osol-discuss - Why are so many adapter card drivers closed source?

I was shocked to find that the drivers for all sorts of storage and
network adapters (including for pretty standard stuff like the Adaptec
Ultra320 SCSI cards and Broadcom wired network cards) that have been
supported by open drivers in Linux and *BSD since more or less the
beginning of time ;)
Were these developed under some kind of a NDA or are they simply not
being released in the hope that the community will someday port over
the *BSD drivers?
Mike

On 04/22/10 04:25 AM, Michael Kerpan wrote:
I don't know about the ones you mention, but a number of drivers are
supplied by the silicon vendor. Vendor's own drivers often take
advantage of features of their silicon that they don't want to make
public. I have worked on drivers that were written under paranoid NDAs
for that reason.
Sure you can write an open driver based on published interfaces, but
they won't perform as well (nVidia being a prime example).
The OpenSolaris license is less restrictive than the GPL, so it's easier
to bundle closed drivers in a distribution.