32GB SDHC card problems...


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OK, I created a new page on our wiki. Can you guys add your cards?


pandorawiki: SDHC compatibility list
The problem with such kind of list is that the characteristics of some brands of SD cards may be different depending on, amongst other things, which brand it is, where you bought it, and when you bought it. [1]


The list could at least need an additional data field that tells the reader whether or not it is verified that a brand's innards have rather constant characteristics across cards. However, this information is usually hard to get / find out [1], so we might end up with very little reliable information. But at least in my humble opinion that's better than having loads of information of questionable usefulness.


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[1] http://boards.openpandora.org/index.php?/topic/1046-whos-is-going-run-the-os-from-the-sd-card/page__view__findpost__p__19461

OK, so we need to add an appropriate disclaimer there. For now it looks like nobody has a working 32GB or 64GB card.


For example, based on your lenghty explanations in [1] I started to look for 32GB Sandisk Eextreme class 6, but apparently it has never been produced:


* class 6 sandisk extreme (max 16GB): http://www.sandisk.com/products/camcorder/sandisk-extreme-hd-video-sdhc-cards


* class 10 sandisk extreme (max 32GB): http://www.sandisk.com/products/imaging/sandisk-extreme-sdhc-cards-


From what Prometheus says class 10 are more likely to fail, so I would rather prefer to stay off. There is however some chance that I could test this card before buying it - I'll need to talk with my friend in the computer store.


Also, from what you say "Sandisk Ultra" are not going to work? I ask, becuase the 64GB card exists only in this one flavour:


* class 4 sandisk ultra, 64GB: http://www.sandisk.com/products/dslr/sandisk-ultra-sdxc-cards


Also I looked for Panasonic, but they are not sold in Europe at all - no chance to get one.


I would have never suspected that buying a ext2/3/4 working 32GB card would be such a PITA. Could you help me a bit with this? (I already RMA-ed kingston 32GB (red), but in fact it's just lost money for me - now it turns out that it was broken "by design")


What should I do?


* try a 32GB class 10 sandisk extreme?


* settle for 16GB class 6 (safest bet)?


* risk 64GB ultra?


There are also "Extreme III" variants, which nobody tried yet, apparently. But they seem to be faster ones, therefore more eligible to not working with ext2?


other options?

My 64GB SDXC card WORKS in the PC with ext2/ext3/ext4 so don't worry, you didn't bought something broken "by design" at all. A bit of research (ie: updating the SD slot drivers in the next hotfix) should fix this. I have bought an USB SD reader that seems to work without doint anything special but I have not yet tested it well on the pandora, it was just 2 euro, you can try something similar too. I will tell you if I get read/write errors there too on monday or so.
 
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From what Prometheus says class 10 are more likely to fail, so I would rather prefer to stay off. There is however some chance that I could test this card before buying it - I'll need to talk with my friend in the computer store.
That's seriously not what I said... ;)


I said that I know that some people using Class 6 cards or Class 10 cards, including myself (I'm using a Class 6 32GB card from Verbatim), have reported problems with corruption and suchlike (from what I recall, this has affected cards formatted as FAT32, ext2, and ext3). That's all I said. ;)
 
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I've got a 32GB class 4 card from Kingston, no problems, formatted as FAT.


Now I feel glad I didn't spring for a faster card. :p
 
From what Prometheus says class 10 are more likely to fail, so I would rather prefer to stay off [a SanDisk extreme class 10 card, remark].

(...)


There are also "Extreme III" variants, which nobody tried yet, apparently. But they seem to be faster ones, therefore more eligible to not working with ext2?
If you read her statement again carefully you can see that she just presented symptoms and correlations while not implying a definite cause (instead suggesting a possible cause): "[...] several people, [...] are encountering problems using fast cards (Class 6 and Class 10) with the Pandora at the moment, and in some cases this extends to using particular file-systems on those cards" [1].


So this statement does not necessarily mean that class 10 cards generally have problems with ext2. At least from my non-representative experience, it's very unlikely that there's a causal connection between "high speed class" and "file system problems" (which doesn't mean that there might not be a connection - it's simply unknown to us here at this point). Instead, I guess this might be a problem in either the Pandoras software or (*gasp*) its hardware.


That being said, as Prometheus said there ARE indications that the combination of /some/ higher class (class 6 as well as class 10) SD cards with a (particular kind of?) Pandora does lead to problems. While there are other factors that are not absolutely clear (which, amongst others, may include that lower class SD cards may have similar problems but the low class rating makes users believe that the cards simply can't stand a lot of stress; or that it's possible that the increased number of problem reports covering this SD card problem is caused by selective perception), it seems likely that parts of the interaction between some kinds of SD cards and a (particular kind of?) Pandora is causing this particular kind of problem ("some kinds of SD cards" /might/ mean higher class (class 6 and class 10) SD cards, but may also mean some other kind of SD card that coincidentally correlates to "higher class SD card")

Also, from what you say "Sandisk Ultra" are not going to work?
You mean because the changelog says that I replaced "SanDisk \"Ultra\"" with "SanDisk \"Extreme\""? If so, then no - I had simply made a mistake. I didn't mean to imply anything about SanDisk Ultra, it's simply that I would have written SanDisk Extreme in the first place hadn't I mixed up the brands.

