AACRAID driver for FreeBSD and Mac OSX
This driver supports the following controllers:

• Dell PERC2/si
  
• PERC2/QC
  
• PERC3/si
  
• PERC3/di
  
• HP NetRAID 4M
  
• Adaptec 5400S
  
• Adaptec 2120S
  
• Adaptec 2200S
  
• Adaptec 2410SA
  

FreeBSD
The driver in FreeBSD is pretty much feature complete. All new features and bugfixes are submitted directly to the FreeBSD CVS tree, so please check there for the most recent driver. The RELENG_4 driver is a bit stale and I'm working to get it up to date. Please feel free to email me with any questions or bug reports.

Mac OSX
An experimental AACRAID driver for OSX is available here. It provides basic support for the cards mentioned above. Known issues:

• Booting from an array is not possible. Making this work is a significant task that involves writing a Forth driver for the card, along with extra magic in the driver to support the OS at bootstrap time.
  
• Energy Saving features of the OS are not supported. If the OS puts the system into low-power or sleep mode, it will quite likely confuse the card and create havok once I/O is resumed. I'm working on this.
• No management interface. There is no way to create or monitor arrays. You'll have to create the array using a PC and then transport the array over.
• Please remember that this driver barely qualifies as an 'Alpha' release right now. If it interests you, please send me an email. I will also be posting the source code to it soon.