Atheros HAL

I came acroos to read this paper:
http://www.cse.iitk.ac.in/users/braman/students/2006/narasima.html

In this paper, the author implemented a 802.16-like MAC protocol on top of Atheros Madwifi driver. They were able to:

o Disable the backoff mechanism on Atheros card
o Partly disable virtual sense by increasing the CCA theshold
o Nullify DIFS, SIFS

These functions are not available in HAL. Thus we must set the hardware registers bypassing HAL. I also found the OpenHAL is actually inside the source of OpenBSD. I will look at the Open HAL code and continue to investigate how to achieve these goals.

FreeBSD architecture handbook

Useful for understanding the kernel internels of BSD.
http://www.freebsd.org/doc/en_US.ISO8859-1/books/arch-handbook/index.html