How To Protect Your Memory Card

[travismcgee]

Hi All,

 

I just got back from a class on Digital Archiving at my local camera store and the instructor gave us four tips for

protecting your memory cards from corruption. Here they are, and you can draw your own conclusions.

 

Cheers,

Dave

 

 

1. Format the card IN THE CAMERA every time after you download the images to your computer. In fact, format it

three times. (His explanation of why to format three times had more to do with security than reliability, but that�s

what he said to do.)

 

2. Never take the last picture on the card. When the counter gets low, stop with one or two images remaining and

switch cards.

 

3. Never erase on the fly. Wait until the images are in your computer to delete the bad ones. Shooting, erasing,

shooting, erasing can confuse the card.

 

4. Never pull a card out before the camera is done writing to it and never let the battery die during a read/write

operation.

[bobatkins]

Well, I do #2 and #3 regularly and I've never had a single corruption problem with my cards.

 

I do format (once) before use. Mutiple formatting won't really do much.

 

It is a good idea not to remove a card (or let the power fail) while it's being written to (or read from).

[johnson_d.]

I'm a regular violator of #1, #2 and #3 and have never had a problem, ever. I would like to hear a technical explanation of why these three are deemed important. My guess is that there isn't one.

[dave_hoffmann]

I format each time in camera (just once) after downloading to computer.

[zml]

Yeah, and you'll need a black cat, crossroads and a devil to sell your soul to :-))) <br>Seriously, with all due respect

to the instructor, but, with the exception of 4, it is all nonsense. Of course it is up to you to use whatever voodo feels

good, but there is absolutely no reason to format the card every time or not to erase pics on the fly. Yeah, the file

allocation table does get corrupted, but it happens very infrequently and/or regardless of the in-camera formatting,

erasing, etc. If you have a CF card corruption problem even once, have your camera checked and/or get a new

card. The "three times is a charm" in number 1 is especially laughable, because - unles you perform low-level

format - all that in-camera formatting does is delete file management data. So once, twice, 3, 4 or 15 times makes

no difference... Most CF card failures I know of are due to physical stress or improper insertion (bent/broken pins)

and that's why I simply connect my cameras to the 'puter to D/L images instead of removing the card each time. (Or

use a reader if the card is already not in the camera.)

[bryantan]

#1 is just pure humbug. Nothing but a low-level format erases any information on the card.

[digitmstr]

I format ONCE. Never had a problem with that. Also, I do delete pictures I don't like and I regularly shoot until I get the FULL message. Again, never a problem.

 

As for pulling the card while the camera is writing to it...who would do that?

[--aa]

#1 is probably not true. Most OS's support fast format and I would assume that the camera only does 'fast format' when formatting the card. The fast format only resets an index and does not erase the actuall images. (It only marks space for the camera as available), and formatting it more then once gains nothing.

 

Perhaps the instructor is used to working with a particular camera which had issues with storage managment.

[john_g10]

Only #4 makes sense to me.

[jeffrey_blake_adams]

Y risk it, its always GREAT when ppl pass along "Best Practices" it up to you if you do it every time, or most of the time or not at all. J

[baivab]

I am from technical background and have dealt with many types of storage media. Format/re-format does not help. Quick format

by camera removes from disk only certain information, which might be called as pointers to the data. The data sector or cylinder

data is not touched. In fact, by repeatedly re-formatting the disk, you're effectively read/writing that critical portion of the disk which

is the heart. Thus, it's actually a BAD THING TO DO. Now, let's look at the rest:

<br> Item No.2 : Would be relevant if the block sizing of the card has been configured incorrectly to cause an overwrite of an

existing partition. These happened in VERY OLD disks, not cards, etc.

<br> Item No.3: No issues, if erased on the fly.

<br><br> Here's my list, which I have full logical reasons and can vouch for it:

<br> 1. If you're erasing @ camera, when it's connected to the computer, you can try to defragment it. If you don't know about

defragmentation - read it. Also, it's hardly required every time and computer will say so.

