How does moving the little switch on the side of an SD card write protect it when accessing it from a computer?
In: Technology
This was also done with floppy disks, music cassettes and VHS cassettes, and they made it work the same way on SD cards as they did on those older media: depending on the position of the switch, it either trips or doesn’t trip a little microswitch inside the card reader, telling the card reader whether it’s allowed to write to the card or not.
~~The tiny slide switch is connected to the tiny computer inside the SD card. If the switch is flipped, the controller disregards write commands coming from the host device.~~
The plastic bit depresses a small switch in the reader or not, depending on its position. Apparently it’s up to the reader/operating system to actually respect that request for read-only operation.
On SD cards it’s just a software thing. The card reader doesn’t have any mechanical ‘feeler’ or anything. Inside the card there’s some circuit thingy that gets switched and it’s super tiny and fragile which is why they break so easily.
Btw there are devices that refuse to work with a card on which write protection is enabled.
The little switch isn’t actually electronically controlled. Instead its read by the device that it’s inserted.
Latest Answers