Author Topic: Semaphore time out or Oddly behaving micro SD card  (Read 735 times)

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Offline G7PSK

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Semaphore time out or Oddly behaving micro SD card
« on: March 26, 2015, 08:41:16 pm »
Not sure under what category this should be if at all on this site, so its here as I do not understand whats going on which makes me a beginner.
I have just purchased an 64 GB micro sd card from Ebay for under £5. I thought that it could well be less than the claimed size and was interested to see but that is not the case. when I came to try and load large files onto it they failed to load and I got the message "semaphore failure" I tried the card in a USB adapter and the same files loaded without any trouble. Anyone have any ideas as to what is going on, I have tried the SD card on 2 computers with the same message coming up on the same files the card appears to function correctly in a camera as well as in the usb adapter  :-//
 

Offline marshallh

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Re: Semaphore time out or Oddly behaving micro SD card
« Reply #1 on: March 27, 2015, 07:03:50 am »
Throw the card in the trash, you can't trust it. It's probably a 1GB card with hacked CSD register to report a different size.

Some readers try to enumerate the card size by reading the last block. Obviously in this case this would be off in nowhere-land.
Semaphores are not explicitly used for card communications. Sounds like a higher level software stack is choking somewhere.

There are all manner of ways the card could fail in one reader but work in another.
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Offline G7PSK

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Re: Semaphore time out or Oddly behaving micro SD card
« Reply #2 on: March 27, 2015, 08:27:59 am »
I sent it back, but in a USB adapter I put several videos onto the card totalling nearly 8GB and it was not full but as an straight micro SD it would load or read the files.
 


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