Why do we format memory cards in cameras?

Just wondering why my instruction booklet for my camera is suggesting to format the memory card.

Why do we format memory cards in cameras?
"If you own camera memory cards that have been used in other digital cameras, the cards may not be properly formatted for use in your DC215 camera, or the data on the cards may have become corrupted. When these issues arise, your camera indicates that the camera memory card needs to be formatted.





When you format a camera memory card, all of the information on the card is erased. This includes any templates supplied on the card."





All cameras record and process data differently. Some create hidden files on the card that are necessary for unique operations (i.e. viewing the photos on the LCD screen, etc). Formating a card in the camera you want to use it in will help ensure the data doesn't become corrupt and your images will arrive on your computer intact. Kind of like making your own bed.





Most professionals will format their cards every time they put it back into the camera. Better safe!





Note that formatting will erase all photos on the card!
Reply:Because your camera will format the memory card in a format that it can read and write. If the card is unformated, there is no format or structure for the data to be written on. The format must be the same in order for your camera to read and write on.
Reply:the same reason we defragment a computer
Reply:A basic memory card is just a blank storage space. When you format it in the camera it allows the camera to insert its storage structure into the memory card in a way that is best read by the camera. If you look at the memory card in your computer, you will see that directories (folders) are created after formating. Once the card is formatted, it will prevent your card from being used inside a different camera.