There are also "Extreme III" variants, which nobody tried yet, apparently. But they seem to be faster ones, therefore more eligible to not working with ext2?
By "SanDisk \"Extreme\"" I referred to all SD cards of the SanDisk Extreme line - it's not the immediate speed that makes the "Extreme" line from SanDisk (no matter what iteration), as well as some other brands of better SD cards, different from average SD cards; basically it's how well they handle stress (physical stress, excessive small "random" writes, and similar things).

Also I looked for Panasonic, but they are not sold in Europe at all - no chance to get one.
At least in Germany you can get them in "Gold" and "Silver" flavors in bigger electronics stores, typically somewhere at the digital camera section (even if other places of the store are full of SanDisk). amazon.de also has them, but I have no idea if you can order them from amazon when you're in another country. Quite a few photographers are using Panasonic cards, so maybe some stores around you that have good digital cameras will have them.

I would have never suspected that buying a ext2/3/4 working 32GB card would be such a PITA. Could you help me a bit with this?
People may be able to give non-representative experience reports, but unless we collect quite a few of them and correctly use comparable benchmarks and testing methods (which, as you now know, is very easy to screw up given the complexity of the situation), you can only make an educated guess. As you know, I already did that, and even though I did some research on SD cards in general, my suggestion of cards that I typically use for stress-laden situations may currently not work very well for the Pandora if there are indeed problems with higher class SD cards. Someone has to find out the exact cause for these problems (that would be the best solution). Depending on when and if that happens, and also depending on what the actual cause is, you will be better off with either a slow or a fast card.


This is the kind of situation that makes me wish that "luck" wasn't just a word for not yet analyzable occurrences.


edit-27mar2011-0458GMT+1: Yay, the thread has a second page. Hi second page!


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Version history:

29mar2011-2115GMT+2:

  • Minor changes.
 
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That being said, as Prometheus said there ARE indications that the combination of /some/ higher class (class 6 and class 10) SD cards and a (particular kind of?) Pandora does lead to problems.
I'm not sure if I've been misread or if I'm misreading you here, so either way please pardon me, but I have no idea about combinations of these cards. I don't have access to a Class 10 one - I just said that I've heard separate reports of a few instances of problems with Class 6 as well as Class 10. :p


I'm no expert in this regard - I specialise in warning about fakes, really - it was just something I've noticed a few reports of (and of which I made one myself :lol: ). The entirety of what I've observed on this front is that a small number of folks with cards specifically marketed as being high speed, have encountered some issues. There are most likely some different (possibly related, possibly not) issues at play here.
 
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I'm using a 32GB class 10 Kingston, which I presume is formatted fat32 since I haven't reformatted it, and I've been having corruption problems.
 
I'm using a pair of 32gb Patriot Class 10 cards, I've yet to experience any FS corruption issues yet, but I'm also only using FAT32 for now. I'll see if I can get some time to test this out later.


Also this question is slightly off-topic, but can't you set EXT4 to be journal-less? It should perform better than EXT2.
 
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Also this question is slightly off-topic, but can't you set EXT4 to be journal-less? It should perform better than EXT2.
There's just one small Problem: You can't boot from it, ext4 needs an extra driver. ext3 can be used with an ext2 driver, you just lose the journaling.
 
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This is the kind of situation that makes me wish that "luck" wasn't just a word for not yet analyzable occurrences.


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[1]
(sorry for that large snip ;) )

Thank you for all the valuable input. Now I have ordered "SanDisk class 4 32GB Ultra II (15 MB/s)". And I'll report shortly :)


For now, I guess, the only thing that we can do is to collect as much as possible information in SDHC compatibility list. Even though, we know that this information will be ambigious, eventually it will help us to locate the real problem. If it's in pandora's software or hardware (eek: then it will be stuff to correct in pandora2) or is it card's hardware.
 
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To add to the data points: Transcend 32Gb Class 10, same problems.
 
Do we have a good reproducable test?


It woudl be cool to make a pnd that just does a few file-creates-and-md5sums tests and reports if SD seems working or not. For 1) test we can all use, repeatably and easy, and 2) Peace of mind :)


I just picked up two 32GB class 10 Kingstons ($65ea or something, CDN) .. expensive bastards; copied 8GB of stuff onto one so far from my old full 8GB SD, and seems to work fine.. but I've not pushed it hardly at all. Reading movies from it, okay.


FAT32 mind you .. I tend to always use FAt32 on SD, for maximum compat across OSes.


(Also, ext2/3 are never good on SD imho .. too fragile; a crash in the wrong time, and poof, all corrupt.)


jeff
 
Do we have a good reproducable test?