<br> 2. Never eject the USB directly but use the "Safely remove..." option in task-bar.

<br> I don't use a Mac or a Linux, but I guess it'll be more or less the same.

<br> Check for firm-wire updates for the CAMERA DRIVER and CAMERA , regularly.

There's a school of thought saying the "Safely remove .." option in un-necessary, but I have found enough cases to warrant

otherwise.

<br> Hope this helps!

[beauh44]

<I>In fact, by repeatedly re-formatting the disk, you're effectively read/writing that critical portion of the disk which is the

heart.</i><P>

 

But it's not a "disk". It's solid-state. (Unless you're still using something like the old IBM Microdrive) <P>

 

I see no point in multiple, in-camera, formats; one should do fine. I do think formatting - as opposed to erasing - after

copying your images, is preferable because it re-writes the FAT table on the card and helps prevent file fragmentation.<P>

[sarah_fox]

Thank you, everyone (especially Baivab), for addressing these oft-mentioned platitudes. I've never had a problem with 1, 2, or 3 either, but much of the talk I've heard elsewhere has made me (unneccessarily) nervous about my practices. I've only had one corrupted card in my life -- in a very early Oly 1.3MP P&S. However, I don't think I violated any of rules 1-4. I think it was just buggy code in the firmware (which also wouldn't write TIFFs, even though it was supposed to).

[g dan mitchell]

<p><i>1. Format the card IN THE CAMERA every time after you download the images to your computer. In fact, format it three

times. (His explanation of why to format three times had more to do with security than reliability, but that�s what he said

to do.)</i></p>

 

<p>Do format in the camera after each use. But three times?! That sounds bizarre and paranoid. I wouldn't bother.

 

<p><i>2. Never take the last picture on the card. When the counter gets low, stop with one or two images remaining and switch

cards.</i></p>

 

<p>I've filled many cards and never had a problem.

 

<p><i>3. Never erase on the fly. Wait until the images are in your computer to delete the bad ones. Shooting, erasing, shooting,

erasing can confuse the card.</i></p>

 

<p>This should not "confuse the card." I often delete shots after I take them if they are real losers, especially if I'm concerned about space

available on a card. Never had a problem in tens of thousands of frames.

 

<p><i>4. Never pull a card out before the camera is done writing to it and never let the battery die during a read/write operation.</i></p>

 

<p>Good advice.

 

<p>Dan

[zml]

<i>"Safely remove..." option</i><br>This is important only if your computer is WRITING to the storage card, which

(outside of the EOS Utility) shouldn't happen.<br><br><i>But it's not a "disk". It's solid-state. (Unless you're still

using something like the old IBM Microdrive) </i><br>Flash memory has a limited number of write-erase cycles.

OTOH I wouldn't worry about it in practice...<br><br><i>re-writes the FAT table on the card and helps prevent file

fragmentation.</i><br>How exactly does that prevent file fragmentation? If all files are deleted, the FAT entries

reflect that fact and the disk is populated with new data more-less sequentially. Fragmentation occurs when you

delete only some

files thus creating empty/unused space which may or may not be reused in one chunk. If all files are deleted there is

no fragmentation.

[marc_bergman1]

The instructor forgot tip #5.

 

#5. Start the format sequence. Put the camera in a brown paper bag. Wave it over your head and cluck like a chicken.

 

I miss the Dick Van Dyke show.

[abzphotoz]

# 6....make sure your watches hour hand doesn't point to the Southeast while you are simultaneously chewing gum while removing your memory card.

I believe the best way to look at this is to get to the all important bottom line. If someone experiences loss of data on their card it is either because the card itself is cheap or defective. The only thing you can really do to protect yourself is to not use 16 or 32 gb cards. Use a few smaller cards instead so if by chance you happen to get a defective card then at least not all of your images are on 1 card.

[colin_james]

"Never take the last picture on the card. When the counter gets low, stop with one or two images remaining and switch cards."

