I'm so sorry if this is a very naive-sounding question... but what do you mean by a mobile phone "writing"? How does the S3 or any mobile phone "write," and in what situations would we need them to "write"?
Additionally, why won't they write at class 10 speeds? Will they at class 6? I've got the S3 and I need to upgrade my sd card to a bigger one. However, I don't know what speed or GB to go with. Sorry for all these questions.
Oh, and do I need a card reader/WRITER to transfer my data from my old sd card to the new sd card? Or will a simple card reader (no writer) suffice? Thanks so much ahead of time!
"Writing" is just a simple way of saying "saving to the SD card. It is just like saving something on your computer. No special tools required. If you want me to give you the long drawn out explaination on how it happens I can, but lets just let it go at what I have said.
It is not so much that it will not write TO a class 10 card, it just may not be able to write at the maxium speed the card will allow.
Lokk at it this way, a Car can go 200 MPH, doesn't mean that it will.
In this day and age, I cannot see you even finding just a card reader, most of them do both right out of the box.
Transferring data is just this easy. Hook your phone (with your old card in it) up to your computer. When it shows up on the computer, move all the files from the card to a folder on your computer. Disconnect the phone, insert the new card, reconnect, move the files back.
Depending on how much data you have it shouldnt take more than 15 minutes or so.
PS there are no dumb or naive-sounding questions here on AC. We are here to help, do not hesitate to ask away.