SCSI port level

Hi

If somebody has documentation for low-level (IO ports) programming for any simple SCSI controller, contact me please.
I need docs for _simple_ controller (without SCSI SCRIPTS or another complex technology) for virtual SCSI subsystem in our product (Parallels Workstation).
Thanks.

Regards,
Roman Filippov
Software engineer
Parallels Inc.
www.parallels.com