its lifespan.
hope this helps
It depends
After owning several Pocket PCs with various expansion types, defragging has it's benefits and it's pitfalls.
(The following comments are based on percieved experience. I've not done any benchmarking.)
I've found using cheap card readers can definitely cause problems with cards, particularly when defragging. It can result in various errors in the files and sometimes even render the card unreadable/unwritable. Even reformatting has no effect. To solve the problem I've often had to use a digital camera to reformat the card before it can be read/written by a PC via card reader.
Multi-media files seem to be the type of file that benefits most from a contiguous file that needs to be read/written by the Windows Mobile device. Particularly video. Why this is so, I do not know. But when watching video or listening to audio skipping and stuttering seem to be much less aparent when the file is contiguous. Also, I've been able to resurrect some .jpg files unreadableby my WM device by doing a defrag. Again, no idea why.
Almost any file that needs to be constantly read seems to benefit from a contiguous file, e.g. GPS maps.
Safest way to make files contiguous is to copy the contents of the card to a hard disk, reformat the card, then rewrite to the card.
Just my 2 cents.
Would be interested in anyone else's observations, particularly with media files.
Defragging files on flashcards is pointless - skipping from sector to sector in a row takes as much time as to skip into random sectors...
Frequent writes on cards descrease their lifetime... So that - defragging anything else than hard disks is harmful for media.
maybe unrelated, but is the option "encrypt files in the storage" (or something sounds like that) from within the windows mobile's settings pose any danger? i.e. conflicting with PIM backup files etc.
thanks
Please read
Just found this article
dave852 said:
a little common sense would have told you that would be a bad idea.
defragging is designed to 'defragment' files and put the most used files all together at the start of the drive. meaning a hdd head doesn't have to do a lot of skipping about for one file. then yet more skipping to find the next file, and a whole load more skipping to find different pieces of that file, etc etc.
the fact that solid state media doesn't have a drive head renders defragmenting unnecessary, plus as SSDs also have a limited number of write cycles the excessive writing required to move files around the card reduces its lifespan.
hope this helps
Click to expand...
Click to collapse
Well said, SD cards and USB drives are flash drives and as so they don't need defragmentation and also as it was mentioned in the quote, it reduces it's lifespan.
Cheers
With Sandisk offering a 5-year limited warranty for their ordinary microSDHC and a 10-year limited warranty on their Ultra microSDHC cards and an expected minimum life of 15 years and maximum of 75 years (according to a Sandisk forum moderator) does it really matter what you do?
With storage memory sizes and formats moving so fast, who expects to keep using these things bought today on a daily basis on 5 or even 10 years' time?
Weirdest problem today on my month-old Touch HD.
I have a 16GB microSD card with about 2GB free. The camera is set to Photo mode (single shot) Fine. But after 18 snaps I couldn't take any more pics - the system shows the message:
Unable to capture photo. Disk full.
But there's 2GB of free space on the storage card, so this error is false.
Changing the storage destination to Main Memory resolves the immediate problem so I can at least take pics.
Deleting the 18 JPGs and one mp4 video in the DCIM folder on the storage card allowed me to take pics again. Irritating bug.
Anyone else come across this?
Had the same problem when my 8GB card was almost half full....would only allow me to take a few pics. I then wanted to see what happens when I fill the card up even more.....after going beyond 50% card space, all of a sudden remaining pics would show something like 7000+. Altough your problem appears to bit slightly different....
AFW said:
Weirdest problem today on my month-old Touch HD.
I have a 16GB microSD card with about 2GB free. The camera is set to Photo mode (single shot) Fine. But after 18 snaps I couldn't take any more pics - the system shows the message:
Unable to capture photo. Disk full.
But there's 2GB of free space on the storage card, so this error is false.
Changing the storage destination to Main Memory resolves the immediate problem so I can at least take pics.
Deleting the 18 JPGs and one mp4 video in the DCIM folder on the storage card allowed me to take pics again. Irritating bug.
Anyone else come across this?
Click to expand...
