A card connector which can interchangeably couple a holographic memory card or an electronic memory card to a card reader and/or writer which can then read and/or write to the coupled holographic memory card or electronic memory card. The card connector comprises: a memory card receiving section which can interchangeably receive the holographic memory card or the electronic memory card; and one or more card positioning members which cooperate with one or more card locating members on the coupled holographic memory card or the coupled electronic memory card to thereby repeatedly position the coupled holographic memory card or the coupled electronic memory card each time the holographic memory card or the electronic memory card is coupled to the card reader and/or writer, and is in a fully inserted card position, so that data can be read from and/or written to the coupled holographic memory card or the coupled electronic memory card.