Memory And Connectivity With PCMCIA And PC Cards, Continued
It is important to consider the bandwidth of such devices, i.e. the path inside the notebook.
|16-bit I/O Transfer||16-bit DMA Transfer||Cardbus (32 bit burst mode)|
|Byte mode||3.92 Mbytes||10 Mbytes/sec||33 Mbytes/sec|
|Word mode||7.84 Mbytes||20 Mbytes/sec||66 Mbytes/sec|
|Dword mode||132 Mbytes/sec|
The performance increase with the Cardbus 32bit marked the giant step from the old ISA world to the new PCI world. A modem card might not benefit from the 32bit access, but a 100Mb network card does.
Together with the 32bit transfer, the PC Card specification added the ZV (Zoomed Video) Port. The ZV Port is a point-to-point unidirectional video path from a PC Card to a graphics chip plus an audio chip.
With such a ZV Port PC Card you can add a camera or MPEG2-decoding (DVD-decoder cards) to your Notebook.
Recently Intel pushed forward with two new Standards for Mobile Computing, which are 'MiniPCI' for internal PCI cards and 'MDC' (Mobile Audio/Modem Daughter Card). PCI slots are too big for a notebook, but there is a need for optional features like Ethernet LAN, token ring LAN or other upgrades like e.g. Bluetooth. A MiniPCI card provides the flexibility needed to react to the market for such features. Usually, a built-in notebook modem is a proprietary design for a specific notebook model. With all the certification needed to support a modem around the world, it is a nightmare to use that certified design for one notebook modem model only. In this case the MiniPCI and MDC standards help at lot.