PCMCIA stands for Personal Computer Memory Card International Association. This industry association was founded in 1989 to develop a standard for credit card sized removable personal computer adapters known as PC Cards.
Most of the content on this page is based on the information found on http://www.pcmcia.org. Look there for more detailed descriptions.
The association has released the following PCMCIA specifications:
Release in 1990, the first PCMCIA specification established the basic PC Card standards, namely the 68-pin Interface Type I and Type II and the Card Information Structure (CIS) Metaformat. It supported memory cards only.
The 2.0 specification enhanced the memory card specifications and introduced support for I/O cards. It also added support for executing applications directly from the PC Card and defined card environmental requirements and standard test methods.
Version 2.01 focussed on mass storage and digital image support by intrucing the Type III form factor along with the PC Card ATA and other specifications. It also introduced the Card Services API.
PCMCIA 2.1 enhanced the Card and Socket Services specifications as well as the Card Information Structure.
Version 5.0, released in 1995, brought major enhancements to the PC Card definitions, most importantly in introduced the 32-bit CardBus Bus Mastering Interface, added support for Low Voltage-only Operation (3.3V), DMA, APM and multi-function cards.
PCMCIA 5.01 to PCMCIA 5.04
The most important improvements of the following minor releases were the introduced support for the Flash Translation Layer (FTL) as well as Custom Interfaces with the Zoomed Video (ZV Port) Custom Interface being the first one.
PCMCIA 6.0 to PCMCIA 7.2
Versions 6.0 to 7.2 of the specification added support for ISDN, Security and Instrumentation Cards as well as a couple of features and enhancements.
In April 2001 version 8.0 introduced the CardBay specification that combines the USB and IEEE 1394 standards into the PC Card format.
PC Card Types
The PCMCIA specifications define three physical sizes of PC Cards, known as Type I to III. Taken aside cards with extended form factors (used to enable devices that need to have parts outside the slot like wireless antennas, CD-ROM drives etc.) all three types measure the same width and length and they all use the same 68-pin connector. They only differ from each other in their thickness. Of course a thinner card can be used in a thicker slot, but not the other way around.
- 3.3mm thick
- typically used for memory devices such as RAM, Flash, OTP, and SRAM cards
- 5.0mm thick
- typically used for I/O devices such as data/fax modems, network cards, and mass storage devices
- 10.5mm thick
- typically used for thicker devices, such as rotating mass storage devices
Data Transfer Rates
The maximum throughput rates for PC Cards are as follows:
16-bit Memory Transfers
- Byte mode: 10 Mbytes/sec
- Word mode: 20 Mbytes/sec
16-bit I/O Transfers
- Byte mode: 3.92 Mbytes/sec
- Word mode: 7.84 Mbytes/sec
- Byte mode: 33 Mbytes/sec
- Word mode: 66 Mbytes/sec
- DWord mode: 132 Mbytes/sec
It you can boot from a PCMCIA drive depends on the BIOS implementation of the host system as well as the implementation of the drives controller, aka the PC Card. They both have to support it.