Click to collapse
Got same with 3.5gb left on a 16gb card but not been unable to capture photo yet. One minute it tells me I've got space for 5676, another time it will be 646 and sometimes goes down to 94. Not sure what the problem is but I don't want to be let down by it as I use it for work. I wonder if a good old soft reset would reset the card reading or removing and reinserting the card. That's what I will try if I get stuck anyway.
the same problem occured with my device, it said, that I can take only 3 pics, in full quality, while storage card was almost empty. But after that, I´ve deleted one 800MB file (mp4 movie) and now I can take more than 1400 pics. Anyone experienced something like this? Might be something with file system...
A fix....I think?!
Hi guys, this is my first post on XDA so go easy on me.
I ALSO had this problem where suddenly I had a '0' count on photos left to take, yet 4GB free on the same 8GB card.
This is how I fixed it:
1. Connect the HD to the computer and select 'Disk Drive' rather than 'Activesync'.
2. Defragment the SDCard using the command 'defrag e:' or whatever letter your card has connected as.
When the defrag is done disconnect and try to take photos again.
My 'photos remaining' count went from 0 to 6700 after this!
While this appears to be a way of fixing it, its HTC that need to address this problem with a patch.
Theres likely to be defrag programs for WinMob as well that could do the trick.
Matt
entityuk said:
Hi guys, this is my first post on XDA so go easy on me.
I ALSO had this problem where suddenly I had a '0' count on photos left to take, yet 4GB free on the same 8GB card.
This is how I fixed it:
1. Connect the HD to the computer and select 'Disk Drive' rather than 'Activesync'.
2. Defragment the SDCard using the command 'defrag e:' or whatever letter your card has connected as.
When the defrag is done disconnect and try to take photos again.
My 'photos remaining' count went from 0 to 6700 after this!
While this appears to be a way of fixing it, its HTC that need to address this problem with a patch.
Theres likely to be defrag programs for WinMob as well that could do the trick.
Matt
Click to expand...
Click to collapse
Not bad for a first post!
Welcome to the addiction!!
Further to my last post...
According to this: http://forum.xda-developers.com/showthread.php?t=433818 Defragging your MicroSD is a bad idea.
I certainly didn't experience any issues, it ran my storage card based Sat Nav software fine.
If your concerned that a defrag will damage your card (I certainly have no concerns) then move the contents of your card to the computer, format the SD Card and move the files back again and don't worry about the defrag.
entityuk said:
...
Worst case scenario is moving the contents of your card to the computer, formatting SD Card and moving the files back over again....
Click to expand...
Click to collapse
well i think this is pointless copying all the files to ur PC, deleting any SD crap and then copy them back to the card will actually defrag them (i think)..
Cause it will copy one file at a time
Problem is with one of the files being corrupted, resulting in false oversize file.
Solution to this is either completely formatting SD card, or using scandisk in windows.
ok.
my SDCard is ****ed, basically. i thought a good old format would do the trick but i was sadly mistaken.
it can read and display pictures, but cannot display thumbnails.
it shows mp3 files in file managers but wont play them in any music player.
will sometimes let me copy files from the card to the computer but not the other way round.
files cannot be deleted from the card at all.
and now the strangest one, it seems to be unaffected by a complete format.
the format finishes, i can then open up the card (which now shows as empty) from the computer and move files to it, so i eject it and remount it and low and behold everything's there again except for the files i put on after the format.
i don't know what to do as i can't really do much without an SD card =/
anyone got any ideas?
same. mine's been corrupt for a while now with reformat only making it work for a few hours/days.
i'm not sure if this is the crappy card that came with it or the g1's fault...has there been many cases of this?
i'm just buying an 8gb microsd from microcenter for $20 in the next week...i'll deal with my current one until then.
Just buy a new one, its not like they're expensive.
My brand new 8 GB Kingston MicroSD(HC) simply refused to cooperate - The G1 never saw anything I wrote to it on my computer - the computer never saw anything saved by the camera to the microSD. To boot, it even only reported as < 500 MB on the G1. Using the HP USB mem tool (http://files.extremeoverclocking.com/file.php?f=197) I came to the point where the G1 saw 4 GB, but still no way to transfer anything to or from the computer.
