www.pcmcia.org/faq.htm
Frequently Asked Questions About PC Card Technology 33 - What is the throughput of the PC Card interface? Try your card's manufacturer, or 49 Atek Electronics or 50 SupplyNet. What is the difference between Miniature Card, SmartMedia, Small PC Card, Multimedia Card and Compact Flash? PC Cards are credit card-size peripherals that add memory, mass storage, and I/O capabilities to computers in a rugged, compact form factor. PCMCIA (Personal Computer Memory Card International Association) is a non-profit trade association and standards body that promotes PC Card technology along with Miniature Card and SmartMedia cards by defining technical standards and educating the market. In the past, cards were known as "PCMCIA Cards", but the industry now refers to products based on the technology as "PC Cards," "PC Card Hosts" and "PC Card Software," and refers to the association as PCMCIA. The PC Card Standard provides physical specifications for three types of PC Cards, with additional provisions for extended cards. All three card types measure the same length and width and use the same 68-pin connector. Because they differ only in thickness, a thinner card can be used in a thicker slot, but a thicker card can not be used in a thinner slot. For the most part, release numbers are no longer used at the product level, as consumers were misinterpreting their importance when determining compatibility and interoperability. Card and Socket Services As the primary software specifications of PCMCIA, Card and Socket Services control the recognition and compatibility of PC Card devices. Socket Services is a BIOS-level software layer that isolates PC Card software from the system hardware and detects the insertion and removal of PC Cards. Card Services manages the automatic allocation of system resources such as memory and interrupts once Socket Services detects that a card has been inserted. Recent Improvements The rapid rate of adoption of PC Card slots over the last 4 years has driven a steady stream of card and host implementations. During that time, PC Cards containing new technologies were introduced, and significant new capabilities were added to the Standard. At the same time, considerable experience was gained by card, host and software vendors, and opportunities to improve compatibility were recognized. The February 1995 release of the PC Card Standard introduced more strict requirements for Card Information Structures, enabling easier identification of cards by host systems. The February 1995 release also saw the addition of the "Guidelines" document, a series of guidelines for developers of specific types of PC Cards. PCMCIA and the Plug and Play Association also co-sponsor "PlugFest" interoperability workshops, designed to bring together card, host and software developers to test their products together and resolve compatibility issues in a dynamic, open environment. Several books have been published in the last year that help developers to interpret the PC Card Standard. Enabled in the February 1995 release of the PC Card Standard, CardBus allows speeds of up to 133 Mbps at 33MHz. Zoomed Video is a connection between a PC Card and host system that allows the card to write video data directly to the VGA controller. The data is transferred with no buffering requirements because it is transferred over the ZV bus and not the system bus. The PC Card Standard is very flexible, allowing the integration of practically any peripheral device imaginable. The PC Card Resource Directory is a comprehensive catalog of PC Card products manufactured by members of PCMCIA. While it is not an exhaustive list, as listings must be submitted by the manufacturer, it is certainly an excellent place to start looking for a particular card. Another good way to start is by calling leading manufacturers of that kind of product in non-PC Card form factors. Many times, these are the first companies to develop PC Card versions of their products. In addition to the PC Card Standard, PCMCIA has available a number of books related to the design and development of PC Card products and software. The market for PC Cards is growing strong and expanding rapidly. In 1999, just three years from now, there will be more than 29 million platforms shipped with PC Card slots, representing 88% of all portable computing devices. Over 20 million cards will ship this year, and over 33 million cards will be shipped in 1997. With the continuing cooperation of the over 450 members of PCMCIA, PC Card technology is evolving as an industry-wide form factor, virtually assuring continued growth.
|