user22900: I’m constructing an arduino based sytem that uses a SD card and I’m looking for a way to safely remove the card from the system during operation. One way would probably be to turn of the arduino before removal of the SD card, but that is not acceptable in this context.  
The library I’m using: 
https://www.arduino.cc/en/Reference/SD
Is it possible to safely remove the SD card during operation? If no, how can I minimize the risk of damage to the SD card while inserting and removing it? 

user368: The physical construction of the card and socket are designed such that power to the card is cycled properly when the card is inserted and removed. The only thing the firmware has to do is to stop writing to the card before it is removed.
Unexpected removal can cause a problem in "larger" systems (e.g. cellphones or PCs) because they may have structures open on the card that are not yet complete, but small embedded systems typically do not have the capability to do so and so once all writes are completed the card can be removed.
Detection of non-presence of a card is another issue though, and the firmware will have to be designed to not fail in such a situation.

user4909: In my early days of computing, the computer used to turn on a led when writing to cassette tape or floppy disk. If you wanted to remove the tape or disk, you had to wait for the led to turn off. 
I think that could be your easiest solution.

22900: <p>I’m constructing an arduino based sytem that uses a SD card and I’m looking for a way to safely remove the card from the system during operation. One way would probably be to turn of the arduino before removal of the SD card, but that is not acceptable in this context.  </p>

<p>The library I’m using: 
<a href="https://www.arduino.cc/en/Reference/SD" rel="nofollow">https://www.arduino.cc/en/Reference/SD</a></p>

<p>Is it possible to safely remove the SD card during operation? If no, how can I minimize the risk of damage to the SD card while inserting and removing it? </p>
 368: <p>The physical construction of the card and socket are designed such that power to the card is cycled properly when the card is inserted and removed. The only thing the firmware has to do is to stop writing to the card before it is removed.</p>

<p>Unexpected removal can cause a problem in "larger" systems (e.g. cellphones or PCs) because they may have structures open on the card that are not yet complete, but small embedded systems typically do not have the capability to do so and so once all writes are completed the card can be removed.</p>

<p>Detection of non-presence of a card is another issue though, and the firmware will have to be designed to not fail in such a situation.</p>
 4909: <p>In my early days of computing, the computer used to turn on a led when writing to cassette tape or floppy disk. If you wanted to remove the tape or disk, you had to wait for the led to turn off. 
I think that could be your easiest solution.</p>