Finally, I found this http://rivviepop.wordpress.com/2008/11/11/fix-your-g1-android-messed-up-sd-card/ (requires Linux) that solved the situation. Now both my computer and G1 sees all of the card, and what's on it.Phew!
/Mats
Hi All,
I've searched the forums and I'm unable to find a resolution to my problem.
I'm having horribly slow transfer speeds from the computer to my Atrix internal SD card. I am transferring about 7GB of music from my 64-bit Win7 PC and status says about 4-hours. Used to only take a few minutes on my Captivate.
I've tried formatting the internal card, re-flashing back to stock, different USB ports on the PC, etc all without any luck.
Any ideas before I completely tear my hair out?
Thanks in advance.
EDIT: When the internal SD gets mounted, Windows is slow to find the drive and list its contents. The 2GB external that I have in the phone comes right up.
Wow. No idea. Iwas quite surprised at how fast toshiba emmc is. What speeds are you getting btw? Oh, i do know one thing possibly. Do you transfer files a lot? Flash memory has a limited life, though many of us never see flash die or start to die. But if you do these types large file tansfers, 7gb often, youre using up write cycles much quicker. Also, the folder youre transferring to is about 12 gigs right? Say you have 4 gigs of stuff in their already, and youre trying to put 7 gigs in, more than likely youre transfer speed will be slowed down. You need space to actually to fill stuff up, and the more space, the faster you can fill it up. I wish i could be a little more detailed. I know about this from solid state drives, and the concept is basically the same, but works a little different. I dont know if that is your problem though.
I voided my warranty.
n7slc said:
Hi All,
I've searched the forums and I'm unable to find a resolution to my problem.
I'm having horribly slow transfer speeds from the computer to my Atrix internal SD card. I am transferring about 7GB of music from my 64-bit Win7 PC and status says about 4-hours. Used to only take a few minutes on my Captivate.
I've tried formatting the internal card, re-flashing back to stock, different USB ports on the PC, etc all without any luck.
Any ideas before I completely tear my hair out?
Thanks in advance.
EDIT: When the internal SD gets mounted, Windows is slow to find the drive and list its contents. The 2GB external that I have in the phone comes right up.
Click to expand...
Click to collapse
Take the SD card out of the phone and put in the adapter. Try measuring speeds via adapter. Your SC card might be dying.
His internal card.
I voided my warranty.
Just thought I'd throw this out there, when you format an SD card it asks you for the amount of "bits" you want to format it with. I would research which number is best suited for your particular SD card depending on how big it is. Cause the standard number it automatically inserts may not be the best.
edit: ignore post. For some reason when I read it, my eyes saw external SD card instead of internal. Derp and Derp.
Which of the four (well, three) USB modes are you using to do the transfer?
.......right in the middle of a super demanding day, the message "damaged SD Card / Reformat" appeared on my Epic, when I least expected it (inopportune is the word)............ changing firmware is never without its more interesting moments, + this may or may not be a symptom (went froyo to gingerbread), however,........... am sharing this post to the Epic community, as i sense this to be an important enough issue...........no one really knows the specific cause of sd card corruption + failure: it's variable + always somewhat circumstantial (ie, saw it mentioned elsewhere that overheating from an overclocked cpu could cause damage as well)...................so, moving forward I simply want to contribute as a brief description, here, how i was able to recover (most) of the files from my 'damaged micro sd card:'
First, when i saw 'damaged sd card / format card' on the phone, when it became possible 4 me to do so many hours later, instead of 'formatting' I replaced the damaged card for a new one (pny 16gb sdhc class 10)...booted the phone everything was fine (15.91gb space available)........as expected, no files in the SD Card......................next:
(1) placed 'damaged' sd card into the reader that came w/ the device, and mounted to pc, selected the drive (followed by confirmation beep 'device detected' sound, then the language: 'd:\ not accessible. The file or directory is corrupted and unreadable' came on the screen..........went to RUN and typed CMD........from new window, I typed Chkdsk d: /r and the PC began reading the contents of the damaged SD card (most of the android zip files etcetera were there, as were a number of files w/ no content) + next i typed 'exit' (no quotations, just the letters) to return to the windows desktop.......OK, so now the only files missing are the pix + video mov's (far as I can remember).
