Technology Overview: The Promise of PCMCIA

Despite the rather staid title of Personal Computer Memory Card International Association, the PCMCIA (or PC Card) business has become one of the most dynamic aspects of the mobile computing industry.

Manufacturers continue to amaze everyone—including themselves—with the amount of features and circuitry that they can cram on the tiny credit-card sized boards.

However, in order for the market to graduate to the consumer mainstream—which includes using PC Cards with advanced consumer electronic devices in addition to computers—much has to be done in order for the devices to live up to their plug-and-play image.

The Genesis of PCMCIA

The PCMCIA was formed in 1989 to standardize the new generation of credit-card sized memory cards. However, people soon began to realize that they could pack a lot more into this tiny form factor and, before long, pressure was building to add a new format for I/O functions such as modems and LAN adapters.

PCMCIA Chronology

• 1985 – Japanese Electronic Industry Development Association (JEIDA) defines 68-pin card.
• 1989 – PCMCIA founded.
• 1990 – Release 1.0 for memory cards introduced.
• 1991 – PCMCIA and JEIDA agree to cooperate, PCMCIA 2.0 and JEIDA 4.1 jointly accepted.
• 1991 Release 2.0 introduced including support for modems, LAN adapters, and others.
• 1992 – Support added for rotating mass storage.
• 1992 – Socket and Card Services 2.0 introduced.

Type I, II, and III

One of the defining elements of the PCMCIA Specification relates to the physical sizes of the cards. Currently, three sizes are defined and are known as Type I, Type II, and Type III. Each size contains the same number of pins (68) along its edge connector, however differ in the thickness.

Type I, Type II, and Type III cards measure 3.3, 5.0, and 10.5 mm respectively. Type I has historically been used for memory cards, including SRAM, Flash memory, EEPROM, and One Time Programmable (OTP). Type II cards often make use of the extra space to add features related to I/O such as fax and data modems, local area network adapters, and wireless communication adapters.

Type III cards, at double the thickness of Type II cards, were designed to support the new class of small, 1.8-inch rotating magnetic media. However, they can clearly be used for any application that requires additional space to enclose extra components.

A New Type IV?

While the PCMCIA considered the addition of a Type IV card measuring 13 mm, this was ultimately rejected since it was felt that the current sizes provide adequate flexibility.

This, however, has not stopped manufacturers such as Toshiba and IBM from going ahead and building devices conforming to this “unofficial” Type IV standard. In the short term, this is likely to be the source of some confusion.

The Promise

For PCMCIA devices to offer maximum benefit, the following three features must be well implemented:

• Device independence
• Seamless installation
• Hot swapping

Ideally, most cards should work on every platform, regardless whether the device is a Newton, a ThinkPad, or a digital cellular phone. At one level, this requires a strict implementation of the PCMCIA 2.0 Specification, including adherence to the functions provided by the Card and Socket Services (see next page).

Installation and configuration of the card should also be made as transparent as possible. Many of the devices incorporating PCMCIA slots are increasingly being targeted at the high-end consumer electronics market. Constantly reminded of the flashing “12:00” on VCRs, manufacturers must make these devices as simple as the phone or television.

The importance of this cannot be overstated. Bill Atkinson, co-founder of General Magic recently commented on what the flashing “12:00” is saying to people: “Stupid, stupid, stupid.” He’s absolutely right.

Finally, these devices must support hot swapping, enabling cards to be replaced without rebooting or powering down. This is another ease-of-use issue that cannot be overlooked.

Before we can realize PCMCIA’s vast potential, manufacturers need to start devoting as much attention to hardware interface design as software developers did to user interfaces in the past decade.