PCMCIA
The PCMCIA is the Personal Computer Memory Card International Association, an industry trade association that creates standards for notebook computer peripheral devices.
The best known such devices are known as PC Cards (formerly PCMCIA cards). A later revision of the PC Card is known as CardBus. The PCMCIA is also developing a new notebook peripheral specification called Newcard or ExpressCard.
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2 CardBus 3 Newcard/ExpressCard 4 External links 5 See also |
PC Card
A PC Card is about the size of a credit card. There are three different sizes, varying in thickness: Type I is 3.3mm thick, Type II is 5.0mm thick and Type III is 10.5mm thick. All are 85.6mm long and 54.0mm wide. Most notebooks take two Type II cards or one Type III.
As per the original name, the first PC Cards were for memory expansion. However, the existence of a usable general standard for notebook peripherals led to all manner of devices being made available in this form. Typical devices include network cards, modems and hard disks.
The electrical specification for the PC Card is also used for CompactFlash, so a PC Card CompactFlash adapter need only be a socket adapter.
CardBus
The original PCMCIA bus is 16-bit. CardBus is a 32-bit version, which runs at 33MHz, of the same standard physical sizes. CardBus also includes bus mastering, which allows a controller on the bus to talk to other devices on the bus without going through the CPU. This allows for faster transfer rates.
Since CardBus is 32-bit and supports bus mastering, this makes it sufficiently similar to PCI that many chip sets can be adapted to both PCI and CardBus cards, such as those that support Wi-Fi.
Newcard/ExpressCard
The PCMCIA is working on a replacement for the present card, to be called Newcard or ExpressCard. It uses PCI-Express and is physically smaller. Dell Computer will be shipping machines using Newcard in the second half of 2004. [1]