Bad Disk Fix - Page 1
Forum section: electronics / beginners

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: April 14, 2013, 05:47:49 pm
content: Hello i have a problem with my micro sd card high capacityits a 16GB kinston class 10 and when i plug it into my card reader (which hooks on to the motherboard via usb ( it is an internal connection to the motherboard pins and it says usb on the motherboard ) ) the green light which indicates that a card has been inserted wont light up also when i tried to open the SD with the Mini tool partition wizard home edition it said bad disk ..... i tried the chkdsk command and to directly open the chkdsk.exe from the system 32 but it did NOT fix the problem please help.

author: c4757p
author_rank: Super Contributor
timestamp: April 14, 2013, 05:57:02 pm
content: Well, either the card is bad or the reader is bad. Test the reader with a known good card, and if that's not it, your card is gone. You're not going to fix an SD card, it's literally just a flash chip.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: April 14, 2013, 06:00:29 pm
content: Thats the problem i got the same problem many times and i could be fixed with the chkdsk command the other times but now it just wont get fixed.Btw the reader is fine i tested it with other 2 cards the problem is the card but that happens to the card very often .....

author: c4757p
author_rank: Super Contributor
timestamp: April 14, 2013, 06:03:04 pm
content: If it's getting progressively worse, the flash memory is fried.

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: April 14, 2013, 06:10:16 pm
content: Nah it just gets bad only when i flash new roms to my mobile phone (xperia x8 ) ... and i copy files to it ... and now that i am thinking of it i think you are pretty right .... because it happens more often than it used to happen .... so i think ill search for a new sd ... thank you ... but generally is there a way to repair bad sectors on a disk or repair a bad sd ?

author: ChrisGreece52
author_rank: Frequent Contributor
timestamp: April 14, 2013, 06:11:54 pm
content: but what would you suggest ... kinston or sandisk and what class ??

author: JensAndree
author_rank: Contributor
timestamp: April 15, 2013, 08:15:36 am
content: Some readers will just not work with some mem-cards...I have three HP laptops of various age and only one of them will reliably write to my sdcards whilst running Windows. (with built-in reader)If I boot linux on them I can write to sdcard with dd on all of them. Perhaps the generic Windows drivers are crap or not tested enough, I don't know.For best reliability I use an external card-reader to access my sdcards and that never fails.I have also discovered that if I have read-errors on a sdcard (which raspi can do if very overclocked) I can always reformat the sdcard in my Xperia android phone!It skips the error checking and thus doesn't care that the card thinks it's broken and just happily (quick-)formats away.

author: orbiter
author_rank: Frequent Contributor
timestamp: April 15, 2013, 08:01:38 pm
content: Quote from: ChrisGreece52 on April 14, 2013, 06:10:16 pmOnly on a hard disk. An SD card is a different technology, as mentioned it uses flash memory and thus does not have sectors etc like a physical disk drive.Flash drives can only sustain a limited number of write and erase cycles before the drive will eventually start to fail. It sounds like your drivemaybe reaching this point.

author: JensAndree
author_rank: Contributor
timestamp: April 16, 2013, 09:08:28 am
content: Perhaps a bit OT...Many a year ago I worked with government-shady-security and CF cards were an issue.When writing a crypto filesystem I made some discoveries about flash memory I'd overlooked.Back then - and possibly still today? - a 128Mb CF card actually had appx 180Mb of storage but only 128Mb was useable.When "deleting" a file I noticed that the file actually never got deleted, only a byte was deleted so it looked like it as gone. (this is still the case with FAT and why you can undelete a file)When I tried to write code that actually deleted the file properly it started to write zeros on other addresses than the one my files used.CF cards had counters that tracked how many times segment was written and always shifted around the data in order to create an even usage.With this in mind one can "kill" a memorycard by fragmentation utilitiesBack to topic then. If I remember correctly all bytes that stopped working was marked "bad" and were replaced by the extra Mb data that was available in order to maintain 128Mb.If this is the case on modern sdcards I don't know but when my sdcards come up with errors I simply just reformat them with my phone (that ignores the errors) and then they are fully working again with the exact size as before.It was a very long time ago since I worn out a memory card due to writing too many times and I work in the phone industry with test automation amongst other things and I abuse memory cards daily without failures. Try to reformat it in a phone and see if it helps. If not, they cost nothing really and just replace it!