What is the difference between Secure Digital and Compact Flash memory cards for digital cameras?
SD vs. CF What’s the difference Secure Digital (SD) cards are quite a bit smaller and lighter than CF cards. They have a 9 pin interface rather than a 50 pin interface and this limits them to a 4-bit data transfer bus rather than the 16-bit data transfer bus of CF cards. In principle this makes their maximum possible transfer speed slower, but in practice there is little (if any) difference when used with current digital cameras. In the past SD cards were more expensive than CF cards and were not available in as high a capacity versions, but this is really no longer true. The very small size of SD cards means that they cannot accomodate microdrives. CF cards also have an onboard microcontroller for the memory which takes some load off the host, but this is currently more of theoretical interest than practical significance. The “Secure” in Secure Digital comes from the card’s origin which was concerned with digital rights managements schemes to prevent copying of music! SD cards contain
