Common Types of Memory Cards

PCMCIA (Personal Computer Memory Card International Association)
CompactFlash (CF), Secure Digital Card (SD card)
MiniSD Card
MicroSD
MultiMediaCard (MMC)
Sony Memory Sticks

Memory cards are quite sturdy and you can expect cards to be capable of working through more than one million data write/read/erase cycles. The card itself has its weakest point at its socket connectors, which are used when you remove and reinsert the memory card into a device. You can expect a memory card to be capable of withstanding around 10, 000 insertions. These numbers, of course, will differ slightly between manufacturers.

Like with any consumer electronic or device, proper care is required by the users to meet the lifespan of the device. You should avoid applying too much pressure on your memory cards, and never drop or bend the card either. When the correct memory card is being used in a device, it will fit into the slot only in one direction and it will easily slide and click into place. You should never have to apply any amount of pressure to make the card fit. Memory cards should also be kept away from electrostatic sources and should never be introduced to direct sunlight or extreme ranges of temperatures.

What is a 'smart card'?

A small electronic device about the size of a credit card that contains electronic memory, and possibly an embedded integrated circuit (IC). Smart cards containing an IC are sometimes called Integrated Circuit Cards (ICCs).

A smart card resembles a credit card in size and shape, but inside it is completely different. First of all, it has an inside -- a normal credit card is a simple piece of plastic. The inside of a smart card usually contains an embedded microprocessor. The microprocessor is under a gold contact pad on one side of the card. Think of the microprocessor as replacing the usual magnetic stripe on a credit card or debit card.

Smart cards are much more popular in Europe than in the United States. In Europe, the health insurance and banking industries use smart cards extensively. Every German citizen has a smart card for health insurance.

Magnetic stripe technology remains in wide use in the United States. However, the data on the stripe can easily be read, written, deleted or changed with off-the-shelf equipment. Therefore, the stripe is really not the best place to store sensitive information. To protect the consumer, businesses in the U.S. have invested in extensive online mainframe-based computer networks for verification and processing. In Europe, such an infrastructure did not develop -- instead, the card carries the intelligence.

The microprocessor on the smart card is there for security. The host computer and card reader actually " talk" to the microprocessor. The microprocessor enforces access to the data on the card. If the host computer read and wrote the smart card's random access memory (RAM), it would be no different than a diskette.

Smarts cards may have up to 8 kilobytes of RAM, 346 kilobytes of ROM, 256 kilobytes of programmable ROM, and a 16-bit microprocessor. The smart card uses a serial interface and receives its power from external sources like a card reader. The processor uses a limited instruction set for applications such as cryptography.

The most common smart card applications are:

· Credit cards

· Electronic cash

· Computer security systems

· Wireless communication

· Loyalty systems (like frequent flyer points)

· Banking

· Satellite TV

· Government identification

Smart cards can be used with a smart-card reader attachment to a personal computer to authenticate a user. Web browsers also can use smart card technology to supplement Secure Sockets Layer (SSL) for improved security of Internet transactions. Visa's Smart Card FAQ shows how online purchases work using a smart card and a PC equipped with a smart-card reader. Smart-card readers can also be found in mobile phones and vending machines.