..........(2) next, to recover pix + video, from the pc desktop i opened ZARecovery (if you do not already have it go to Data Recovery Software, Solutions, Tutorials, Forum - ZAR Data Recovery and download the free recovery program from that site).
.............(3) from the ZARrecovery main page, selected sd card as device, selected 'next', selected 'root' folder for all files that ZAR was able to detect as recoverable, entered destination folder name (for transfer of recovered pix + video to PC....note: NEVER to sd card itself!), + lastly, selected 'start copying selected files'.........and that was it, closed ZAR + began viewing the content of the recovery folder to get an assessment of what had actually been recovered, and what had been lost.................fortunately 4 me, the loss was minimal, as I tend to create backups (Nandroids, every half year; pic, videos, email attachments = pretty regularly).
Hope this helps those of you that have been experiencing microSD Card damage (from whatever source).
Remember, + not to speak to the Choir, but can not to overstate this: BACKUP............. BACKUP............. BACKUP.............BACKUP
MODS STICKY THIS!!!!
Sent from my SPH-D700 using xda premium
I see you took my advice, nice.
PLEASE STICKY!
Sent from my SPH-D700 using XDA App
Thank you to the Mod that stickied this. Sonarchist...you have arrived!
sonarchist said:
.......fortunately 4 me, the loss was minimal, as I tend to create backups (Nandroids, every half year; pic, videos, email attachments = pretty regularly).
Hope this helps those of you that have been experiencing microSD Card damage (from whatever source).
Remember, + not to speak to the Choir, but can not to overstate this: BACKUP............. BACKUP............. BACKUP.............BACKUP
Click to expand...
Click to collapse
Yikes! I make nandroids before I do anything I consider major like updating Superuser when the reviews are sketchy, or when I do something like apply a new patch, a new tweak, or anything that I think could give me trouble. As I have my phone tuned absolutely perfect, where I want to bring my phone back to normal with a minimum of work.
I guess I am lazy. I nandroid every 3 to 7 days.
mouseglider said:
I nandroid every 3 to 7 days.
Click to expand...
Click to collapse
.....you're awesome!.......my personal history, when I find stability, is to live w/ a perfect set-up for as long as i can surf that wave (hence: nandroid every 6 mo's)........but this is being idealistic.........for example, when testing a beta ROM, an average of at least 6-9 nandroids in the sd card thru several versions of the beta, and at least 3 in the Nandroid Folder in the pc (which is altogether another story: visualizing + creating a pc backup that is operative in a worse-case scenario.)
sonarchist said:
.....you're awesome!.......my personal history, when I find stability, is to live w/ a perfect set-up for as long as i can surf that wave (hence: nandroid every 6 mo's)........but this is being idealistic.........for example, when testing a beta ROM, an average of at least 6-9 nandroids in the sd card thru several versions of the beta, and at least 3 in the Nandroid Folder in the pc (which is altogether another story: visualizing + creating a pc backup that is operative in a worse-case scenario.)
Click to expand...
Click to collapse
I should add that one of the reason I nandroid so often, is that if I do it every 3 to 4 months (on my wife's epic because she travels) when she gets back, I have a ton of updates to catch up on - mine of course is always up to date.
mouseglider said:
I should add that one of the reason I nandroid so often, is that if I do it every 3 to 4 months (on my wife's epic because she travels) when she gets back, I have a ton of updates to catch up on - mine of course is always up to date.
Click to expand...
Click to collapse
Haha! Same with me and my GFs...she never updates! So if your sd card crashes you will seriously need this tutorial since all your nandroids are there.
Awesome info. Thanks for sharing!
kennyglass123 said:
Haha! Same with me and my GFs...she never updates! So if your sd card crashes you will seriously need this tutorial since all your nandroids are there.
Click to expand...