 

This one came about due to a bug in firmware for some camera models. The indicated number of shots remaining is an estimate based on a calculated "averaged file size" for that particular setup (ISO etc) --- the space remaining on a card may be more than the average file size (hence camera shows 1 shot remaining), but if the data set from the shot taken just happens to be bigger then a situation could arise where the camera had more data to write than was available to store it - (ie the write operation failed unexpectedly) and card corruption occured.

 

Hasn't been an issue for many a year, although prevention of the "issue" was made popular by Scott Kelby in one of his books.

 

Cheers,

 

Colin

[beauh44]

<I>Fragmentation occurs when you delete only some files thus creating empty/unused space which may or may not be

reused in one chunk. If all files are deleted there is no fragmentation.</i><P>

 

Agreed - I didn't word that well. Let me put it this way, if one rarely (or never) formats their card(s) and instead relies

solely on the "delete" method(s), i.e. occasionally marking some files to keep by flagging them read-only in-camera and

deleting the rest, then shooting more, deleting some again and so on 'til a card fills up, well... the files on a card over

time *can* become fragmented and FAT tables can get screwed up - just as they can on a disk. Periodically formatting

the card, in-camera, is just a good idea, imho. I'll sometimes do this to a PC's hard disk - just "splat" it by re-formatting it

and re-install the OS.<P>

 

And while I'm sure cards do have limited write/erase cycles (eh, who doesn't? ;-) I don't think anyone's in danger of

wearing out a "critical portion of the disk which is the heart" while using solid-state cards and that was my point.<P>

 

I still have CF cards I bought 6 or 7 years ago that work fine - I don't use them much because they're too small. But I

attribute it, in part, to my never doing an "erase all" - or marking some files un-eraseable and erasing the rest. Instead,

after copying my files off, I just put the card back in the camera and hit format. So far - knock on wood, big-time - I have

never had a card failure.<P>

 

BTW, I never worry about #2 and #3. If I know I've just shot a dud, I erase it, in-camera to free up the room. And I never

worry about taking the last shot. The last one (#4) is common sense; don't pull a card out while your camera - or

anything else - is writing to it.

[sarah_fox]

Michael wrote: "Safely remove..." option

This is important only if your computer is WRITING to the storage card, which (outside of the EOS Utility) shouldn't happen."

 

Actually this becomes a problem if you have data in a buffer, destined for the CF, that hasn't yet been physically written. When you "safely remove," the process clears the buffers, completes all writes, and generally squares everything away. If you're doing file manipulation (think: changes to the FAT), and the final changes to the FAT haven't yet been written, I imagine you could be in a lot of trouble by just yanking the card.

[jim_larson1]

I have been shooting digital for a number of years (2002?). I have only ever formatted cards twice. In one case, the card (not a CF card) was wrecked and formatting did not help.

 

The second time, I had a random problem and a windows format solved it.

 

I have never formatted in the camera. . .even new cards seem to work just fine.

[peza]

If you format only once - you already <u>might</u> reduce your card speed by factor 2 by the cluster misalignment. Read more <a href="http://www.hjreggel.net/cardspeed/cs_calign.html">here</a>. Everything except #4 is total nonsense in my eyes.

[NK Guy]

You know, I thought this sort of advice was handwaving nonsense too. But I have had data loss on two occasions.

 

1) An EOS 10D with a Lexar card.

 

2) An EOS 5D with a Sandisk card.

 

So. The cameras were different, the cards were different. I think the card readers used may have been different.

 

I didn't open the memory door until the camera had finished writing and the red light was off and I'd powered down the camera.

 

Yet in both cases I had corruption on the card resulting in catalogue damage. I had to use data recovery tools to retrieve the bulk of the

photos from the cards.

 

The only connection between the two events is that in both cases I erased photos in-camera a lot, and shot and reshot and deleted

until the cards were full.

 

Last weekend I had a somewhat similar situation with a 5D and a 4 GB Sandisk card. I deleted a load of photos and reshot until full.

This time I didn't get any directory damage, but the last photo on the card was corrupt and unreadable.

 

So I'm not sure that these claims are entirely fantasy.