The current success of the memory cards had its origins already in the mid-80s of the past century. They were the size of credit cards, and the lack of standardization meant that every manufacturer created its own proprietary standard. The then existing memory technologies permitted only limited memory capacities, at very high costs. For example, a 512 Kbyte SAM card was priced at about DM 1,000.- back in 1990. These Memory Cards were exclusively used by the industry. Only the invention and development of the FLASH memory technology by TOSHIBA created the basis for the implementation of cost-effective Memory Cards with high memory capacities, which could also be overwritten by the user as often as desired and did not require power for data retention. In addition, an increasing number of developments created a real need for this kind of storage medium. Since then, FLASH memory cards have been increasingly popular in consumer applications. It can justly be said that memory cards are one of the most important storage medium of today and tomorrow. The main applications are: • Digital cameras • Photohandys • MP 3 players • Palmtops • Multi-functional mobile phones • Dictating machines • and many more ... There are a multitude of memory card standards – We present to you the currently existing systems: (the order in no way represents a judgement)

The ATA FLASH memory card (ATA = AT Bus Attachment) was first developed for industrial use because of the extreme compatibility problems among the FLASH variants of the linear PC Cards (after all, every new memory chip required new programming algorithms, and special FLASH file systems were required.< BR >
For the first time, a controller was integrated on a memory card to handle the entire memory management. Since the size of this card is based on the PC Card standard, it is too large for most consumer applications and is therefore hardly used in such products any more today.

A reduced-volume variant of the ATA Flash Card is the CompactFlash Card. Featuring the same electrical design, it is barely half the original size and uses only a 50-pin connector (36.4 mm x 42.8 mm x 3.3 mm). Full compatibility with the familiar PC Card slot can be achieved by means of a simple adapter. Each card contains one or more memory chips and the associated drive logic. Due to the large number of memory chips, this technology enables higher memory capacities than other systems (e.g. SSFDC, MMC, SD or Memory Stick). Memory capacities up to several Gbytes are currently available. This memory card type is currently the leading design worldwide. As with the ATA Flash Card, the CF Card is available in different heights. A distinction is made between Type I (3.3 mm thick) and Type II (5.0 mm thick). Type I cards can always be used in a Type II card slot (but not vice versa). It has even been achieved to build a mechanical harddisk into a CF Type II housing (IBM Microdrive).

This cost-effective memory card has a very simple design, containing only the memory element itself (without any drive/controller circuitry). A simple plastic substrate carries 1 (or 2) Standard NAND FLASH memory chip(s), which is (are) directly bonded to the back side of the contact surface. Remarkable in the mid-90s were the very small dimensions of the card of only 37.0 x 45.0 x 0.76 mm, which resulted in the wide-spread use of the SmartMedia Card in the consumer area, e.g. in DSC, MP3 players, dictating machines and so on. Initially, the card also existed as a 5-volt variant (with a beveled upper left corner). Today, only the 3 (or 3.3)-volt variant is used. These cards are available with memory capacities of 8, 16, 32, 64 and 128 Mbytes. Meanwhile, the advanced state of standardization has eliminated the initial compatibility problems that occurred when new cards with higher capacities became available.

As the trend to reduce the volume in a wide variety of consumer applications continues, so does the demand for even smaller memory cards. This resulted in the MultiMedia Card that features minimum dimensions of 32 x 24 x 1.4 mm. The card contains a controller that handles the entire data transfer and also the memory management. The card has 7 pins. Major initial uses of the MMC were mobile phones and MP3 players. Because of the copyright protection issue that is particularly apparent in MP3 players, the MMC was used as a basis to develop a new memory card, which has a copy protection feature to prevent unlawful, uncontrolled copying and offers higher memory capacities due to its thicker design. The SD Card is generally considered a very promising technology. Capacities up to 512 Mbytes are currently available. Due to the high compatibility between them (the SD Card has 2 additional pins and is 2.1 mm thick), both types are interchangeable in many applications. Volume-reduced miniature variants for both card types have been announced or have already been introduced.

In parallel with the development of the MMC and SD Card, design efforts pursuing the same objective resulted in the implementation of the Memory Stick from SONY. Today, it is mostly used in the company’s products and has quickly gained a sizable market share on this basis. However, it should be noted that there are number of different variants. In addition to the standard variant (only available up to 128 Mbytes), there is the Memory Stick Duo (a reduced-volume variant) for corresponding applications. Both types are also available as Magic Gate – similar to the SD Card, this is designed to prevent the unauthorized copying of copyright-protected content. The Memory Stick PRO was developed for applications that require higher memory capacities and/or faster data transfers (e.g. video recording) – however, it should be noted that this product is not compatible with many older applications. Another product is the Memory Stick Select, which uses a mechanical switch to override the existing upper limit of 128 Mbytes for the memory capacity.

The xD-Picture Card is the latest memory card type. Technically, it is closely related to the SmartMedia Card (only FLASH chip on memory card/no controller).

However, the xD-Picture Card is considerably smaller and thus conforms to the trend of miniaturization of applications (20.0 x 25.0 x 1.7 mm).

It is mostly used by the two camera manufacturers Fuji and Olympus, where it replaces the SmartMedia Card.

Generally, it can be stated that no specific memory card type has an absolutely dominating position today.
In the future, too, different card types are expected to coexist in the market, although with varying market shares.
However, the days of the SmartMedia Card should be numbered: The successful classic will have to give way to the fast rate of technological progress.
This progress will also ensure that new types of memory card will be developed in the future and become available to consumers.

For data exchange with the PC, readers/writers (also called photo readers) are available with one or more slot(s) for the various memory cards, and adapters for the most common interfaces.