Click to collapse
I am so paranoid about sd crashes and corruption because I have had my share when upgrading to the next bigger card (had a 2,4,8,16, and now 32gb in each epic) that I sync my epic cards to my PC on two separate drives for both my wife and myself (my PC has three physical (not virtual)l hard drives C, D, E) every 3 to 4 weeks. So for her, I am pretty safe except for those long updates in between her trips home. I feel pretty safe in case I do something stupid, which I do from time to time.
I actually tried to convince her to get an iPhone, because I think there would be less updates than Android, but she won't give up the physical KB. Not that I don't like updates, but I set her epic to be a 98% clone of mine, so we each have a lot of apps and each app is eventually updated and often!
mouseglider said:
I should add that one of the reason I nandroid so often, is that if I do it every 3 to 4 months (on my wife's epic because she travels) when she gets back, I have a ton of updates to catch up on - mine of course is always up to date.
Click to expand...
Click to collapse
NITDH.......you don't want that!........(nandroid-in-the-dog-house)....lol
.........arrival of the backup evangelists!
kennyglass123 said:
Thank you to the Mod that stickied this. Sonarchist...you have arrived!
Click to expand...
Click to collapse
........a hi-5 to the Mods for Sticky'ing this: thanks guys!....... props to kennyglass123 + xopher.hunter for suggesting it to 'em.............nothing more stressful than going down that gopher hole attempting to recover data, it's no picnic!...........so am hopeful that we can salvage some valuable data + find ways to hinder that inevitable moment when the sd card reads 0%.............as they say, there's many more ways than 1 to skin a grape, or in this case, a corrupt microSD Card.
There is an undelete beta app on the market. Check it out.
Also, check out testdisk for when the partition table is fried.
Also, recuva. Pretty awesome, by the makers of ccleaner.
sent from my always aosp epic
mouseglider said:
I am so paranoid about sd crashes and corruption because I have had my share when upgrading to the next bigger card (had a 2,4,8,16, and now 32gb in each epic) that I sync my epic cards to my PC on two separate drives for both my wife and myself (my PC has three physical (not virtual)l hard drives C, D, E) every 3 to 4 weeks. So for her, I am pretty safe except for those long updates in between her trips home. I feel pretty safe in case I do something stupid, which I do from time to time.
I actually tried to convince her to get an iPhone, because I think there would be less updates than Android, but she won't give up the physical KB. Not that I don't like updates, but I set her epic to be a 98% clone of mine, so we each have a lot of apps and each app is eventually updated and often!
Click to expand...
Click to collapse
Gr8 backup regimen..........'best practices' worthy.........given the 1,000 cumulative hrs leading to your perfect setup, worth all the special handling to keep devices singing!
props on the recovery
Mine took a dump today but it may be a total failure. I just got home and this is what the preliminary tests show. I would appreciate any input.
chkdsk
The type of the file system is RAW.
CHKDSK is not available for RAW drives.
testdisk
Capacity incorrectly showed at 8225kb/8032kb (16gb card)
Analyze feature reports a Partition Rear Error
As a sidenote, the TitaniumBackup sync-to-Dropbox feature has probably saved my butt as far as apps/data goes. I highly suggest using it to protect against dead cards.
Sadly SD cards and USB sticks are very unreliable when it comes to data. They are easily damage and anything slight can cause them to be corrupted.
This is a great guide, glad you were able to restore your data!
Most data in flash type memory cards (excepting physical cracks in the microSD Card housing + damage to the memory chip itself) can be recovered w/ several DIY software programs available on the android market..........ugothkd shared a few of these, several posts up.........in the event that there is NO BACKUP available to you + having exhausted all personal DIY recovery avenues, there are still ways to step-up the process and very likely recover some of your data..........am quoting the following language from Recoverfab (maker of enterprise flash readers to the trade):
'In general, there are two reasons why the data on memory flash devices (cards, USB-sticks, SSD) becomes inaccessible.
Logical damage prevents access to the data/pictures on the drive, but the drive is still physically recognized by the computer operating system. In this case some specialized types of recovery software can help. Sometimes free recovery tools like Zero Assumption Recovery can also solve this problem.
