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In Reply to: RE: Anyone had a MicroSD card they could not format?....... posted by Tony Lauck on July 25, 2014 at 13:30:43
Or do They suffer the same maladies as SD cards?Cut-Throat
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I don't use sd cards as drives in except in laptops because of quality issues and slow speed. An external hard drive is much better and faster.
No issues at all in cameras.
I suspect the cards work OK in cameras because the usage patterns, e.g. they don't write to the cards if the batteries are too low to complete the write and they don't shut off in the middle of a write.
I use these cards in a Raspberry Pi that is used to control some equipment. Most of the cards failed because of heavy write traffic, e.g. while doing an ArchLinux operating system update or by being powered down in the middle of a write. So far I haven't had any problems with a SanDisk Extreme SDHC UHS-1 card (8 GB) in my application but the Class 2 cards were junk.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
SD cards and thumb drives are not over provisioned like SSDs and do not implement rigorous wear leveling and do not directly support TRIM. It's quite conceivable that the same blocks are being written to excessively. Running fstrim occasionally might help.
The use cases for SD cards and thumb drives are quite different in cameras and other intended purposes. The read/write duty cycle of running a general purpose OS on an SD card would be relatively high compared to the duty cycle for it's intended use.
But regardless of media, everyone should maintain recent tested backups.
"But regardless of media, everyone should maintain recent tested backups."
Yes. Tested backups...
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Not sure there's any difference between a USB stick and an SD card. I have an adapter that takes an SD card on one end and plugs into a USB socket on the other. I use this to backup and restore SD cards that plug directly into a Raspberry Pi. The card that had Alzheimers showed the same symptoms used both ways.
I have heard that these cards have an embedded 8051 microprocessor that controls buffering, block erasing and remapping. If the data tables used by the firmware got confused in a crash situation this would explain various failure modes. While it might be possible to recover from some, doing so without any benefit of documentation would be extremely time wasting considering the low prices of these devices. I have come across web pages that describe how to hack the embedded microprocessors in SD cards. This might be amusing if you are into such things, but probably not an effective use of one's time if one has gotten beyond the curious teenager stage or is a professional spook.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Have you ever opened up a crashed 2.5" disk and torn it apart? I have. In the olden days disk platters were made of aluminum. Don't try bending a platter from a 2.5" disk drive. The platter is made of glass and will shatter into a zillion tiny shards. Ouch!
This might be of interest to you....
Just would not format my MicroSD card.
Cut-Throat
Not sure what to tell you. You might need to buy another card. Hope you didn't have anything too important on it.
Just didn't want to 'trash it' if there was an easy way to format it.
Cut-Throat
The software in my camera will reformat it's SD card.
My Tablet, about 5 different format programs and none of them could deal with this card.
Cut-Throat
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