I was trying to understand what are the causes of the problem. My system is using the sd card to write and delete data (.jpeg, video) (24/7), it maintain a couple of blocks up to 1GB of free space. Then, suddenly it reported the said errors and now it reported “sdf: unknown partition table”.
Could you guys give me some expert advise regarding with the said issue?.
SD cards have a limited number of write cycles (I heard 100,000 write
cycles) before they wear out. When you say you're recording video 24/7,
how many cycles would that be?
Thank you for the discussion. Are there any online resources for SD card performance, writes longevity, MTBF, & what are Class ratings about? It appears the B-B is somewhat sensitive to SD Cards. Here’s the Wikipedia SD Card page… http://en.wikipedia.org/wiki/Sd_card
I’ve seeing different SD Card issues in the list. Are there any emerging patterns? If so then it should be possible to devise a diagnostic procedure that you can publish. That might help users DIY & reduce the repeating the same responses.
I’m having read problems of an original from the box B-B xM S/N: 0111xM400. The SD Card will not read in either of my laptops. I understand there is a FAT partition on it.
Class ratings are generally useless for embedded Linux use. They're a
decent reference point if you're buying for use in a digital camera /
camcorder, but if you're doing small writes (less than 1 MB in size),
they don't mean much. A better metric is number of simultaneous open
erase blocks (1 is horrible, 5 is OK, more is ideal), but that's never
printed on the packaging (or in the marketing material).
Partition alignment to the underlying flash also can matter. Using the
alignment provided with 255 heads and 63 sectors almost certainly won't
align to the underlying flash.
Thanks, this is the kind of depth I was looking to find. It is a start. I’m looking for Windows tools to inspect the SD card. It does not show when plugged into the SD slot. I’ve tried two laptops. I have a way to try a third and to try another SD card.
You would think however the OS would indicate a the card was at least in the reader even if it is not formatted correctly. Oh wait it’s Windows, I remember HDs not being recognized until at least one partition was created.
I wonder if anything was ever placed on this SD Card. It was packed in the B-B xM box when it arrived.
The card that ships with the board has a small FAT parttion and an EXT3 partition on it. It boots form FAT and runs the kernel using the EXT3 parttion.
I'm not sure how low-level it can go, but TestDisk is an excellent
tool for diagnosing and repairing/recovering disks: http://www.cgsecurity.org/wiki/TestDisk
It has a Windows version, so it's worth a shot. It's a command-line
interface, but it's fairly straightforward.
Sorry, I'm not familiar with Windows tools of this kind.
I'd recommend Joel or Robert's suggestions of TestDisk or using a Linux
live cd. The Linux live cd approach (with a recent Ubuntu, for example)
should auto-mount the SD card when inserted, showing you all the
partitions that are formatted. fdisk could also be used to inspect the
partition table.
The blog seemed informed. I was particularly interested to see the remarks are purchasing. The purchase size and expected negotiating leverage you may or may not have.
Is Mr. Haung located in Taiwan or PRC? One does not want to create issues for people in my replys.
The blog seemed informed. I was particularly interested to see the
remarks are purchasing. The purchase size and expected negotiating
leverage you may or may not have.
Is there any group or entity who conducted a research of the following for the sd card solutions?.
1.1. SD card wear leveling
1.2. Corruption of data
1.3. Early end-of-life
1.4. Other possible cause of sd card failure (Heat or Temperature, lost of power, uncleaned shutdown).
1.5. Writing multiple files at the same time.
1.6. What are the recommendations in order to avoid the problems?.
Is there any group or entity who conducted a research of the following for the sd card solutions?.
1.1. SD card wear leveling
1.2. Corruption of data
1.3. Early end-of-life
1.4. Other possible cause of sd card failure (Heat or Temperature, lost of power, uncleaned shutdown).
1.5. Writing multiple files at the same time.
1.6. What are the recommendations in order to avoid the problems?.
Even if you did a large study across all the SD cards you
can buy today, most of it would not apply in 6 month as
manufacturers are constantly changing and updating sd card
controllers, firmware and the raw NAND chips inside SD cards.
If you are really after reliability, there are "industrial"
grade SD cards available where the manufacturer might
guarantee some card properties.
Is there any group or entity who conducted a research of the following for the sd card solutions?.
1.1. SD card wear leveling
1.2. Corruption of data
1.3. Early end-of-life
1.4. Other possible cause of sd card failure (Heat or Temperature, lost of power, uncleaned shutdown).
There is one important possibility to take into account: the card reader.
I have e.g. a Transcend 8 GB Class 10 card that can't be correctly written on
* eeePC 701 internal reader with Debian Squeeze
* some old external card reader with USB 1 & 2
* a brand new Transcend (!) external SDHC/SDXC card reader with USB 2 & 3
It works perfectly when connected to an OMAP3 CPU. And I can
write it perfectly on the SD reader built into an UMTS/USB stick.
Finally, I was able to write the card on the eeePC with the original
Xandros system.
The symptoms are that you create/mount a file system and write data.
No errors are reported. But when reading back, some random sectors
of the card show bad data. I.e. the kernel may not boot because it
has a CRC error. But correct file size and date. Well, the MD5 sum
does not match any more.
fsck usually does not find these errors (because they rarely damages
the file system structures).
The only way to find out is running the badblocks tool.
If you get a static bad blocks pattern, your card is broken.
If you get a random bad blocks pattern, your reader is broken.
So it is *not* necessarily the card if you have problems on your Beagle.