Physical damage causes the drive to be unrecognized by the computer's operating system, making it impossible to access the contents of the flash-memory chip. This type of damage happens in more than 80% of all known cases. These are most frequently caused by electrical problems that lead to physical damage. Flash devices consist of a memory chip and a controller. The controller writes and reads the data from the memory chip. In most cases, recovery is possible from a flash device with a damaged controller and mostly undamaged memory chips.
Formatting is required? The controller of the memory card is not in the position to inform the PC operating system about the characteristics of the memory card. Therefore, the PC assumes that the memory card is not formatted and requests formatting. One might think that the memory card problems would be solved by formatting, but unfortunately it does not work due to the damaged controller. Instead, the computer will communicate that formatting is not possible. Such an error is a clear indicator that no kind of software (including special formatting or rescue software!!) will be able to access the memory card.
.....Recovery Process: If the flash storage device is not recognized in the computer or it is impossible to access the data on it, there is only one way to get the data: unsolder the memory chip from the printed circuit board and directly access the raw data with a programmable chip reader.' <end quote>
OK......that was a long quote!.....worth repeating, if only to begin to address the sort of things that can damage / corrupt SD Cards (+ also to give those of you that really want to recover your lost data super badly some HOPE).
Heat, liquid, dust, some of the things that WILL damage your SD Card (numerous other things can corrupt your data as well) .....then you hear cases of individuals that have NEVER HAD ANY DAMAGE WHATSOEVER...........some burnin' Q's: is the fragile nature of the card itself doomed to failure? ...If the card is going to fail eventually, what kind of data would you be willing to risk storing in there?...... if the data is that important to you, would you be willing to make a 'twin' copy? (twin SD Card could be swapped quickly in case of ER) ..... + lastly, has anyone here found a fail-safe or fairly sound way to run voluminous or frequent data transfers between your device's SD Card + pc?
sonarchist said:
Most data in flash type memory cards............. if the data is that important to you, would you be willing to make a 'twin' copy? (twin SD Card could be swapped quickly in case of ER) ..... + lastly, has anyone here found a fail-safe or fairly sound way to run voluminous or frequent data transfers between your device's SD Card + pc?
Click to expand...
Click to collapse
Yup, I have a spare twin identical card Lexar 32gb class 10 waiting in the wings as a backup.
I use a program that can transfer and/or sync in many different ways my card to my PC, which I do every three or four weeks. It is called FolderMatch v3.44. I am sure there is a newer version out, but the one I have does the job
I simply plug my USB cable into my PC and the other end into my epic and simply choose synchronize, then chose make left folder (my PC) to be the same as the right folder (my epic) - depending on how many files you are syncing determines the speed of the sync. Works good for me!
quick99si said:
Mine took a dump today but it may be a total failure. I just got home and this is what the preliminary tests show. I would appreciate any input.
chkdsk
The type of the file system is RAW.
CHKDSK is not available for RAW drives.
testdisk
Capacity incorrectly showed at 8225kb/8032kb (16gb card)
Analyze feature reports a Partition Rear Error
As a sidenote, the TitaniumBackup sync-to-Dropbox feature has probably saved my butt as far as apps/data goes. I highly suggest using it to protect against dead cards.
Click to expand...
Click to collapse
ZAR has an 'unformat' option for Raw File Systems, you may want to explore if there is data remaining in your SD Card that you may want to recover (there's a brief tutorial posted on their website) ........ here's a glimpse:
"Unformat is the process of data recovery from a storage device (which can be a hard drive, a camera memory card, an USB pen drive) that was formatted.
The step-by-step tutorial below describes the procedure to recover data when the drive was accidentally formatted and you want to unformat the drive Windows reports "raw filesystem", or the drive is "not formatted" <end quote>
The above makes reference to a specific type of recovery (accidental format of a drive, as an example), but the application will recover from a number of file types + systems............worth checking it out.
*edit* as another example, 'accidental format of a drive' can also refer to split-second decisions we make when we guickly hit 'reformat sd card' on our device the very first time we ever encounter a 'corrupted external card / reformat?' type of message........in the moment, life goes on + it's only later that we begin to think of the lost data..................however, chances are pretty good that the data is recoverable (files are still inside the 'reformatted' sd card, only unreadable, ie RAW).