During testing I narrowed the problems to a very short reproducible test (card in left slot):



Code:
df                              # check if your partition, that you want to test, is mounted

umount /dev/mmcblk0p1           # umount that partition

df                              # read what "d"isk"f"ree has to say, to make sure it is not mounted

mkfs.ext2 /dev/mmcblk0p1        # format

e2fsck -C 0 -fy /dev/mmcblk0p1  # check if format was OK

If e2fsck runs fine, then it should be OK.


You must be carful that your partition is not mounted. It is very annoying, but something in the UI (xfce, or sth else) is insisting on mounting everything it sees. So before formatting make sure to umount, after formatting and before fsck - make sure again that it is not mounted.


If this simple test could not pass, nothing else was working for me. I tried two 32GB cards up till now. Now I'm waiting to get my hands on third one.

It woudl be cool to make a pnd that just does a few file-creates-and-md5sums tests and reports if SD seems working or not. For 1) test we can all use, repeatably and easy, and 2) Peace of mind :)

I just picked up two 32GB class 10 Kingstons ($65ea or something, CDN) .. expensive bastards; copied 8GB of stuff onto one so far from my old full 8GB SD, and seems to work fine.. but I've not pushed it hardly at all. Reading movies from it, okay.


FAT32 mind you .. I tend to always use FAt32 on SD, for maximum compat across OSes.


(Also, ext2/3 are never good on SD imho .. too fragile; a crash in the wrong time, and poof, all corrupt.)


jeff

FAT will always work for you, unless the card is really faulty. I need an ext2/3/4 capable card, because I plan to run full-blown linux from it. FAT isn't enough. Or maybe there is some other SDHC-flash-friendly filesystem, that has all capabilities of a POSIX filesystem? I never heard about one, but maybe I missed something..
 
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Do we have a good reproducable test?


It woudl be cool to make a pnd that just does a few file-creates-and-md5sums tests and reports if SD seems working or not. For 1) test we can all use, repeatably and easy, and 2) Peace of mind :)


jeff

Wouldn't a PND'ed version of F3 with some zenity scripts do the job?
 
yes it would; my point was.. fishing for someone to create a pnd with test utils on it and easy to use 'go test!' option,without me building it ;)


cosurgi -- I've been cheating, and using loopback filesystem files on FAT32 to do my alien fs work; I'm using some pretty obscure filesystems (minix ftw :) and such, so just toss them all as files onto the FAT32; however, that can limit filesize.


So I often end up with NTFS format USB or SD media, with loopbacks on there; little goofy, but pretty solid even though devices crashes :p (NTFS and FAT, for all their flaws, survive things like that pretty well, whereas in my experience, ext2/3/4 do not.)


I did a lot of ext2 on SD in early pandora days and had a lot of issues (but we also had SD driver bugs which casued most of it); with my re-installing firmware several times a night (or dd'ing it, to avoid the first boot) and coupled with SD driver that ate my SDs, I just got a overly bad taste in the mouth .. so that colours my thoughts too much perhaps.


jeff
 
Do we have a good reproducable test?
Unfortunately not. :( If we did, I would have submitted the issue I'm having with my Class 6 32GB card (formatted as FAT32) to the bug-tracker already. I'm pretty sure "Randomly corrupts the working copy of my Mega Man novel when I save it, but not always." isn't enough info! :lol:
 
Do we have a good reproducable test?
Unfortunately not. :( If we did, I would have submitted the issue I'm having with my Class 6 32GB card (formatted as FAT32) to the bug-tracker already. I'm pretty sure "Randomly corrupts the working copy of my Mega Man novel when I save it, but not always." isn't enough info! :lol:
I am pretty sure that my method, two posts above, is pretty reproducible, but it destroys your whole data. So be careful...
 
OK, so we need to add an appropriate disclaimer there. For now it looks like nobody has a working 32GB or 64GB card.

Untrue, I have stated on the other forum that I have no issues using a Transcend 32G Class 10 card. I also have a HP branded 16GB card that is totally cool with the Pandora. I have one AData 16GB card that will not work in any format other than FAT or NTFS.
 
The best reproducible test I can think of is take an SD card with several GB of data on it, copy everything to a class 6/10, and see what works. It's also worth noting that when I tried to backup the contents of my SD card to my Windows 7 computer, before I knew the data was corrupted, the Windows file manager could tell which SNES ROMs (*.smc) on the card were corrupted, but none of the other corrupted files.
 
It's also worth noting that when I tried to backup the contents of my SD card to my Windows 7 computer, before I knew the data was corrupted, the Windows file manager could tell which SNES ROMs (*.smc) on the card were corrupted, but none of the other corrupted files.
I would be careful with damaged filesystems on Windows, I have an USB stick which once had a damaged FAT32 filesystem, and if I tried to delete the corrupted files it crashed XP really hard with a BSOD, absolutely reproducible :lol: On Linux I had no problems, I even got a very nice and kinda funny error message when trying to delete a 'looped' folder later on, it's a shame I didn't try what Windows would have done before formatting it (yes, the Stick itself is screwed and corrupts things when not being plugged in for some time, I'm using it for the Debian ARM system running on my Seagate DockStar now)
 
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