NDIS might sound like another obscure acronym, but this project could open use of a host of wireless LAN cards to the Linux world: Only Atheros has openly embraced the open-source community by working with an intermediary who has developed Linux and FreeBSD drivers. The intermediary was necessary because Atheros (along with many other radio firms) uses software-defined radio (SDR), which if not properly secured would allow a programmer to use illegal frequencies. To avoid FCC trouble, Atheros worked with Sam Leffler, who privately developed a hardware abstraction layer that sits between the driver and the hardware. That code remains private.
Broadcom has been mocked and criticized repeatedly in open-source forums for not making a similar abstraction layer available so that Linux, FreeBSD, and other Unix-like platforms could use Broadcom's gear. (Older cards have had Linux and similar drivers written and companies released more information because the cards were hardwired to use just legal unlicensed frequencies in legal ways.)
The NDIS wrapper software emulates the abstraction layer in Windows that makes it easier for hardware vendors to write to a common specification instead of having to constantly develop custom drivers for each release of Windows. NDIS also lets software developers write to a standard abstraction instead of supporting each card and release.
By emulating NDIS, Linux users could simply write to the NDIS layer to build applications, which would include standard network interface clients. [via Slashdot]